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1 Vacuum Dehydrator:The Complete Guide for Beginners and Professionals

Vacuum Dehydrator:The Complete Guide for Beginners and Professionals

Are you struggling to remove water in lubricating, hydraulic, gear or compressor oils?

If yes, then you’re definitely in the right place.

Today, I want to show you how to remove 90-95% of all dissolved water and 100% of emulsified or free water in hydraulic systems. You’re going to learn everything about an important accessory that removes all contaminants in hydraulic systems – Vacuum dehydrator.

By the end of this guide, you’ll be able to maintain high fluid cleanliness standards, increase lifespan of components and minimize possible downtime.

Now, let’s dive right in:

Vacuum Dehydrator
Chapter 1:

What is a Vacuum Dehydrator?

What is a Vacuum Dehydrator?

A vacuum dehydration oil purification system is an electromechanical machine that depends on various heating principles and vacuuming technologies to remove gaseous substances, particulate and water from oil.

Since vacuum dehydrator was developed decades ago, it is one of the most efficient and reliable way to remove contaminants from hydraulic oil.

In fact, you cannot compare it to other filtration systems such as centrifuging and coalescing.

Obviously, depending on your hydraulic system, you may deal with water that exists in different forms.

I’ll explain that shortly.

Also, depending on the amount of water in oil, it may result in both chemical and physical changes in oil. This may adversely affect is performance and reliability of hydraulic systems.

Remember, water is one of the most “stubborn” contaminants in hydraulic systems. A reason why a vacuum dehydration oil purification system is a must have accessory.

With this accessory, you can achieve a cleanliness level below 10 to 20ppm.

I know you’re beginning to wonder how this is possible…don’t worry you will know more about the working principle of vacuum dehydrator in chapter 3.

For, now, let me take you through various forms in which water exists on hydraulic systems.

1.1. Phases of Water in Hydraulic Systems or Oil

Generally, water as a contaminant exists in three phases in hydraulic systems. Failure to remove water in any of these states can be catastrophic to the entire system.

And, at any given point, it is important to choose a machine that can remove water in all the three phases.

That’s why I recommend a vacuum dehydration oil purification system.

Now, let’s see the phases in which water exists in hydraulic oil systems:

Dissolved Water

This is the amount of water that has been dissolved in oil. Basically, you cannot see it and in many instances, you may confuse it with oil.

It is the same scenario as dissolving salt in water. Once it dissolves, it forms a solution, whose concentration can only be determined by conducting some tests.

That is the same scenario here.

In most cases, as the temperature increases, oil tends to dissolve more water. However, there is always a limit to this – a point where oil is saturated and can take no more water.

Free Water

This is a “visible” form in which water may exist in hydraulic systems. This is what I am talking about:

Water Free oil

Photo credits: Terry n Williams

As you can see from the image above, there are a few things that are clear:

  • You can easily separate the two by decanting
  • In most cases, water tends to form the bottom layer. This because the specific gravity of most hydraulic oils is less than 1.00.

Apart from this, water may also exist in hydraulic oil as:

Emulsified Water

So, what’s the difference here?

This is water that has blended with hydraulic oil. Unlike the free oil, here, you cannot remove water by decanting.

Emulsified water

Emulsified water

Mostly, it will remain blended with oil such that it neither falls out, nor settles at the bottom.

The bottom line:

Water exists in 3 phases in oil and you must adopt a technology that can remove this contaminant.

With that in mind, let’s see under what circumstances you should choose an oil dehydration system.

Chapter 2:

When to Choose a Vacuum Dehydrator for Your System

When to Choose a Vacuum Dehydrator for Your System

I know you’re a beginning to wonder when you should go specifically for oil vacuum system.

Here we are:

In this section, I am going to focus on major instances where only a vacuum dehydrator can be your only option. These include:

When you need Less than 10 to 20 ppm of Water in Hydraulic System

When it comes to cleanliness of oil in hydraulic systems, you can’t take any chances. This is because the kind of damage contaminants can cause in your hydraulic system will be catastrophic.

Why do I say so?

In a research that was conducted by Ez Kopecký on Water in Hydraulic Oil, he goes ahead to list the following as some of the most devastating effects of water:

Effects of Water in Hydraulic SystemEffects of Water on Hydraulic Oil
  • Corroding surfaces of hydraulic systems
  • Reduces the lifespan of filters
  • Causes valves lock, especially in an event of an ice crystal
  • Increases hydraulic system parts wear
  • Rapid silting of orifices and valves
  • Deteriorates oil additives such as anti-wear additives in oil
  • It reduces viscosity of oil
  • Accelerates oil oxidation

Furthermore, the research goes ahead to illustrate how moisture affects machine’s lifespan. You can see this in the graph below:

Moisture Content of Oil (PPM)

Now, with all these, it is quite clear that you should keep your hydraulic oil free from water or moisture.

The only equipment that can attain a cleanliness level of 10 to 20 ppm is a vacuum dehydrator.

For example, FilSon Filter vacuum dehydrator can remove 100% of free and emulsified water. Besides, it removes 90 to 95% of dissolved water.

Frankly, this is a high level of water removal efficiency that you can only achieve by adopting vacuum dehydrator oil purification system.

Removing all the 3 Phases in Which Water Exists

Let’s face the reality:

In most cases, people claim that water and oil are immiscible.

From chapter 1, I was quite clear that water can exist in oil as dissolved, emulsified or free solution. So, the reality is that at any given point, you will be dealing with 3 different contaminants.

Also, I can assure you that there is virtually no equipment that can remove all the three phases of water.

I know this can be a surprise to many but, here is the truth of the matter:

Method of Separating Water from Hydraulic OilPhases of Water it Removes from Oil
GravityRemoves free water, partially removes emulsified water and does not remove dissolved water
Centrifuge unitsCannot fully break emulsified water. It removes only free water
Desiccant unitsLimited water removal capability and only efficient in removing ingressed particles and air
CoalescerDoes not work well with viscous oils. It removes free water only.
Absorbing elementsRemoves only free and emulsified water from oil
Vacuum dehydrationRemoves free, emulsified and dissolved water

Now, what can you conclude from here?

It is quite clear that vacuum oil purifier is the only accessory you can count on when it comes to removing water in different phases.

As you will see later in chapters 3 and 5, a vacuum dehydrator oil purification system is single machine that removes all the 3 phases of water. So, you don’t have to go through numerous and expensive processes or removing this contaminant.

But that alone is not enough.

Vacuum Dehydrator Removes Gases in Hydraulic Oil

Entrained air and gases can adversely affect the normal operations of hydraulic systems. In fact, in some situations, it will obviously lead to system failure.

Even when it comes to this, vacuum dehydrator is the only accessory that can remove 100% of free gases and nearly 90% of dissolved gases. This is critical in some applications such as those of transformer and lube oil.

