Pressure and vacuum gauges

Measurement technology - measurement technology elements for pressure measurement

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Measuring fittings designed for fluid power pressure measurement. The category below contains elements intended for measuring pressure in hydraulic systems. Measurement technology in the field of pressure measurement is a field dealing with methods, tools and devices enabling precise determination of pressure values in hydraulic, pneumatic or other technical systems. Thanks to appropriate measuring instruments, it is possible to monitor the installation's operating parameters on an ongoing basis, which ensures safety, efficiency and correct operation of systems. Application of pressure measurement: Pressure measurement is key in many industries, such as: Power hydraulics: Pressure control in lines, pumps, cylinders and other installation elements. Pneumatics: Measurement of compressed air pressure in pneumatic tool and machine systems. Diagnostics and service: Fast and accurate checking of pressure parameters to detect potential faults.

Glycerine pressure gauges, dry, vacuum gauges 

Bottom entry pressure gauges (e.g. bottom 63 mm, bottom 100 mm): Designed for pressure measurement in systems, mounted vertically to ensure convenient reading. Back entry pressure gauges (e.g. back 63 mm, back 100 mm): Ideal for mounting on control panels or in places requiring reading in a horizontal position. Dry pressure gauges: Economical, lightweight and reliable devices for standard applications where extreme working conditions do not occur. Panel mount pressure gauges: Used in control panels, allowing for easy pressure monitoring in systems. Vacuum gauges: Enable measurement of negative pressure in systems such as suction or vacuum systems. Accessories for pressure gauges: Additional elements such as gauge covers or adapters that increase the durability and functionality of measuring devices. T-pieces with pressure gauge: Allow for simultaneous monitoring of pressure at different points of the hydraulic system.

What is a pressure gauge

What is a hydraulic pressure gauge? Hydraulic pressure gauges are measuring devices used to monitor liquid pressure in hydraulic systems. They are an indispensable element in systems of power hydraulics, where precise pressure control is necessary to ensure safety, efficiency and long life of installation elements. These gauges are often equipped with various connections and measurement ranges to adapt to specific industrial requirements. They are used in the machinery, construction, automotive and power industries. A hydraulic pressure gauge is a special type of pressure gauge designed specifically for work in a hydraulic environment, where the measured medium is most often hydraulic oil. It is distinguished by its strength and resistance to high pressures typical for this type of installation (even up to 700 bar). Hydraulic pressure gauges are used in devices such as presses, actuators, cranes or construction machinery to ensure precise control of loads and technological processes.

Bourdon tube

What is a Bourdon tube? The Bourdon tube is a key structural element used in most mechanical pressure gauges. It is a thin-walled, curved tube with an oval cross-section that straightens under the influence of internal pressure. The movement of the tube is transmitted to the pressure gauge pointer via a mechanical system. The Bourdon tube is characterized by: Precision: Enables accurate pressure measurement. Resistance: Made of metal alloys resistant to the medium, such as brass, stainless steel or Inconel. Versatility: Used in a wide range of pressures from low to very high (even above 1000 bar). 

Glycerine pressure gauge

Glycerine pressure gauge is a type of pressure gauge whose interior is filled with glycerine or another damping liquid. Such a construction provides: Damping of oscillations and vibrations: The liquid prevents rapid movements of the pointer in case of pressure pulsations. Increased durability: Protects the internal mechanism from wear in difficult working conditions, such as vibrations and shocks. Protection against condensation: Glycerine filling prevents the formation of moisture and corrosive atmospheres inside the device. Glycerine pressure gauges are used in industrial environments where dynamic pressure changes, shocks or vibrations occur, e.g. in construction machinery, hydraulic and pneumatic systems, as well as in cooling systems.

Hydraulic pressure meter 

A hydraulic pressure meter, also known as a hydraulic pressure gauge, is a device used to measure liquid pressure in power hydraulic systems. It is an essential tool in systems where precise pressure control is key to safety and operational efficiency. Most hydraulic pressure gauges are based on a Bourdon tube mechanism. Under the influence of pressure, this tube deforms, and its movement is transmitted to a pointer that shows the pressure value on a scale. To increase resistance to vibrations and shocks, many models are filled with liquid, which damps oscillations and ensures a stable reading.

