Hydraulic Pressure Gauge

Hydraulic Pressure Gauge

What is Hydraulic Pressure Gauge?

A hydraulic pressure gauge is a special equipment that measures and display pressure in hydraulic systems. Once you install this gauge, it will determine the exact pressure due to the hydraulic system.

With this pressure measurement system, you can easily avoid system damage due to excess pressure. They are therefore significant in ensuring that hydraulic systems operate at optimal temperatures to avoid system breakdown.

Key Components

  • Dial: It is regarded as the main component in hydraulic pressure gauges. The dial is responsible for recording the pressure of the fluid.
  • Fluid: The fluid on the other hand is a special component of the hydraulic pressure gauge systems. It performs numerous functions in the system. For example, it acts as a lubricant to the movable parts such as the spring pointer. Similarly, it acts as a shock absorber hence ensuring a favourable environment for the dial to rotate.
  • Reading Scale: The reading scale is calibrated with specific units such as PSI. It provides an area where the pointer/dial rests as a result measuring the pressure of the fluid.
Standard Guiding Hydraulic Pressure Test Gauge

Standard Guiding Hydraulic Pressure Test Gauge

Hydraulic pressure test gauges have a specific standard that guides them. Among these standards include ASME which is American in origin.

Furthermore, hydraulic pressure gauges are also guided by EN standards. This is a common standard used in bourbon pressure test kits.

The two standards however differ from each other significantly. For example, the EN standard utilizes Bar or BSP units in the measurement of pressure while the other hand ASME uses PSI. They also differ in other aspects such as functionality, connection size, and accuracy.

Some of the most common standards EN 472, EN 837-1, EN 837-2, and EN 837-3. Other rating include ASME B40.100 and IP rating.

Measurement Units for Hydraulic Gauge

Measurement units involved in hydraulic gauges include Pounds per square inch (psi), Bar and Pascal (Pa).

Most devices use psi while others use Bar. It is important to note that 700 Bar=1000psi

Measurement Units for Hydraulic Gauge

How to Read Pressure Measurement in Analogue Hydraulic Gauge

Reading pressure measurements in analog gauges might be complex. This is because they have both bar and psi scales. In this case, the inner scale shows the psi reading and vice versa.

You have to check the movement of the pointer. In presence of pressure, the pointer will move in a circular manner. As you read the position of the pointer, ensure your is perpendicular to the pointer. This is to avoid possible parallax error.

However, for digital pressure gauge, the process is quite straightforward. Usually, these pressure gauges have LCD display. They will display the pressure values and suitable units.

The highest value will depend on the pressure measurement range of the hydraulic gauge. For instance, the pressure range in this system is between 0-3000 psi. All types of pressure gauges fall within this bracket of measurement.

Function of Fluid in Pressure Gauge for Hydraulic Systems

The fluid in pressure gauge hydraulic systems serves as an important element that contributes to the general functioning of the system. For this reason, all hydraulic pressure gauges are designed with a pressure gauge chamber where the fluid is filled.

The liquid is responsible for absorbing shock therefore ensuring a favourable environment during vibration to avoid poor performance of the system. Notably, the most preferable liquid for this purpose is glycerine due to its ability to operate in a wide range of temperatures. For instance, it is estimated to operate between -5 degrees(F) and +145 degrees (F).

Similarly, the glycerine oil also serves other purposes such as acting as a lubricant for easy movement of movable parts of the pressure gauge. For example, the spring pointer constantly needs to be lubricated to ensure accuracy and precision.

Function of Fluid in Pressure Gauge for Hydraulic Systems

Hydraulic Pressure Gauge Working Principle

Hydraulic pressure gauges have a distinct working principle from other types of pressure gauges. However, the working principles in these types of pressure gauges differ from one another depending on their applications, type as well and purpose. The two common working principles used in hydraulic pressure gauges are bellows and bourdon tube gauges.

1. Bellows Working Principle

It utilizes an expandable and contractible spring. The spring is well-fitted to a graduated dial that enables it to measure the amount of pressure. In this instance, the spring contracts or expands depending on the amount of pressure exerted by the hydraulic fluids.

Frequent expansion and contraction of the fluid results creation of a significant amount of force. The force created is significantly important since it initiates the rotation of the rotary graduated dial. As the dial rotates, it points at the graduated scale hence resulting in reading the pressure of the fluids.