Vacuum Dehydrator Removes Gases in Hydraulic Oil

Photo Credits: Machinery and Lubrication

Remember, some of the devastating effects of air in hydraulic systems include:

  • Spongy control; the system will be less stiff and softer
  • Loss of horsepower
  • Loss of system fluid
  • Erosion and cavitation

Of course, these are not the only effects of air in the hydraulic system. The effects of air will depend on the location and type of hydraulic systems.

In short, to ensure efficiency and reliability of hydraulic systems, you must remove the air. This is where a vacuum dehydrator system plays a fundamental role.

Removes Particulate from Oil

Whenever we refer to contaminants in oil systems, you will not only deal with water and air, but also certain particles too.

Again here, even though you can remove these particles using other filtration system, a vacuum dehydrator still offers a perfect solution. That is, an all-in-one solution – removing air, particles and all phases of water.

A transformer oil filtration system

A transformer oil filtration system – Photo Credits: Study Electrical

Isn’t this what you‘re looking for?

Well, keep reading to learn more:

A vacuum oil filter machine features highly efficient filter systems that eliminate all particulate matters as per ISO 16889.

Basically, with these systems, you can achieve extremely low particulate counts that meet the ISO cleanliness standards.

Still, your choices are not limited to only these 4.

Remove Varnish from Hydraulic Oil System

This is a critical aspect when you’re dealing with turbine oils.

In most cases, the vacuum dehydrator may feature a granular adsorbent.  With this, it can remove all types of soluble varnish in hydraulic oil, ensuring there are virtually no contaminants.

A section of vacuum dehydrator

A section of vacuum dehydrator

From my experience, it is important that you adopt an effective filtration mechanism that can prevent any possible contaminations. This can be particles, varnish, air or water.

Once you remove all these contaminants, your hydraulic system will obviously guarantee high efficiency and performance.

The bottom line:

It is only a vacuum dehydrator oil purification system that can remove air, varnish, particulate and all phases of water from oil.

Thus, it guarantees efficiency and reduces possible downtimes – more of these benefits are in chapter 8.

For now, I want to take a step further and explain how an oil dehydration system works.

Chapter 3:

Vacuum Dehydrator Working Principle: How does a Vacuum Dehydration Oil Purification System Works

Vacuum Dehydrator Working Principle

In this chapter, I am going to show you how an oil dehydration system works. As I had mentioned earlier, this is an effective way of removing water, gases and particulate from oil.

By the end of the process, you should have clean oil that will not affect the normal operation of the machine.

As you will see in the vacuum dehydrator working principle, this machine removes all phases of water (free, emulsified and dissolved water), gaseous and particulate matter from the oil.

The vacuum oil purifies achieves this degree of cleanliness in different stages. I am going to explain all those here.

Let’s dive right in:

Step 1: Heating Oil to a Suitable Temperature

Once you connect the oil dehydration system, oil will flow into the system. Of course, this is the contaminated oil you’d wish to purify.

The first step is to heat the contaminated oil to a suitable temperature.

This is a critical stage since it should ensure that the heat does not interfere with the basic oil constituents.

Normally, this is a critical step, on how a vacuum dehydrator works. This is because it is virtually impossible to remove contaminants in either highly viscous or cold oil without heating.

Heating element for oil dehydration system

Heating element for oil dehydration system

Now, depending on the oil or vacuum dehydrator, you can heat the oil to a temperature of 55 to 65°C.


It is critical to limit the temperature within this range to prevent possible thermal breakdown of the hydraulic oil.  Besides, it is still economical to maintain the temperature within this range.

The truth is:

At this stage, it is important to avoid any instances of permanent deterioration of oil such as a permanent change in oil viscosity.

oil viscosity

Photo Credits: UTEXAS

Remember, as you increase the temperature of oil, its viscosity tends to decrease. This is because temperature makes oil molecules to become hyperactive.

In addition to this, there are certain additives that will deteriorate at extremely high temperatures.

Step 2: Distillation Column of the Hydraulic Dehydrator

This is a critical stage in the working principle of the vacuum dehydrator oil purification system. It is at this stage that this vacuum oil purifier removes water in the oil.

At times, you can also refer to this column as a vacuum chamber.

So, what exactly takes place here?

The vacuum dehydration system has a vacuum pump. It is this vacuum pump that creates vacuum in this column.

In most instances, it draws the vacuum at about 18 to 27” Hg.

As you draw this vacuum, it is important to remember that, very high vacuum will lead to slower water removal.

This leaves you with only one option:

You need to have a proper balance between vacuum and temperature to effectively remove water and gases from the oil.

Position of the vacuum chamber of hydraulic dehydrator

Position of the vacuum chamber of hydraulic dehydrator

Now, as oil flows through the dispersion medium in the vacuum chamber, both the dissolved gases and water present in oil are “boiled off”. This effectively dehydrates the oil.

Remember, the essence of passing heated oil in a vacuum chamber is to ensure the oil is dehydrated at a relatively low temperature. With this, there is no possibility of thermal breakdown of oil.

Within this column, the vacuum oil purifier dehydrates and degasses oil without changing or altering any of its properties. That is, it removes all phases of water and gases.

I hope you remember the three phases of water that I discussed earlier.

Also, it is worth noting that the choice of these parameters will depend on the type of oil you intend to purify. For instance, synthetic oil requires higher temperatures than standard mineral oil.

Still, the oil purification process does not end here.

Step 3: Removing Particle in Hydrated and Degassed Oil

Now that the oil is free from both gases and water, it is now time to remove all particles.

At this point, the oil discharge pump will remove dehydrated water from the vacuum chamber and pump it to a particulate removal filter.

Location of the filter system

Location of the filter system

At this point, the filter system will remove all particulate matter in oil. Of course, this should conform to the ISO 16889 (βc>1000).

From here, you will have clean oil that is free from:

  • All phases of water
  • Gases
  • Particles

You can now cycle the oil back into the hydraulic system or pump to the reservoir.

As you can see, this is an automatic process that does not require your intervention at any point. Once you key in appropriate parameters, the system will purify oil and recirculate it back to the system.

In addition to these, some hydraulic dehydrators are designed such that, oil will recirculate within the system until it is fully dehydrated.

For a fact, the efficiency of these systems depends on the design and configuration of various parts and components. I will take you through that in chapter 6 of this guide.

Also, depending on the design of the machine, all water that it removes via a vacuum pump can either be:

  • Released to the environment
  • Condensed in the reservoir tank

In a nutshell:

A vacuum dehydrator oil purification system heats oil and introduces vacuum thereby removing all water and grease. Then, it uses filter systems to remove possible particles in oil.

It is a straightforward, simple and efficient process.

With that in mind, let me take you a step further and discuss the functions of vacuum dehydrator.

Chapter 4:

Vacuum Dehydrator Functions

Vacuum Dehydrator Functions

You could be asking yourself this question:

What are the main functions of a vacuum dehydrator oil purification system?

I will explain all that here:

i. Remove Free, Emulsified & Dissolved Water from Oil

This is the primary function of vacuum dehydrator and purification system. Remember, water is one of the most “stubborn” contaminants in oil more so, where it exists in a dissolved state.

