Pressure gauge with back entry 

What are back-entry pressure gauges and what are they used for ? 

Back-entry pressure gauges, also known as axial connection gauges (axial), are devices used for precise pressure measurement in various systems, such as hydraulic, pneumatic, or industrial systems. Due to their design with the connection located at the back of the housing, axial gauges are widely used where the mounting space requires the device to be installed perpendicular to the surface. Pressure gauges ( pressure gauges ) with back entry - where the thread is located at the rear of the pressure gauge. Back-entry pressure gauges are the second most common type of pressure gauges ( alongside bottom-entry pressure gauges ) The main task of pressure gauges is to measure pressure ( hydraulic oil, gas, liquid, water ) in the system.  Glycerin-filled pressure gauges. Standard Bourdon tube pressure gauges are filled with glycerin, making them vibration-resistant. Glycerin protects the pointer from mechanical damage.

Axial pressure gauge

The word „axial” refers to the axial arrangement of the connection relative to the gauge body, which means that the connection is located on the symmetry axis of the rear part of the device. This is particularly important in places where the pressure gauge is mounted on panels, control boards, or in special housings, providing easy access to reading the results. Characteristics of back-entry pressure gauges. Back-entry pressure gauges are distinguished by a specific design and features that allow their use in various operating conditions: Back (axial) connection: Located at the back of the housing, which allows for the mounting of the device in a vertical or axial configuration. These gauges provide precise pressure measurement, which is crucial in applications requiring accurate data about the system state. Often made of stainless steel or other durable materials, which makes them resistant to harmful external factors such as moisture, chemicals, or vibrations. A large dial and clear markings ensure easy and quick value reading. Available in various measurement ranges, allowing the selection of the appropriate pressure gauge for the specific system.

Axial vs. radial pressure gauge

A comparison between an axial and radial pressure gauge concerns the method of connecting the pressure gauge to the installation, not the pressure measurement function itself. Both types of gauges measure pressure in an identical way, but they differ in the position of the threaded connection, which has a direct impact on mounting, ergonomics, and application in hydraulic and pneumatic installations. The choice between an axial and radial pressure gauge should result from the mounting location and the direction from which the scale is to be read.

Where are back-entry pressure gauges used ?

Back-entry pressure gauges are widely used in many industries, including: Power hydraulics: Monitoring pressure in hoses and hydraulic systems. Industry: Pressure control in machines, production systems, and technological installations. Pneumatics: Precise pressure measurement in compressed air and technical gases. Water and sewage systems: Pressure measurement in water supply systems and pumps.
Control boards: Mounting on control panels for easy monitoring of parameters. 

Why choose pressure gauges at the Hydron store ?

Hydron offers high-quality back-entry pressure gauges that combine precision, durability, and reliability. We cooperate with renowned manufacturers, ensuring our products meet the highest quality standards. In our offer, you will find a wide selection of pressure gauges tailored to various pressure ranges and specific technical needs. Our devices are certified, which guarantees their compliance with safety and accuracy standards. When buying from Hydron, you can count on professional advice from our team, who will help you choose the right product for your applications. Order now and improve the performance of your systems with the help of reliable pressure gauges! 

Other pressure measurement assortment 

In our offer, we have pressure gauges with dial diameters of 40, 50, 63, and 100. In scales from 0.5 - 2000 bar. Glycerin-filled pressure gauges. In our offer, we also have bottom-entry pressure gauges, panel-mount pressure gauges, test points, and complete pressure measurement kits.  

Pressure gauges compliant with the EN 837-1 standard 

The EN 837-1 standard is a European technical standard that precisely defines the requirements for Bourdon tube spring pressure gauges, which are the most commonly used instruments for measuring pressure in power hydraulics, pneumatics, and the broadly defined industry. It is the basic standard encountered by every user of pressure gauges used for controlling the pressure of oil, air, water, and other non-aggressive media. EN 837-1 defines both the construction of the pressure gauge and its performance parameters, thanks to which devices marked with this standard provide repeatable, safe, and reliable pressure measurement. This standard is of great importance in hydraulic installations, where a correct pressure reading directly affects the durability of hoses, fittings, pumps, and valves.

Scope of the EN 837-1 standard

The EN 837-1 standard covers spring pressure gauges in which the measuring element is a Bourdon tube. During a pressure increase, this tube deforms, and the mechanism transmits the movement to the pointer, showing the current pressure value on the dial. The standard defines permissible measurement ranges, which can reach from very low values to several hundred or even a thousand bars, which makes these pressure gauges suitable for both pneumatics and power hydraulics. EN 837-1 also regulates measurement accuracy classes, most commonly encountered in workshop and industrial practice, such as 1.0, 1.6, or 2.5. The lower the class value, the greater the measurement accuracy, which is particularly important for diagnosing hydraulic systems and adjusting pressure valves.

EN 837-1 compliant pressure gauges in practice

Pressure gauges meeting the requirements of EN 837-1 are commonly used in construction and agricultural machinery, industrial lines, hydraulic power units, and pneumatic installations. The standard allows both dry pressure gauges, as well as glycerin-filled pressure gauges, which, thanks to the liquid filling, dampen vibrations and pressure pulsations. This is particularly important in power hydraulic systems, where pressure often changes dynamically. An essential part of the standard is also the requirements regarding dial diameters, mounting methods, and resistance to overloads. Thanks to this, EN 837-1 pressure gauges can be used safely even in difficult operating conditions where vibrations, pressure spikes, and variable temperatures occur.