2. Bourdon Tube Pressure Gauge Working Principle

Bourdon tube working principle is a significant and common type of working principle among hydraulic pressure gauge systems. As opposed to the bellows working principle, bourdon tubes utilize flat-shaped tubes.

The flat-shaped tubes are conjoined on one end in that the end is joined to the hydraulic fluid through the entry point. However, the other end of the flat-shaped tube is sealed and allowed to freely rotate. As the tube rotates, it records the atmospheric pressure of the hydraulic fluid in the system.

Hydraulic Pressure Gauge Calibration Process

Step 1: Cleaning

This is the initial step in the pressure gauge calibration process. As such, this is an important step since it aids in removing any form of contamination that might interfere with the liquid hence altering the final reading.

Step 2: Checking for Leaks

The second step in the hydraulic pressure gauge calibration process entails running leak tests. Contacting leak test is important in this process since it eradicates the possibility of errors in the system. This is normally done by generating pressure and monitoring it after a given period.  In cases where leakages have been detected, urgent maintenance of the system is required.

Step 3: Testing the Pressure Gauge under Normal Working Conditions

In this step, the test device is put on exercise before commencing actual calibration. Movable parts are allowed to freely move to ascertain whether they are in good condition to provide reliable readings.

Stabilize Liquid in Pressure Gauge
Step 4: Stabilize Liquid in Pressure Gauge

This step involves the stabilization of the liquid pressure before reading the scale. This is the immediate process that follows after successfully conducting exercises on the device. In this step, the hydraulic pressure gauge test kit is tested for its effectiveness and accuracy.

Step 5: Set the Pointer and Make Appropriate Markings

The step entails setting the pointer and marking the commencement of the calibration process. The calibration should be made precise in that it can effectively determine the pressure in instances where the pointer rests in between two points.

Step 6 Check the Gauge a Final Time to Ensure there is no Friction
Step 6: Check the Gauge a Final Time to Ensure there is no Friction

This is the final step in the hydraulic pressure gauge calibration process. In this stage, the gauges are checked to ensure that don’t have any form of friction that can alter the pressure reading. Similarly, general cleaning of the device is done in this stage. This ensures the removal of any possible contamination during the calibration process.

Where to use Hydraulic Pressure Gauge

Construction Tools and Equipment
Construction Tools and Equipment

Hydraulic pressure gauge systems are commonly applied in construction equipment that have hydraulic systems. The majority of construction equipment utilizes hydraulic pressure gauges since they are hydraulically operated. For example, bulldozers, heavy trucks, cranes as well as excavators.

Hydraulic Pumps
Hydraulic Pumps

Hydraulic pumps have similarly utilized hydraulic pressure gauges for their effective operation. In this case, the pressure gauges measure the amount of pressure in the hydraulic pumps. The pressure recorded below or above the required pressure indicates the in-effectiveness of the system hence calling for urgent inspection and maintenance.

Hydraulic Presses
Hydraulic Presses

Industrial applications such as hydraulic presses utilize hydraulic pressure gauges. They significantly help in the determination of pressure within the system hence ensuring that the system operates at optimal pressure.

Control Systems
Control Systems

Control systems have also embraced hydraulic pressure gauges. As such, they are used in recording the pressure in actuator chambers during their operation. They play an important role in hydraulic pressure testing.

Hydraulic Pressure Gauge Types

The most common types include;

Digital Hydraulic Pressure Gauge

The knowledge and technology of hydraulic pressure systems have significantly improved in recent years. Digital hydraulic pressure gauge systems are among the latest innovations in this field.

In most cases, you can deploy these pressure measurement systems in high pressure applications. For instance, they can be used for measuring pressure exceeding 6050PSI to approximately 4300PSI.


Digital hydraulic pressure gauges possess numerous advantages over other types of hydraulic pressure gauge systems. Some of these advantages include but not limited to;

  • Suitable for applications that require high pressure.
  • Are compatible most hydraulic media.
  • Suitable for measuring pressure for a variety of hydraulic media including non-corrosive media.


Below are some of the basic features of digital hydraulic pressure gauge sensors.

  • Have high accuracy and precision in measuring the pressure of fluids.
  • High range of pressure of up to 4300 psi.