The design of these filters is such that:

  • Most machines use a fin tube heater to heat oil to a suitable temperature. A process that is precisely monitored and controlled for efficiency.
  • Large surface area in the vacuum chamber exposing the oil to vacuum

With these, a vacuum dehydrator can remove 90 to 95% of dissolved water with 100% of free and emulsified water. Therefore, with an oil vacuum system, you can maintain water level below 10 to 20 ppm.

Of course, this is possible with proper choice of an efficient vacuum dehydrator oil purification system.

The best part:

This is an automatic process which you can control and monitor via a PLC system. As a result, accuracy and efficiency are high.

PLC control panel for vacuum dehydrator

PLC control panel for vacuum dehydrator

As you will see later in this guide, there are essential design parameters and features that guarantee this efficiency. For instance, there are numerous valves and gauges for flow controls, with sensors that measure other parameters.

In short, whenever you want to dehydrate oil, it is important to consider:

  • Flow rate; this depends on your hydraulic system
  • Vacuum flow rate
  • Size on inlet and outlet connections
  • Heating efficiency and temperature

Of course, these are alongside other factors such as dimensions and weight of the oil dehydration system.

The truth is:

A vacuum dehydrator system will remove all water in any type of oil irrespective of the viscosity. Whether you are dealing with gear, brake or transformer oils, a vacuum dehydrator offers a perfect oil purification solution.

ii. Removing Gases from Oil

Very small amount of free or entrapped air can be a disaster to any hydraulic system. In fact, it can cause total failure of the system.

Well, with a vacuum dehydrator, you don’t have to worry about dissolved gases in oil anymore.

The design of these systems is that they help remove 100% of free gases and 90% of dissolved gases in hydraulic oils.

Dissolved gases in transformer from an online monitor

Dissolved gases in transformer from an online monitor – Photo Credits: Research Gate

So, how does a vacuum filter machine achieve this?

Well, by supplying a suitable amount of heat and vacuum, the vacuum dehydration oil purification system effectively removes gases from oil.

iii. Removing Particle from Oil

With the help of various filter systems, a vacuum dehydrator oil purification system removes all particles in the hydraulic systems.

In fact, with special types of filters, this vacuum oil purifier can remove varnish and acid, alongside other contaminants.

Remember, at times these particles can be too small to an extent that you cannot see them. However, with an appropriate filtration system, your hydraulic oil will definitely remain free from particulate matter.

To achieve this, you must choose an appropriate filter that will not allow any particles to pass through.

This filter does not remove 100% of particles from the hydraulic oil

This filter does not remove 100% of particles from the hydraulic oil – Photo Credits: Machinery and Lubrication

By the time oil leaves the vacuum dehydrator oil purification system, it should be free from gases, water (all phases) and particulate matter.

There is a reason why I decided to focus on these three main functions of vacuum dehydrator.

When you achieve all these, other functions or machine performance will be automatic.

The truth is:

The next functions of vacuum dehydrator systems I am going to discuss depend on these three.

Let’s dive right in:

iv. Extends Component and Bearing Life

Do you remember my discussions in chapters 1 and 2 of this guide?


In lubrication oils, water can lead to the loss of hydrodynamic oil film. As a result, this can lead to excessive wear in various components and bearing life.

According to Machinery Lubrications, about 1% of water in hydraulic oil can reduce the service life span by nearly 90%. You can see this is quite devastating.

Furthermore, emulsified and free water in oil can be catastrophic in the loading section in bearings. They do cause high erosive wear.

Water in hydraulic oil may also cause bearing to become brittle and weak, thus, can easily crack. I know you’re wondering how this can be possible.

Let me explain:

At high pressures, especially in load zone of bearing, water may break down to its individual atoms – hydrogen and oxygen atoms. The bearing can then absorb hydrogen resulting in hydrogen embrittlement.

It is this hydrogen embrittlement that causes bearing or metal components to become brittle and eventually fracture. You can learn more about it in the video below:

With a vacuum dehydrator oil purification system, this will be a thing of the past – there will be virtually no water in oil.

A similar research was also conducted by Richard E. Cantley in an experiment: The Effects of Water in Lubricating Oil on Bearing Fatigue.

Again, it is evident that water increases bearing fatigue life.

You can see this in the graph below on the effects of water in oil on bearing life:

Wind Power Engineering

Photo Credits: Wind Power Engineering

v. Extending Fluid Use Life

Here’s the reality:

Water ingression is one of the most destructive contaminant thus you need to remove it as soon as possible.

And, as I had stated earlier in this section, the main function of vacuum dehydrator oil purification system is to remove all phases of water.

Frankly, water causes oil degradation, poor lubrication and contributes to the drastic change in corrosive wear.

For example, water changes the viscosity of oil – it may thicken or make it thin depending on the type of oil. Once it alters the viscosity of oil, you have no choice but to change the oil (it has basically reduced the service lifespan on fluid).

Viscosity refers to the hydraulic fluid resistance to shear or tensile stress that may cause gradual deformation

Viscosity refers to the hydraulic fluid resistance to shear or tensile stress that may cause gradual deformation

In addition to this, water causes oxidation in lubricating oils. Obviously, this will result in premature aging of oil.

Again, some oil additives are readily hydrolyzed and may produce acids that eventually cause corrosive effects.  These oil additives may include anti-wear (AW) or extreme pressure (EP).

Still, the effects do not stop there:

Even the demulsifying agents, rust inhibitors and dispersants in oil can easily be washed away by excess moisture.

Clearly, when you use a vacuum dehydrator to remove oil, you’ll basically extend fluid life.

So, what do all these guarantee?

vi. An Increase in Productivity and Low Operation Costs

From my discussion in the above 4 points, I guess this is quite straight forward.

That is, when your hydraulic fluid works optimally, with virtually no premature wear, you will:

  • Increase productivity since machine will operate optimally with no common downtimes
  • Lower costs of operations due to minimal breakdowns and repairs

Of course, as I had mentioned, you can achieve this by adopting vacuum dehydrator oil purification system that removes all phases of water, gases and particulate matter.

Now that you know the various functions of vacuum dehydrator, let more a step-further and analyze how this equipment looks like.

That takes us to another critical subject in this guide: vacuum dehydrator design and drawing.

Chapter 5:

Vacuum Dehydrator Design and Drawing

Vacuum Dehydrator Design and Drawing

May be, you have been wondering how a vacuum dehydrator looks like. That is exactly what you’re going to learn here.

The truth is:

Different vacuum dehydrator manufacturers strive to design unique and efficient systems that can remove water, gases or particulate.

Please note that, this is an introductory chapter to what you are about to learn in the chapters:

  • 6 which focuses on main parts of a vacuum dehydrator
  • 7 which explores the main features of vacuum dehydrator

For now, let’s focus on the vacuum dehydrator design and drawing.

In any engineering field or even before the actual manufacturing process begins, there must be technical drawing. This is basically a representation of the actual equipment you intend to fabricate.