Hydraulic gauge

A hydraulic gauge, also called a hydraulic pressure gauge, is one of the basic pieces of equipment in power hydraulic systems. Its task is to precisely measure the working pressure in the installation, which allows for monitoring system operation, early detection of abnormalities and ensuring the safety of operators and machines. The hydraulic gauge is mounted in both industrial and mobile machines, in cylinders, power units, hose crimping machines, presses and test systems. In practice, it is an essential tool wherever work is done with high hydraulic oil pressure.

Application of a hydraulic gauge

A hydraulic gauge is used in places requiring continuous pressure control. It can be mounted directly on pumps, valves, distributors, flexible hoses and hydraulic blocks. In construction and agricultural machinery systems, it allows for load control and prevents overloads that could lead to damage of cylinders or pumps. In workshops and service centers, gauges are used in test stands, diagnostic devices and when checking pressure in lines and power hydraulic components.

Construction of a hydraulic gauge

A hydraulic gauge consists of a metal housing, usually steel or brass, a measuring dial with a scale, a spring mechanism and a connection port used to connect it to the system. The gauge mechanism works based on a Bourdon-type tube spring, which deforms under pressure and transmits the movement to the pointer on the dial. The construction of the gauge must ensure resistance to vibrations, pressure pulsations and high loads typical for power hydraulics.

Parameters of a hydraulic gauge

When choosing a hydraulic gauge, several basic technical parameters should be considered. The most important is the measuring range, which should be adapted to the system's working pressure, most often ranging from several dozen to even 700 bar. Proper execution of the connection port, its thread, diameter and mounting direction are also important. The accuracy class of the gauge, which determines reading precision, is also significant. Models used in professional hydraulic systems are often equipped with glycerine to damp pointer vibrations, ensuring a stable and legible measurement even in difficult conditions.

Types of hydraulic gauges

Various types of gauges adapted to specific working conditions are used in hydraulic installations. Dry gauges, intended for simple systems, and glycerine gauges used in applications subjected to high vibrations are available. Panel gauges mounted in industrial devices and gauges with a color scale, facilitating quick determination of the system load, are also encountered. In mobile hydraulics, compact gauges resistant to shocks and changing environmental conditions are often used.

Measuring test points, fittings, measuring lines 

Measuring test points: Used for quick and safe connection of pressure gauges to the installation, facilitating diagnostics and service. Pressure gauge fittings: Ensure a durable and tight connection of measuring devices with the system. Measuring lines: High-strength flexible lines connecting pressure gauges with measuring points in the installation. They are resistant to high pressures and difficult working conditions. Measuring kits: Ready-made solutions containing all necessary elements for precise pressure measurement, such as pressure gauges, lines and test points.

Why is it worth choosing the HYDRON offer?

Thanks to a rich offer of pressure gauges, vacuum gauges, connections and accessories, HYDRON provides solutions that meet the needs of both professionals and smaller users. These devices are characterized by high quality, precision and reliability, and the wide range allows for matching products to various applications.

How to measure pressure in a hydraulic system? 

Many people are puzzled by the question of how to measure pressure in a system (hydraulic, water, air, etc.)? The answer is simple: we must plug into the hydraulic system using certain elements. The following elements can be used to plug in and measure pressure: pressure gauge (this is available with a back or bottom connection, depending on the connection possibilities we have). Standard pressure gauges have a dial with a diameter of 63mm, measurement range: from vacuum up to 1000bar, pressure gauges are filled with glycerine, making them resistant to shocks - the pressure gauge will not be damaged during vibrations. Measuring line (using a measuring line, we can connect a pressure gauge with a gauge connection). Measuring lines come in various configurations: a standard line is a hose equipped on one side with a connection called minimess (with M16x2 thread) and on the other for a pressure gauge (1/4" internal thread). Other versions are minimess-minimess on both sides or 1/4" on both sides. Measuring test point. A measuring test point is a fitting plugged (connected) on one side into the system (e.g. to a machine housing element) and on the other side most often equipped with an M16x2 (minimess) thread. The measuring test point is a kind of quick coupler through which we can quickly connect a measuring line with a pressure gauge. 