  1. Industrial applications such as petrochemical plants.

Analogue Pressure Gauge

Analog pressure gauges differ from digital hydraulic pressure gauges in terms of cost, functionality, and operational principle. In this case, they are less expensive as compared to digital hydraulic pressure gauges. This is attributed to their low functionality and performance ability.


  • Have a threaded connection.
  • They similarly have a back-bottom connection.
  • The dial size ranges from 65-100mm.
  • Are easy to operate and use.


  • They are cheap to purchase and maintain.
  • Are mechanical and hence do not necessarily depend on electricity to operate.
  • Easy to operate and read the measurements.

NB: Analogue hydraulic pressure gauge systems are majorly used in applications that require less pressure.

Wireless Hydraulic Pressure Test Kit

They are also referred to as wireless pressure test kits. Wireless hydraulic pressure kits significantly differ from other types of hydraulic pressure gauges in terms of their operation. In this case, they are automated and easy to operate hence efficient to use.


  • Are highly compatible
  • Have high accuracy and precision in the measurement of pressure.


  • They are expensive: Wireless hydraulic pressure test kits are generally inexpensive as compared to other types of pressure gauges. This explains why they are highly regarded by buyers.
  • Time-saving: They are termed to be time-saving in the sense that they carry out their operations within a limited amount of time. This is because they are automated.
  • Are labor-saving: These machines are automated and hence are not labor-demanding.

Electronic Hydraulic Pressure Gauge

Electronic hydraulic pressure gauges entirely depend on electricity to operate.


  • Are effective to use: They are powered by electricity and are fast hence effective to use.
  • Reliability: Electronic hydraulic pressure gauges are reliable in circumstances where there is a stable supply of electricity.


  • Are highly compatible with hydraulic media.
  • Suitable for measuring pressure for a variety of hydraulic media including non-corrosive media.
  • Are relatively less expensive.

How to Choose a Pressure Test Gauge

Choosing the best pressure test gauge for a particular purpose and function can be complicated. Therefore, various factors are required to be considered when choosing the most suitable pressure test gauges. Below are some of these factors;

· Temperature Considerations

To determine whether a particular pressure test gauge will suit your purpose, it is important to consider the range of temperature by which the pressure gauge can effectively operate. The range of temperature by which hydraulic pressure gauges operate differs significantly from one type to another.

For instance, standard hydraulic pressure gauges have a temperature operation range of around 150-180 Fahrenheit which is around 65-80 degrees Celsius. This explains why most hydraulic pressure gauges are commonly preferable in applications that require high temperatures.

· Range of Measurement

This is similarly an important aspect to be considered when choosing a suitable hydraulic pressure gauge for a certain purpose. It is significantly important for the buyer to know the minimum and the maximum amount of pressure that can be effectively measured by the gauge.

This is attributed to the fact that different applications have different amount amounts of pressure exerted that require measuring. For example, applications that involve the production of less amount of pressure should be fitted with pressure gauges that can accurately measure low pressure and vice versa.

· Type of Connection and Size

Hydraulic pressure gauges come in different sizes hence the difference in the type of connection from one type to another. It is therefore necessary for buyers to consider the right size of hydraulic pressure gauge that fits their purpose.

Small-sized hydraulic pressure gauges require small-sized connections and vice versa. On the other hand, the type of connection should also be carefully considered. For instance, the most notable type of connection applied in most hydraulic pressure gauges is a threaded connection.

· Fabrication and Connection Material

The type of material used in connection and fabrication of hydraulic pressure gauge system differs significantly depending on their purpose. For instance, the most common materials used in the fabrication of most hydraulic pressure gauge systems are alloys of carbon, brass, steel as well as copper.

Such materials are most preferred due to the improved properties they offer such as durability, compatibility, and their non-corrosive nature. Choosing the best connection material on the other hand depends on the compatibility of the material with the material used in the fabrication process.

· IP Protection

IP protection is a factor that should considered when choosing hydraulic pressure systems. A good hydraulic pressure gauge system should guarantee IP protection, especially during unfavorable operating conditions such as extreme temperatures, dust as well as humidity.

However, IP ratings in hydraulic pressure gauges differ significantly from one type to another. This also affects the pricing aspect of these systems. In this instance, pressure gauges with high IP ratings attract high prices while those with low IP ratings are less expensive.

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