Let’s have a look at this:

FilSon Filters Vacuum Dehydrator

FilSon Filters Vacuum Dehydrator

In this vacuum dehydrator design and drawing, you can see three different sides. It basically shows critical components of this vacuum dehydration unit.

The two images at the top are side views of the vacuum dehydrator i.e. from different sides. On the other hand, the bottom image shows how a vacuum dehydrator looks like when you view it from the top.

Now, it is from these drawings that a vacuum dehydrator manufacturer will fabricate the final product such as this:

Side view of FilSon Filters Vacuum Dehydrator

Side view of FilSon Filters Vacuum Dehydrator

Side view of FilSon Filters Vacuum Dehydrator

Side view of FilSon Filters Vacuum Dehydrator

In short, this is how a vacuum dehydrator design and drawing looks like. As mentioned earlier, all manufacturers are at liberty to have unique designs of an oil vacuum system.

It will all depend on what they give high priority as far as efficiency, reliability and ease of installation.

However, this is not all when it comes to vacuum dehydrator design and drawing. You should consider this too:

5.1. Vacuum Dehydrator Process Flow Diagram

Can you remember how a vacuum dehydrator works?

I did discuss that in chapter 2 – you may go over it quickly in case you’ve forgotten.

Anyway, let’s get back to what you need to learn here:

A process flow diagram is a representation of how a vacuum dehydration oil purification system will perform certain functions. It is basically how vacuum dehydrator works.

It shows:

  • How contaminated oil gets into the vacuum oil purifier
  • Process of heating oil and subjecting it to vacuum; this removes gases and water
  • How the machine directs water vapour to a condensation tank or releases it into the environment
  • Process of removing particles that may be present in oil from the vacuum chamber

In short, the vacuum dehydrator design and drawing, aims to implement this process flow.

Here is an example of process flow diagram for a vacuum dehydrator:

Vacuum dehydrator process flow diagram

Vacuum dehydrator process flow diagram – Photo Credits: Parker

As you can see, from the above process flow diagram, it is easier to know how a vacuum dehydrator works.

The bottom line:

Before you buy any vacuum dehydrator oil purification system, you must evaluate:

  • Technical drawing and designs
  • Process flow drawing and design
  • 3D representation of the machine (pictorial representation)

With all these, you will know exactly what you expect from an oil dehydration system. So, it is critical for both vacuum dehydrator manufacturers and buyers.

However, the discussion on vacuum dehydrator drawing and design doesn’t here.

In this chapter, you’ve seen drawings, some of which you may not know what they are.

For that reason, I want to take you to yet another important aspect of this guide – main parts and components of vacuum dehydrator.

Chapter 6:

Main Vacuum Dehydrator Parts List

Main Vacuum Dehydrator Parts List

From the definition of a vacuum dehydrator – this is an electromechanical machine with many parts assembled together.

Even the vacuum dehydrator drawing in chapter 5, is basically a representation of many parts assembled together.

Having said that, why don’t we explore and learn what these parts are and their respective functions.

And here we go:

1. PLC System

The modern vacuum dehydration oil purification system features a fully automatic control system. It not only guarantees accuracy, but ensures consistency in the entire oil purification process.

Furthermore, these systems feature different sensors (as you’ll see later in this section) to monitor various process. You have to integrate all these using a reliable and robust control system.

It is for this reason that most vacuum dehydrator manufacturers use a programmable logic controller (PLC). This way, they can monitor and control all process in vacuum oil filter machine.

See the control panel of the vacuum dehydrator

See the control panel of the vacuum dehydrator

Basically, they have a fully automatic system that allows for precise control of all processes without any possibility of guess work. In fact, this vacuum dehydration unit cannot start when it is not configured properly.

Furthermore, with the help of a microprocessor, the system ensures safe oil purification. Remember, the PLC system will automatically shut down the entire machine in case the operating conditions go beyond the set limits.

In some machines, the PLC system features a touchscreen HMI. It allows users to configure and monitor vacuum dehydration process of oil.

2. Pumps

To remove water, gases and particles, oil must flow through various systems in the vacuum oil filter machine. So, to ensure there is consistent flow, the vacuum dehydrator must have an appropriate pump.

The number of pumps in a vacuum oil purifier will depend on the design and configuration of the machine. Remember, it is the pump that determines the flow rates in the vacuum oil filter machine.

Vacuum pump

Vacuum pump – Photo Credits: BEST VALUE VACS

In the standard vacuum dehydration system, you may have the following main pumps.

  • Inlet pumps; it should be a special type of pumps that is not affected by any of the contaminants you want to remove. The inlet pump directs contaminated oil into the vacuum dehydration unit for purification.
  • Vacuum pump; remember to remove water and gases at relatively low temperature, you need a vacuum system. This is why you need a vacuum pump that can evacuate gasses and moisture from the vacuum chamber.
  • Outlet pump; it pumps the dehydrated and degassed oil from the vacuum chamber to the filter.

In short, for oil to flow from one point to another the machine must have an appropriate pump.

3. Strainer & Filters

Removing water and dissolved gases is never enough. Remember, the hydraulic fluid or oil may have other contaminants.

It is for this reason that vacuum oil filter machine must have strainer or filter systems.  These filters may include:

  • Inlet strainer

As the inlet pump directs oil or hydraulic fluid into the vacuum dehydrator system, this filter will remove particles present.

Of course from here, it will go to the heating and later vacuuming system.

However, this process may also not guarantee “zero” particles in the final product. Thus, you need to integrate the second filter.

  • Strainer

This strainer is located just after the vacuum system. It is made of a micro glass filter element that guarantees cleanliness that conforms to ISO 16889.

Filter element

Filter element

That is, the degassed and dehydrated oil passes through a ßx [c] ≥1000 filter system. Their design should guarantee quiet filtration process and long service lifespan.

Other filters within a vacuum dehydrator oil purification system can also include:

  • Dual stage filters to remove any possible particle contamination. You can also have this either as an inlet or outlet filter.
  • Suction filter; it removes any particles that may reduce the lifespan of the pump. As a result, it enhances the lifespan on the pump.

As a rule of thumb, you must know the rating, capacity and type of pump.

4. Heating System

As I had mentioned earlier, heating is an important procedure in an oil dehydration system. This is the reason why you need to be cautious when it comes to choosing the heating system.

It should be a heater that delivers just the right amount of heat – neither too low nor high. This is to ensure that it does not interfere with the purification system or oil additives.

What am I talking about here?

I’d recommend a vacuum dehydrator oil purification system with a low watt density heater. Such heaters lower the cost of oil purification.

This is because it:

  • Heats oil faster
  • Easy to control to prevent any possibility of overheating
  • Guarantees uniform heating of oil
Heater element

Heater element

Alternatively, some vacuum dehydrator heater manufacturers may opt for segmented heating systems. Such heaters guarantee better dewatering without any possibility of oil deterioration.