Why the EN 837-1 standard is so important in hydraulics

The use of pressure gauges compliant with EN 837-1 increases the safety of the entire hydraulic system. Accurate pressure measurement allows for the quick detection of abnormalities, prevents damage to hydraulic hoses and fittings and protects expensive installation components. This standard is also a confirmation of the pressure gauge's manufacturing quality and compliance with European technical requirements, which is important in both industrial and service applications. In practice, the EN 837-1 marking on the pressure gauge is clear information that the instrument was designed with reliable and safe pressure measurement in mind, in accordance with the current standards used in power hydraulics and pneumatics.

How to choose a pressure gauge ? 

Choosing the right pressure gauge has a direct impact on the safety of the installation, correct diagnostics, and the durability of system components. Although a pressure gauge is a simple measuring instrument, its incorrect matching very often results in wrong readings, rapid wear of the mechanism, or damage resulting from overloads.

Measuring range of the pressure gauge

The most important criterion when choosing a pressure gauge is its measuring range. A pressure gauge should not operate at the extreme values of the scale, as this negatively affects the accuracy and life of the device. In practice, it is recommended that the operating pressure of the installation falls within a range of about one-third to two-thirds of the full scale. For a system operating at a pressure of 160 bar, a reasonable choice will be a pressure gauge with a 0–250 range or a 0–300 bar pressure gauge, which will ensure a clear reading and safe operation of the measuring element.

Measurement accuracy

Another significant aspect is measurement accuracy, which defines the permissible indication error. For service, workshop, and industrial applications, standard accuracy is usually sufficient, providing a stable and repeatable reading. In the case of control, regulation, or diagnostic measurements, it is worth using pressure gauges with increased accuracy, which allow for precise setting of system operation parameters.

Dry or glycerin-filled pressure gauge

The choice between a dry and a glycerin-filled pressure gauge depends on the installation's operating conditions. In systems where vibrations, pressure pulsations, or dynamic parameter changes occur, glycerin-filled pressure gauges perform much better. Filling the housing with glycerin dampens pointer vibrations, improves readability, and extends the durability of the mechanism. Dry pressure gauges are suitable for stable operating conditions where the pressure changes gently and no vibrations occur.

Type of connection and pressure gauge thread

When choosing a pressure gauge, attention should be paid to the method of its installation. The most common are bottom-entry pressure gauges or back-entry ones, and the choice depends on the installation design and available space. Equally important is the type and size of the thread, which must be compatible with the connection in the system. In practice, inch threads are most commonly used, such as 1/4, 3/8 or 1/2 inch pressure gauges, found in both hydraulics and pneumatics.

Dial diameter and readability

The pressure gauge dial diameter directly affects reading comfort. Smaller dials are used where compact installation matters, while larger diameters provide better visibility of indications from a greater distance. In stationary installations and on diagnostic stands, a larger dial facilitates ongoing pressure control and reduces the risk of misinterpreting the reading.

Operating conditions and environment

The last but very important element of pressure gauge selection is the environmental conditions. One must consider the operating temperature, humidity, potential for vibrations, and contact with the working medium. In difficult operating conditions, it is worth choosing pressure gauges with a reinforced structure, resistant to vibrations and variable temperatures, which translates into longer and safer operation.

Why the correct selection of a pressure gauge matters

A correctly chosen pressure gauge is not only an accurate pressure measurement but also an effective control and protection tool for the entire system. The appropriate range, correct accuracy, and matching to operating conditions allow for quick detection of abnormalities, prevent failures, and ensure the safe functioning of hydraulic and pneumatic installations.

The pressure gauge class is a parameter defining the accuracy of pressure measurement, specifically the maximum permissible indication error that may occur during the pressure gauge's operation. Information about the class is always given on the pressure gauge dial and expressed as a number, for example 1.0, 1.6, or 2.5. The lower the class value, the more accurate the measurement and the smaller the deviation of the indication from the actual pressure in the installation.

What pressure gauge class means in practice

The pressure gauge class defines the maximum error as a percentage of the full scale range, rather than the current indication. This means that the error is always calculated from the maximum value on the pressure gauge dial. For example, for a pressure gauge with a range of 0–250 bar and a class of 1.6, the permissible error is ±1.6% of 250 bar, which is ±4 bar. Regardless of whether the gauge indicates 50, 100, or 200 bar, the maximum error refers to the full scale.

Most common pressure gauge classes

In hydraulic and pneumatic practice, several accuracy classes are most commonly encountered. Class 2.5 is used in simple installations where the measurement is approximate and serves mainly to check for the presence of pressure. Class 1.6 is the most universal solution, often used in power hydraulics, workshops, and services. It provides a good balance between accuracy and mechanical resistance. Class 1.0 is intended for applications where greater precision is required, for example, when adjusting valves, pressure tests, or system diagnostics.

Why the pressure gauge class matters

Choosing the right pressure gauge class has a direct impact on the safety and correct operation of the installation. Too low accuracy can lead to an incorrect assessment of pressure, which in power hydraulics can result in overloading hoses, fittings, or pumps. On the other hand, very high accuracy is not always necessary and often means a higher purchase cost that does not translate into real benefits in simple applications.

Where to check the pressure gauge class

The pressure gauge class is always marked on the dial, usually in the lower part or near the center of the scale. It may be written as a single number, for example 1.6, or as an abbreviation with a percentage symbol. In the case of industrial pressure gauges, this information is one of the basic technical parameters and allows for a quick assessment of which applications a given model is intended for. Understanding what a pressure gauge class is allows for the conscious selection of the appropriate measuring instrument and avoids errors that can lead to incorrect operation or damage to the entire system.

Useful information : 

• back-entry pressure gauges data sheet
• pressure gauges installation instructions
• how to correctly install a glycerin-filled pressure gauge

Gallery: