Hydraulic Proportional Valve

The importance of precision is paramount when it comes to fluid regulation from one point to another. Transporting over or under fluid amount alter the end product characteristics. Traditional hydraulic components lack this feature. You can use hydraulic proportional valves in this regard.

This article will help you understand the working, types, components, benefits, applications, etc., of hydraulic proportional valves. Sounds exciting? Let’s dive in deeper!

What is a Hydraulic Proportional Valve

As the name reflects, a “hydraulic proportional valve” is a valve. It serves a role specifically in hydraulic systems. With this valve, you can enjoy complete control over fluid direction, pressure, and flow. You can adjust these parameters proportionally or continuously as per electrical input signals.

A hydraulic proportional valve is not like a proportional valve. The main reason is that you can use proportional valves for broader applications, including electric or pneumatic transfer.

Advantages of Hydraulic Proportional Valves

Multiple pros exist for the hydraulic proportional valve. Some of the main pros are:

High Precision and Efficient

The efficiency and precision of the hydraulic proportional valve are unquestionable. You can enhance the system’s performance incredibly. This valve is highly suitable where accuracy is crucial.

Negligible Heat Generation

Besides continuous operation, you are not going to experience any heat generation with this valve. The sensors and automated operation prevent throttling and ensure smooth operation. The materials of the valves excellently conduct heat and lead to zero heat retention.

Good System Response

The hydraulic proportional valve ensures quick and precise adjustments of various flow parameters. This way, you can level up your system response where precision and quick responsiveness are paramount.

Unmatchable Safety

The hydraulic proportional valve ensures good safety and security. Embedded sensors play a great role in this regard. With hydraulic proportional valves, you can make the optimum supply of fluid without exceeding pressure and rate.

Working Mechanism of Hydraulic Proportional Valve

When you turn on the hydraulic proportional valve, the electric signal drives the solenoid. This solenoid, in turn, controls the spool movement.

The movement of the spool then induces specific displacement in the valve port. Through this displaced part, the compressed fluid flows forward. This is how a hydraulic proportional valve accurately and precisely controls the fluid flow.

Working Mechanism of Hydraulic Proportional Valve
Working Mechanism of Hydraulic Proportional Valve

Key Types of Hydraulic Proportional Valves

There are three types of hydraulic proportional valves:

Flow Control Valves

These hydraulic proportional valves serve to control the flow rate of the specific fluid. You can accurately and precisely control the flow of fluid in motors and hydraulic cylinders. For instance, you can set the flow rate to 35 liters per hour or 50 liters per hour. You can also set the custom flow rate.

Flow Control Valve
Flow Control Valve

Direction Control Valves

Direction control hydraulic proportional valves play a crucial role in directing the fluid in a specific direction. With these valves, you can direct fluid up, down, right or left, etc. You can find these valves in automation systems and machinery specific for industrial use.

Direction Control Valve
Direction Control Valve

Pressure Control Valves

The pressure control hydraulic proportional valve controls and maintains the specific pressure within the pipes/lines. This way, these valves prevent damage to the line because of overpressure. These valves play a great role in adding life to your hydraulic system.

Pressure Control Valve
Pressure Control Valve

Components of Hydraulic Proportional Valve

Multiple components make up your hydraulic proportional valve. Information highlighted on these components includes:

Body of Valve

The body of the valve refers to the exterior case. This case is responsible for containing all the components of the valve. It ensures sealing and structural support for effective valve functioning.


The role of the spool is to maintain pressure and flow under a specific limit. It is a moveable valve element.


The function of the solenoid is to offer essential force to facilitate the movement of the spool. Solenoid produces a magnetic field when they experience electric current. Because of this, it actuates spool motion.


The feedback sensors play a crucial role in monitoring the spool position. These sensors ensure the operation of the valve as desired.

Electric Connectors

Electricity controls the functioning of the hydraulic proportional valves. The electric connectors through plugs/pins ensure the supply of electric current to the valve.

Hydraulic Fluid Ports

These ports allow the hydraulic fluid to move in or out of the hydraulic proportional valve. Hydraulic ports have a direct connection with the hydraulic system.

Returning Mechanism (Spring)

Spring acts as a returning mechanism. Upon removal of the electric signal, the spool moves to its default location with the help of a spring.

Damping Components

Needle valve or orifices acts as the damping components. With these elements, you can control the changing effect of the valve. You can eliminate the jerky or sudden movements causing hydraulic system instability.