5. Vacuum Chamber

A vacuum chamber is the nerve centre of vacuum oil filter machine. This is where all the critical processes take place.

It is in the vacuum chamber that this unit removes gases and water from oil. Remember, the two are some of the most “stubborn” contaminants in the oil.

In most cases, a vacuum chamber is made of stainless steel, with a vacuum pump.

Although the design of this chamber varies with the design of the vacuum dehydration unit, it should have a large surface area.

It should be such that it creates a thin film of oil. This way, a large surface area of oil will be exposed to the vacuum.

By exposing the heated oil to the vacuum, the system flushes out both gases and moisture from the oil. This leaves behind degassed and dehydrated oil.

Position of the vacuum chamber in hydraulic systems

Position of the vacuum chamber in hydraulic systems

Furthermore, there are machines that may feature permanent dispersion media. This also provides a larger surface area for maximum water extraction.

Therefore, the amount of water and gases a vacuum dehydration system can remove will depend on the design of the vacuum chamber.

Also, another factor that plays an integral role here is the position of the vacuum chamber.

In most vacuum dehydrator designs, the vacuum tower is elevated to ensure gravity flow. Besides, it is a better option when purifying high viscous oils.

6. Condenser

Condensers come in different configurations depending on the unique design of the machine.

In most cases, a number of vacuum oil filter machines have air cooled condensers.

Process flow diagram

Process flow diagram – Photo Credits: HY-PRO

It is these condensers that changes vapour into water. This water then flows to the condenser tank or may drain from the system.

Of course, this will still depend on the design of the vacuum dehydrator machine.

7. Pressure Switch

These are valves that control the flow of oil, after and before the filtration process. Again, the number of valves in a vacuum dehydration oil purification system will also depend on the design of the unit.

For instance, a standard vacuum dehydrator may have a valve to protect the low watt density heater. Alternatively, another one shuts down the condensate tank system.

I hope you can remember the exact location of these components from the vacuum dehydrator process flow diagram.

Section of a pressure switch

Section of a pressure switch

You should note that the inlet and outlet level switches regulate outlet of the pumps. This helps to maintain a suitable level in the vacuum.

8. Warning Indicators

Warning indicators are in the form of LED lights or alarm. At any given instance, whenever there is any fault in the system or inappropriate configuration, the warning indicators will relay the same.

Warning indicators

Warning indicators

Again here, the system automatically detects and diagnoses faults, thanks to the robust PLC systems of the vacuum dehydrator systems.

9. Wheels

Not all vacuum oil filter machines have wheels. However, these wheels are common in portable vacuum dehydrator machines where they allow for easy maneuverability.



10. Drip Tray

The drip tray is in the bottom section of the vacuum oil purifier. It prevents oil from spilling on the floor, thus helping to keep the working area clean.

Section of the drip tray

Section of the drip tray

11. Frame

Every part of vacuum oil filter machine is hosted within a structure – a vacuum dehydrator frame. It may take any shape, however they are made from strong material such as steel.

Frame of a vacuum dehydrator system

Frame of a vacuum dehydrator system

Besides, they have a heavy duty base that can support the weight of the vacuum dehydrator and oil during filtration. Furthermore, the design of the base should be such that it is easier to lift with a forklift.

12. Sensors

You cannot talk of a fully automatic system without mentioning sensors. It is these sensors that detect the actual system parameters such as pressure difference, rate of flow, temperature, humidity, etc.

They then relay this signal to the PLC for interpretation.

Temperature sensor

Temperature sensor

Some of the main sensors:

  • Pressure gauge; detects system pressure to ensure it does not exceed the normal operating conditions.
  • Temperature sensor; this may include a thermostat or thermocouple, which protect the system from overheating. They may be integrated with digital temperature controller.
  • Moisture sensor; it shows water content in % saturation. This ensures better water removal.

13. Varnish Removal

Special designs of vacuum oil filter machines may have absorbent media. It removes varnish, especially in transformer and turbine lube oil.

14. Electric Motor

It converts electrical energy to mechanical energy (a rotary motion). As a result, it helps rotate the pump impellers to pump fluid to and from the vacuum oil purifier machine.

Parts of an electric motor

Parts of an electric motor

As you can see, a vacuum oil purifier machine has many parts and components. Remember, these are just the main parts.

So, before you purchase any of these machines, it is important that you know every part and component. You will get this information from the technical manual.

With that, let’s move further to explore another essential aspect of vacuum dehydrator – unique features of vacuum oil purifier.

Chapter 7:

Features of Vacuum Dehydrator

Features of Vacuum Dehydrator

To remove particles, dissolved gases and water (in all the three phases), you must buy a vacuum dehydrator with the right features.

Again, from chapter 4, it is evident that vacuum oil purifiers come in a range of shapes and designs.

Therefore, this section will focus on the main features of vacuum dehydrators that are common in most designs. These features include:

Vacuum System

This section plays an integral in a vacuum dehydration oil purification system. It is at this point that the system removes all water and gases in oil.

Therefore, any design feature must aim to improve efficiency and reliability.

For instance, a standard vacuum system may include the following:

Vacuum Pump

To create a vacuum in the oil dehydration system, you need a vacuum pump. Its efficiency will determine how well the machine removes both gases and water.

Vacuum pump

Vacuum pump

Among the key features you must consider in a vacuum pump are:

  • Rotary vane which is always in CFM
  • Size
  • Type of material
  • Performance characteristics


Remember, a vacuum oil purifier dehydrates oil by evaporating water. Thus, this water turns into steam, which the machine must condense.

A condenser system may have:

  • Condensate holding tank
  • Air or water cooled system
Condenser system

Condenser system

Remember, even the fluid must return to the system or reservoir tank at a stable temperature. That is the initial temperature before heating and vacuum in the vacuum dehydrator system.

Filtration System

Particulate matter is also part of contaminants a vacuum oil purifier should remove in the oil. Therefore, a vacuum dehydration unit must have an effective filtration system.

Different types of filter systems

Different types of filter systems

When it comes to the filtration system, you should consider the following key features:

  • Filter Element ßx(c) ≥ 1000; therefore, you need to consider the micron of the filter element
  • Filter housing; this is the section that hosts the filter element

In most cases, a vacuum oil purifier system may have both an inlet and outlet filter.

Heating System

Do you remember the discussion in chapter 3 – the vacuum dehydrator working principle?

Even before the oil goes into the vacuum chamber, you need to increase its temperature.

You must be cautious here not to overheat oil. This is because high temperature may degrade various additives in the oil.

Besides, an appropriate choice of heating system may increase the cost of operation.

Depending on the capacity of the vacuum dehydration oil purification system, it may come with many of heat capacities. This may range from 12, 16 to over 128 KW.

Circuit diagram showing various features of vacuum dehydrator

Circuit diagram showing various features of vacuum dehydrator – Photo Credits: ENERVAC CORPORATION

In the recent past, quite a number of machines feature a low watt density heater. It is efficient, reliable and lowers the operation costs of a vacuum dehydration unit.