Devices designed for pressure measurement in hydraulic systems

The offer includes a wide range of pressure measuring instruments commonly known as manometers. We have pressure gauges glycerine-filled pressure gauges, radial (connection at the side of the housing), axial (connection at the back of the housing), with 1/4" BSP or 1/2" BSP threads scaled in bars and psi with an accuracy class of 1.6. Glycerine pressure gauges in a stainless steel housing with pressures from 1 to 1000 bar, dial diameters: 63mm (m63 pressure gauge) and 100 mm. We also offer measuring hoses and connectors. There are many different pressure measuring devices used in various industries and applications. Here are some examples of popular pressure measuring devices: 

Pressure gauge 

Pressure gauge is the most basic device for pressure measurement. It consists of a dial with a pointer and a scale on which the pressure value is read. Pressure gauges can be analog or digital and have different measuring ranges depending on needs. A pressure gauge is a commonly used device for measuring pressure. It consists of a dial with a pointer that indicates the current pressure and a scale on which the measurement value is read.

Pressure gauges 

Pressure gauges are available in various types and measuring ranges, depending on the specific application. Pressure gauges can be analog or digital. Analog pressure gauges have a traditional dial with a pointer that moves due to the action of pressure. The dial scale is divided into pressure units such as psi (pound per square inch), bar, MPa (megapascal) or kPa (kilopascal). The pressure value is read on the pointer indicating the corresponding value on the scale. Digital pressure gauges, also called electronic pressure gauges, have a digital display on which the pressure value is presented numerically. They often have additional functions such as the ability to set pressure units, data logging, alarms or communication with other devices. Pressure gauges are widely used in various fields such as industry, hydraulics, pneumatics, food industry, HVAC (heating, ventilation and air conditioning), medicine, oil industry and many others. They are an essential tool for monitoring, diagnostics and pressure control in various processes and systems. When choosing a pressure gauge, the measuring range, accuracy, tolerance, type of connection (e.g. threaded, T-piece, clamp) and compliance with industry standards and norms should be taken into account.

Pressure gauges compliant with EN 837-1

Standard EN 837-1 concerns Bourdon tube pressure gauges. The EN 837-1 standard specifies technical requirements for spring pressure gauges used to measure liquid and gas pressure. It is the first part of the EN 837 standard, which concerns Bourdon tube pressure gauges – one of the most commonly used types of measuring instruments in industry. The scope of the EN 837-1 standard includes: 1. Construction and dimensions of pressure gauges – standard diameter ranges, connection threads and types of measuring mechanisms. 2. Measurement accuracy – defines pressure gauge accuracy classes (e.g. class 0.6; 1.0; 1.6; 2.5). 3. Materials used in production – considers resistance to working media and environmental conditions. 4. Measuring ranges – defines the pressure values that can be measured by pressure gauges compliant with the standard. 5. Operational safety – specifies requirements regarding the resistance of pressure gauges to overloads and environmental influences. Why is EN 837-1 important? This standard guarantees that pressure gauges used in hydraulic, pneumatic, chemical and other industrial applications meet specified quality and safety standards. Thanks to this, users can be sure that pressure indications are precise and devices are resistant to the action of pressure working factors.

How does a pressure gauge work? 

How does a pressure gauge work? A pressure gauge is a measuring instrument used to measure the pressure of liquids or gases. Its operation is based on the principle that the pressure exerted by a liquid or gas causes deformation of a measuring element, which is then converted into a readable result on the pressure gauge scale. How does it look in practice? The most common type of pressure gauge is a spring (tube) pressure gauge, called a Bourdon pressure gauge. Inside it is a curved, flexible tube (Bourdon tube). When the pressure increases, the tube begins to straighten. This deformation is transmitted to a pointer that shows the current pressure on the scale. Where are pressure gauges used? Pressure gauges are used wherever pressure control is important – in hydraulics, pneumatics, gas, water and air conditioning installations. They are also used in the food, chemical and automotive industries. Types of pressure gauges - depending on the application, several types of pressure gauges can be distinguished:

• Mechanical pressure gauges – most commonly used in hydraulics, pneumatics and industrial installations.
• Glycerine pressure gauges – filled with glycerine, making them resistant to vibrations and sudden pressure jumps.
• Digital pressure gauges – display the result on an LCD screen, providing very accurate measurement.

Types of pressure gauges - division of pressure gauges: 

• pressure gauges with bottom connection (bottom gauges)
• pressure gauges with back connection (back gauges)
• panel mount pressure gauges (for mounting in a housing)
• pressure gauges with 1/4 (standard), 1/2 thread
• pressure gauges with 63mm (standard), 100mm diameter 
• vacuum gauges (measuring negative pressure)

Hydraulic pressure meter

What is a hydraulic pressure meter? A hydraulic pressure meter, also known as a hydraulic pressure gauge, is a device used to measure the pressure of working liquid in power hydraulic systems. It is an essential element of hydraulic systems, used in diagnostics, maintenance and ongoing monitoring of machine and installation operating parameters. Thanks to its use, one can precisely monitor pressure in the system, allowing for the detection of potential problems such as pressure drops, leaks or system overloads. 