Components of Hydraulic Proportional Valve
Components of Hydraulic Proportional Valve

Limitations of Hydraulic Proportional Valves

Some of the notable limitations associated with the hydraulic proportional valves are here for your concern:

Higher Cost

Hydraulic proportional valves are costlier. This is because of precision engineering and intelligent technology. The features it offers also make it a unique solution to the traditional ones. This also adds up to its cost.

Level of Complexity

The electric controlling systems of the valve are what add to the complexity. Such a level of complexity leads you to require expert-level knowledge. for installation, troubleshooting, etc.

Factors to Consider While Selecting Hydraulic Proportional Valves

There are a few things which you need to pay attention to for a good selection of hydraulic proportional valve:

Determine Flow Rate

The first and foremost step while selecting hydraulic proportional valves is to determine its flow rate.

The common rule for transmitting material through a hydraulic proportional valve is to work between 60-80% open at the maximum required transmission rate.

Pressure You Need

Pressure depends upon how many lengthy pipelines are there to flow fluid from them. So, you should be clear about how much capacity of transmitting fluid is required.

If the pressure is not according to your requirement, either you have to change the capacity of the valve, or you have to add another valve if the length of the transmitting lines is greater.

Valve Size

Production depends upon the size of the wall. The size of the wall is the core step to understanding what your actual requirement is.

The valve should not be too small to transmit the required material properly, and in the same way, it should not be too large that the valve cannot make the pressure, and it will not transmit for further processing.

Level of Accuracy

The level of accuracy is monitored through the position of the spool. LVDT monitors are selected to send the actual position to the operator and then send an accurate signal to the solenoid.

It would be best if you kept in mind the level of accuracy of a hydraulic proportional valve before deploying or purchasing.

Troubleshooting Hydraulic Proportional Valves

The purpose of troubleshooting is to examine why something does not work as anticipated and describe the resolution of the matter.

Diagnostic Tools

You can use red, green, and yellow lights to find the troubleshooting. These lights are on an amplifier mounted with the hydraulic proportional valve.

Troubleshooting Steps

  • Turn on the electricity, enable the signal to be received, and the “On” light to be turned green.
  • Check the power supply and the amplifier connections if the light doesn’t turn on.
  • Check if the voltage is present. 24 volts should be indicated on an amplifier.
  • You will see a red light if the voltage is below a minimum number of volts.
  • It usually means there is a short anywhere. Check the power supply or wiring.
  • You will see a yellow light at the below part of an amplifier, which means the power supply is good.
  • If the yellow light is flaming and blinking when the hydraulic proportional valve is operational, this indicates loose wiring connections.
  • Immediately check all the cables connected to the amplifier and the power cable is also connected to the amplifier.

Where Can You Employ Hydraulic Proportional Valves?

Here are the key sectors and industries where you can employ hydraulic proportional valves:

Industrial Sector

The hydraulic proportional valves are quite suitable to employ in the industrial sector.

You can install this valve to regulate the fluid transmission of various industries like pesticides, chemicals, refineries, offshore companies, etc.

Automotive/Mobile Equipment

A large number of automotive mobile equipment are deploying hydraulic proportional valves. Example includes fire brigades, industrial fluid transmission automobile vehicles, etc.

Injection Moulding

Injection molding is a massive productivity process, especially in making solid plastic parts.

Hydraulic proportional valves are the key instruments in plastic injection molding machines.

You can deploy these valves on injection molding machines to get better output.

Gas and Oil Industry

The hydraulic proportional valve is the key necessity item in the whole mechanical installations of the gas and oil industry

To maintain the pressure of fluid in transmission lines, you can deploy these proportional valves for smooth operations.

Food Sector

You can use and deploy the hydraulic proportional valve in the food sector to deliver rheostat over water, air, and gases through a quick, extremely exact comeback.

And assist in rationalizing applications while carrying repeatable control and desired output.

In the food sector, a proportional valve delivers control to the food processing applications where output is not consistent.

Energy Generation

The hydraulic proportional valves are useful for generating energy.

For example, when a hydraulic proportional valve works, hydraulic energy can be converted into heat energy.

You can use this energy for cooling fluid as well.


You should be aware of what your actual requirement is to control either change in dimension, transmission fluid rate, or controlling pressure.

This should be followed by detailed information about the hydraulic proportional valve. You can easily consider the above information to select the perfect hydraulic proportional valve.

In addition, if you have any queries on some points, comment below or reach out, we would be happy to facilitate you!

More Resources:

Hydraulic Calculations – Source: TARGET HYDRAULICS

Hydraulics Valves – Source: IQS Directory

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