Automatic Control System

Vacuum dehydration unit features a fully automated control system for efficient and reliable filtration.

Basically, this implies that the machine should have various sensors and automation software. Mostly, quite a number of oil vacuum systems feature a PLC.

With PLC systems, a vacuum oil purifier can remove all contaminants without human intervention.  This allows for accuracy and consistency in removing, gases, water and particles in oil.

PLC system, gauge and indicators

PLC system, gauge and indicators

A vacuum oil purifier control system may include numerous sensors to measure different process parameters. These may include:

  • Inline Moisture Indicator and Particle Monitor

Remember, the main aim of installing a vacuum oil purifier is to remove all forms of contaminants in the oil.

Therefore, during the process, you should be able to monitor and control the process. This is why moisture sensors and particle monitor play a key role here.

  • Digital and Automatic Temperature Controller

Here, we have sensors that are also integrated with the PLC control system. The aim here is to ensure stable and consistent heating.

Therefore, you don’t have to adjust the temperature – the machine will automatically do it for you.

  • Pressure Sensors

It is important to maintain the vacuum dehydration system at a specific working pressure. This way, it will remove all water, gases and particles without altering various properties of oil.

Warning Indicators

These are the indicators you will see in situations where the vacuum dehydrator oil purification system is not working properly.

Depending on the design of the PLC control system, you will see the warning indicators in the case of any of the following:

  • Dirty filter
  • Low or high oil levels
  • High temperature
  • Certain components are not working properly

With the help of warning indicators, you can easily monitor and troubleshoot vacuum dehydrator easily.

In case of a problem, the alarm should alert you to take appropriate measure. Of course, the alarm system is also configured in the PLC system.

From the HMI control panel, you can monitor and control various operations of the oil dehydration system.

The point is:

The vacuum dehydrator PLC system will start, stop and monitor various operations of during oil purification system. It controls, pumps, gauges, flow switch, level switch, etc.

Structure of a Vacuum Dehydrator System

What material is the vacuum dehydrator made of?

This is a fundamental question that you need to ask yourself all the time.

Normally, the choice of material will depend on the type of fluid you want to purify. As a rule of thumb, the hydraulic fluid must not react with the materials.

That is, whether it has been heated and subjected to vacuum, or before; with this, you will avoid unnecessary contaminations that can also be catastrophic.

Internal components of vacuum dehydrator

Internal components of vacuum dehydrator

The bottom line:

You must evaluate very component – from heating, vacuuming, filtration, etc. to ensure they meet high quality standards.

In most cases, vacuum oil purifier is made from stainless steel. However, the base is made of carbon steel.

Here’s the point:

By evaluating and choosing a vacuum oil purifier with appropriate features, you will easily remove water, gases and particles from the oil. Of course, this is for your own good and that of the hydraulic system.

Remember, the number of features will depend on the unique design of the machine. That is, vacuum dehydrators in more complex hydraulic systems tend to have a robust control system.

It may include programming of the PLC, number of sensors or overall design of the system.

With all these in mind, let’s have a quick overview of the benefits of vacuum dehydrator.

Chapter 8:

Five Top Benefits of Using Vacuum Dehydrator

Five Top Benefits of Using Vacuum Dehydrator

You could be asking yourself this question:

What are the main benefits of the vacuum dehydration system?

I will not lie to you:

Vacuum dehydration units are common in modern hydraulic circuits due to the numerous benefits which the machine guarantees.

I hope you can remember the discussions in chapter 2 and 4 – they laid a foundation for what I am about to discuss here.

Below are the top 5 benefits of using a vacuum dehydrator system:

1. Highly Efficient in Removing Contaminants

I had mentioned this earlier:

Oil or hydraulic fluid may have water, gases, particles, acid or varnish as the main contaminants.

As you may have noticed in various discussions in this guide, vacuum dehydration unit removes all these contaminants. It does so in a single process that is continuous and fast.

Oil before and after filtration

Oil before and after filtration – Photo Credits: HYDRAULICS & PNEUMATICS

For instance, you should expect the following degrees of cleanliness when you adopt a vacuum dehydration process. It removes:

  • 100% free and emulsified water alongside free gases
  • 90 to 95% of dissolved water
  • 90% of dissolved gases
  • All particulate

Clearly, adopting a vacuum dehydration oil purification system guarantees a high degree of cleanliness in hydraulic systems. It is basically efficient when it comes to removing any form of contaminants in hydraulic fluid.

2. No Costly Maintenance of Filter Systems and Machines

Once you maintain a high level of cleanliness, you don’t have to worry about replacing machine parts and components more frequently. It will increase the service lifespan of components.

Now, back to the filters:

Vacuum dehydration is not like coalescing systems where you have to replace filter elements frequently. Even with frequent replacement of coalescing elements, it cannot remove dissolved gases and water.

Maintaining noisy hydraulic lifters

Maintaining noisy hydraulic lifters – Photo Credits: HOT ROD NETWORK

Once you opt for an oil vacuum system, there will be no need to worry about costly replacement of coalescing elements.

3. Vacuum Dehydrator is designed for Continuous Operation

From the working principle of vacuum dehydrator in chapter 3, you can see that it purifies oil in a continuous process.

It begins from heating, vacuuming, dehydration, degassing to removing particles. Therefore, oil that will be leaving the system will be clean and free from any contaminant.

This makes it a perfect choice for both continuous and unattended operations. Thanks to the automated system, which allows the machine to monitor and control all critical parameters of the machine.

4. Safe and Easy to Operate PLC System

By turning the machine into automatic mode, you will eliminate human intervention that is prone to errors. Of course, this reduces the cost of manpower.

With the PLC system, it is easier to operate and use a vacuum dehydration system. By pressing appropriate knobs the systems will:

  • Run and stop automatically
  • Remove all possible contaminants
  • Display process parameters
  • Detect faults and stop the equipment automatically to ensure safety.

As you can see, this is quite convenient and reliable, besides the fact that it does all these processes in a continuous process.

Basically, you don’t have to worry about costly downtimes that may affect productivity.

5. Eliminates Varnish, Colour and Acid

Whenever you’re dealing with transformer, turbine or gear oils, there could be possibilities of other contaminants. These may include varnish, colour or acid alongside water, gases, particles, etc.

Clean engine oil

Clean engine oil – Photo Credits: ABOUT MACHINERY PARTS

The good news is:

Once you have an appropriate vacuum dehydration system, you don’t have to worry about varnish, colour or acid in the oil.

In parallel with regeneration unit that increases the dielectric strength, a vacuum oil filter machine eliminates colour and acid.  Besides, it also removes all varnish.

Clearly, once you invest in a suitable vacuum dehydrator oil purification system, there will be no need to worry about any contaminant in the hydraulic fluid.

The bottom line:

A vacuum dehydration system is an accessory you can count on when it comes to maintaining high degree of cleanliness in hydraulic fluids or oils.