How does a hydraulic pressure meter work? 

Hydraulic pressure meters work on the principle of deformation of a measuring element under the influence of liquid pressure. In most cases, mechanical pressure gauges are used, which utilize a Bourdon tube – a thin-walled, elastic tube that bends under the influence of pressure changes, which is converted into indications on the device's scale. In hydraulic systems, glycerine pressure gauges are also encountered, which, thanks to glycerine filling, reduce vibrations and protect the measuring mechanism from damage.

Pressure in kPa, bar and mbar – how to read pressure gauge indications?

In hydraulic, pneumatic or industrial installations, precise pressure measurement is a key element ensuring safety and effective system operation. That is why it is so important to select the appropriate pressure gauge and understand the units in which pressure is expressed. The most common are kPa, bar and mbar. What do these units mean and how to convert them? 

What are pressure units – kPa, bar, mbar?

• kPa (kilopascal) – a unit from the SI system, commonly used in industry. 1 kPa = 1000 Pa.

• bar – a unit often used in Europe, especially in hydraulics. 1 bar = 100,000 Pa = 100 kPa.

• mbar (millibar) – a smaller unit, often found in devices for measuring very low pressures (e.g. vacuum gauges, HVAC systems). 1 bar = 1000 mbar.

It is worth remembering basic conversions:

• 1 bar = 100 kPa = 1000 mbar

• 1 kPa = 0.01 bar = 10 mbar

• 1 mbar = 0.1 kPa = 0.001 bar

Why do pressure gauges show pressure in different units?

Various types of pressure gauges are available on the market – depending on the application, they can show pressure in one or several units. The Hydron offer includes pressure gauges and vacuum gauges in versions with a scale: single (e.g. only bar or only kPa), double (e.g. bar + psi, bar + kPa, mbar + mmHg) – which enables convenient reading in different applications. Unit selection depends among others on: the industry (e.g. in power hydraulics bar is the standard), working pressure level (for low pressures mbar or kPa work better), user preference or machine manufacturer.

Practical application of pressure gauges with different units

• Pressure gauges for power hydraulics – most often have a scale in bars (e.g. 0–400 bar), because hydraulic systems usually work under high pressure.
• Pressure gauges for pneumatics – can show pressure in bar, kPa or psi, depending on the application.
• Vacuum gauges – often equipped with a scale in mbar, because they measure negative pressure (e.g. -1000 to 0 mbar).
• Pressure gauges for laboratory or HVAC applications – use scales in mbar or Pa to precisely determine low pressures.

Other measuring elements from our offer: 

• measuring test points (connecting the measuring line)
• pressure gauge connectors (pressure gauge thread reduction)
• pressure gauge covers (protection against mechanical damage)
• measuring kits (ready-made kits for measuring pressure in the system with various gauges)

Pressure transmitter: A pressure transmitter is an electronic device that measures pressure and transmits an electrical signal or an analog signal based on this value. Pressure transmitters are widely used in industry, and their signal can be used for monitoring, control and recording pressure data. 

Pressure transducer: A pressure transducer is a device that converts a pressure signal into an electrical or pneumatic signal. It is often used in automatic control systems where a pressure signal must be converted into a corresponding control signal.

Barometer: A barometer is a device for measuring atmospheric pressure. Atmospheric pressure measurement is important in many fields such as meteorology, navigation and environmental research.

Pressure sensor: A pressure sensor is a device that records pressure changes and generates a corresponding electrical signal. It is widely used in many applications such as the automotive industry, chemical industry, petrochemical industry and others.

These are just a few examples of pressure measuring devices. There are many other specialized devices adapted to specific applications. Choosing the right pressure measuring device depends on the type of measurement, the measuring range, the precision required in the application and other factors specific to a given industry or application.

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Check also:

• Download: Pressure gauge datasheet
• How to choose the right pressure gauge and vacuum gauge for your application
• Diagram of connecting a pressure gauge to a system
• Pressure gauges RACCORDI MANOMETRI