This implies that you can use a vacuum dehydrator unit in numerous applications as you will see shortly.

Chapter 9:

Vacuum Dehydrator Applications

Vacuum Dehydrator Applications

In this chapter, I want to take you through 11 different practical applications of vacuum dehydrator units.

As you have seen in the previous chapters, this machine offers an ultimate filtration of hydraulic fluid or oil. It doesn’t matter whether your system has water, gases, particulate matter or varnish.

A vacuum dehydration unit will ensure that only clean oil or hydraulic fluid circulates in your system.

Anyway, let’s have a quick review of the various vacuum dehydrator applications:

1. Filtering Hydraulic Systems

This is one of the main applications of the vacuum dehydration unit. In filtering hydraulic system, the main aim is to remove all possible contaminants that can compromise performance.

In hydraulic systems, depending on its unique application, you may encounter many contaminants such as varnish, water, gases, etc.

Therefore, as a general rule, it is important to adopt an accessory that will guarantee the efficiency of filtering hydraulic systems.

Illustration of hydraulic filtration system

Illustration of hydraulic filtration system – Photo Credits: GLOBAL SPEC

Remember, filtering hydraulic systems refers to an assembly of different components whose aim is to eliminate possible contaminants.

Depending on your unique applications, you’ll get one that meets your specific filtration requirements.

2. Filtering Steam Turbine Lube Systems

In steam turbine lube systems there is a high chance of contaminants infiltrating the oil system. Besides, there is a tendency of vented oil mist emissions more so in the reservoirs, which can also contaminate the oil.

Circuit diagram of lubrication system

Circuit diagram of lubrication system – Image source: TURBOMACHINERY

Remember, a steam turbine lube plays an integral role in machines that generate power to the plants.  Furthermore, it can contain the very large amounts of oil – over 30,000 litres.

You can image how catastrophic this could be to have that volume of oil contaminated.

To ensure the oil remains dry and clean at all time, you must install a vacuum dehydration unit. This will save you from expensive repairs and downtime that may cost your plant.

3. Industrial Equipment Containing Oil

Let’s face it:

Most industries and machineries depend on oil to perform various tasks. This could be for lubrication, carrying or lifting heavy loads like in the case of cranes.

Others include excavators, hydraulic brakes, power steering, etc.

To ensure efficiency and optimal performance of these machines, you need clean oil which is free from any form of contaminants.

Gear oil must remain clean at all times

Gear oil must remain clean at all times

This leaves you with no option but to go for a vacuum dehydration unit. It will continuously remove all contaminants.

4. Purifying Hydraulic Oil

You need to keep hydraulic oil clean all the time for an optimal performance of the systems. This is critical in situations when you have to reuse oil back into the system.

For a fact, hydraulic oil gets contaminated when in use thus the need to use a vacuum dehydrator to remove contaminants.

Hydraulic oil

Hydraulic oil

The good thing about the vacuum dehydration unit is that it can purify hydraulic oils of different viscosities. Whether it has gases, water, particles or varnish, it will ensure the oil remains safe for use.

Also, the process of purifying oil is precisely controlled to avoid any instances of degrading hydraulic oil.

5. Cleaning Turbine Oil

After some time, turbine oil will get contaminated with moisture, varnish or air. Therefore, you need to clean it to prevent instances of the oil damaging the turbine components.

Section of turbine

Section of turbine

Whether you have a gas or steam turbine, it is important to ensure the oil remains free from any form of contamination.

Remember, this will also affect the time frame which turbine oil will remain effective. You should note that contaminants such as water are just but a few aspects that reduce the service lifespan of turbine oil.

Other aspects may include heat, operation hours and various maintenance procedures.

6. Maintain Cleanliness of Lubrication Oil

Your bearing and other parts will wear out faster when you use contaminated lubricating oil. It is for this reason that you must maintain the cleanliness at all times.

Besides, in gears and moving parts, you cannot afford to stop the machine to lubricate it. It should be a continuous process.

Thus, a vacuum dehydrator becomes a perfect choice for this task. Once you set it to automatic mode, it will purify lubrication oil continuously.

Lubrication oil

Lubrication oil

With a suitable vacuum dehydration unit, you don’t have to worry about any possible bearing or component failures.

7. Cleaning Gear Oil

Like the lubricating and hydraulic oil, you need a machine that can clean gear oil without changing any of its properties. This leaves you with no option but to choose a vacuum dehydration unit.

Through the action of temperature, vacuum and various filter elements, a vacuum dehydrator will remove water, gases and any other contaminants.

By ensuring gear oil is clean all the time, you will increase their lifespan and this will save you from unnecessary maintenance costs.

Gear oil

Gear oil

Furthermore, once you switch it to automatic mode, the vacuum dehydrator for gear oil will continuously keep the oil clean.

8. Purifying Transformer Oil

The situation is not different when it comes to purifying transformer oil.  Normally, transformer oil may have a range of contaminants such as:

  • Colloidal particles
  • Paint, adhesive or polymer particles
  • Acidity
  • Moisture


This may result in elevated power factors and at times, the transformer may fail completely.

As you can see, the transformer oil may have many contaminants. Therefore, you need equipment that will remove all these contaminants all at once.

With this, a vacuum dehydration unit will be the only solution.

9. Diesel Fuel

A clean diesel fuel will guarantee efficiency in the overall performance of the machine. As you know, diesel fuel may have gases, water, particulate or other contaminants.

All these will undermine performance and reliability of the machine that depend on diesel fuel. In fact, these contaminants may lead to incomplete combustion hence, excess pollution.

Pouring engine online

Pouring engine online

Adopting a vacuum dehydrator oil purification system will guarantee consistent and continuous flow of diesel fuel to the system.

It’s this simple:

Avoid costly maintenance and inefficiency by adopting a vacuum dehydrator.

10. Phosphate Ester

Phosphate esters are popular fire resistant basestock in many applications such as in compressors, hydraulic and turbines.

Although they play an integral role in ensuring performance and reliability of hydraulic oil, they can also cause contamination. It is for this reason that you need to adopt a reliable and trusted oil purification procedure.

With an oil vacuum system, you can remove excess of these compounds without affecting the general performance of oil.



Remember, high polar base oils with phosphate ester tend to be more hygroscopic and may hold more water. This makes the oil purification system even more challenging.

Therefore, you need a vacuum dehydration unit that can remove water in all the three phases.

11. PAO Fluid

PAO fluids are common in most conditioning units. In fact, they have replaced the silicate ester in a number of military electronics.

The POA is common in many hydraulic fluids, lubricants, greases, etc. They are some of the most popular synthetic oils in the market.

Even though they play an integral role here, it is important to monitor and regulate contamination that could be due to the PAO fluids. Under such circumstances, you need a vacuum dehydration unit.

So, what’s the bottom line?

As long as you’re using hydraulic fluid, oil or lubricants, you need a way to maintain the fluid cleanliness. You need a machine that will remove all possible contaminants – be it water, gases, varnish or particles.

Basically, you need a vacuum dehydrator. More importantly, you must buy this accessory from a reputable vacuum dehydrator manufacturer.

Let me take you through some of the main vacuum dehydration unit manufacturers in the global market.

Chapter 10:

Top 8 Vacuum Dehydrator Manufacturers

Top 8 Vacuum Dehydrator Manufacturers

In this section, I am going to take you through top 8 vacuum dehydrator manufacturers in the global market.

With this information, I am sure you can easily choose suitable oil vacuum systems depending on your unique designs and specifications.

Below are the main vacuum dehydrator manufacturers you can consider when it comes to this:

1. Parker

With fortunes in over 250 countries, Parker Hannifin has become a world leader in vacuum dehydrator manufacturing. Since its inception, the company has invested in a range of oil purification systems which include:

  • Catridge oil filters
  • Marine filter assemblies
  • Vacuum dehydrators
  • Hydraulic fluid purification systems, etc.

Parker offers low to high pressure filter systems that meet high cleanliness standards.



Parker vacuum hydraulic units come in many shapes and designs. These include the Parker PVS and Sentinel series.

They all feature compact design and robust structures besides being portable, allowing for more flexibility in oil purification process.

To learn more about Parker vacuum dehydrators and other hydraulic filtration systems, you can follow this link: Parker Hydraulic Filter Division.

2. Pall

Pall Corporation is one of the leading high-tech filtration companies. It has optimized its filtration systems for many industries such as aerospace, petroleum, food processing, aerospace vehicles, etc.

Pall Corporation

Pall Corporation

Like Parker, Pall has also invested in various oil purification systems, aiming to extend machine and fluid life.

According to the information on Pall, their vacuum dehydration unit removes 100% of free water and gases. At the same time, the vacuum dehydrator systems remove 80% of dissolved water and gases.

Furthermore, the Pall vacuum hydrator system features a Beta rated (ßX(c)>1000) filtration element. You can follow this link for more information on the Pall vacuum dehydrator system.

3. Schroeder

Schroeder is yet another reputable vacuum dehydration oil purification systems manufacturer. Of course, this is alongside other filtration systems that Schroeder designs and sells to the global market.



The Schroeder Vacuum Dehydrator (SVD) comes in many shapes and designs for hydraulic and lubricating systems.  Like other manufacturers, the Schroeder Vacuum Dehydrator (SVD) comes in different capacities to meet the dynamic needs in the hydraulic system industries.

Depending on the model of the vacuum dehydrator oil purification system, they can remove 0.75gph to 2.00gph of free water.

For more information on these products, follow this link: Schroeder Vacuum Dehydrator (SVD).

4. FilSon Filters

If you’re looking for quality and cost competitive hydraulic filter system, then FilSon Filters is a Chinese manufacturer you can count on. From its duplex filters, simplex filters, filter carts to filter housing, they are all made from high quality material and standard to international standards.

Notably, FilSon Filters vacuum dehydrators are designed to remove 90 to 90% of dissolved water and 100% of free and emulsified water. This guarantees better filtration than even the Pall vacuum dehydration units.

Besides, they remove 100% of free gases and 90% of dissolved gases. Also, it has a Beta rated (ßX(c)>1000) filtration element that removes particles per the ISO cleanliness standards.

FilSon Filters

FilSon Filters

With an easy to control PLC system and high efficiency (as lows as 10 – 20 ppm of water), FilSon Filter vacuum dehydrators are systems you can count on.

For more information, follow this link: FilSon Filters Vacuum Dehydrator.


HY-PRO Filtration is a global leader in designing and manufacturing a series of hydraulic filter system. Their main products include duplex filter assemblies and vacuum dehydrators.

Of course, they are designed for many filtration solutions – from low to high pressure filtration.

HY-PRO Filtration

HY-PRO Filtration

HY-PRO Filtration is popular for its VUD series of vacuum dehydrator systems. Their unique design aims to balance between heating and vacuuming process, thereby removing water and dissolved gases.

These VUD series of vacuum dehydrators include Vac-U-Dry systems, equipped with filter element alongside the gases and water removal system.

The good thing about HY-PRO Filtration vacuum dehydrators is that you can equip them with other technologies such as turbine oil varnish and ester acid removal.

For more information about their products, follow this link: HY-PRO Vacuum Dehydrators.

6. Donaldson Filtration Solutions

With decades of innovation in the filtration industry, Donaldson Filtration Solution is one of the leading vacuum dehydrator manufacturers in the global market.

Apart from vacuum dehydrators, it offers a range of oil, fluid and fuel filtration systems such as coalescers, LTC transformer filtration, bearing lubrication and high flow filter skids, amongst others.

Donaldson Filtration Solutions

Donaldson Filtration Solutions

The Donaldson vacuum dehydrators feature a unique design, with the ability to remove particulate, dissolved gases and water from fluids. They can remove 100% of free and emulsified water and about 90% of dissolved gases.

Also, they remove particles as per the ISO 12/10/9, with flow rates varying from 1 to 200gmp.

When you visit their official website, you can choose your location to get a suitable vacuum dehydrator oil purification system.

7. Clark-Reliance

Clark Reliance is yet, another hydraulic dehydrator manufacturer that has been in the filtration industry for years. It provides many filtration accessories in mining, food processing, power generation, chemical processing, etc.

Some of its main filtration accessories include vacuum dehydrators, coalescing elements, filtration, etc.

Clark Reliance

Clark Reliance

Like other vacuum dehydrator oil purification systems, Clark Reliance vacuum dehydration oil purification system (VDOPS) remove water, gases and particulate.

Besides, they also come with granular adsorbent media that filters all varnish from turbine and hydraulic oil. In most cases, this comes as an optional accessory.

You can download their catalogue to learn more about Clark Reliance Vacuum Dehydrators.

8. High Purity Northwest

Among the main filtration equipment and accessories by High Purity Northwest includes thermo Vac oil purification systems, mobile oil purification systems and fuel filtration systems.

They come in a range of sizes, pressures and flow rates, depending on the specific needs of various applications.

High Purity Northwest

High Purity Northwest

Looking at High Purity Northwest oil filtration systems, you will see robust equipment that fit the dynamic oil purification requirements in most industries.

I want you to get this right:

These are not the only vacuum dehydrator manufacturers in the global market. I have just sampled some of the top manufacturers.

Form the habit of doing proper research and buying these accessories from reputable vacuum dehydrator manufacturers.

Before I summarize this vacuum dehydrator guide, here is a quick reminder:

You must not allow contaminated oil with water, gases, particulate or varnish reduce the life span of your machines or hydraulic fluids.

All you need is an effective and efficient oil purification system – that’s exactly what you have learnt here.

Now, it’s your turn:

Do you have problems in removing particulate matter, gases, varnish, acid or water in all its phases?

Well, I am here to help – feel free to leave a quick comment below.

You can also reach me via contact us form/email.

Still, in case you want to learn more about oil purification systems, here are more resources:

More Resources:

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