Presseure gauges / manometers Manufacturers online

Pressure gauges/manometers are used to record and display the pressure of liquids, gases or mechanical pressures.

A distinction is made between direct and indirect pressure gauges.

Below you will find an overview of the functions and types of direct and indirect pressure gauges as well as a brief overview of their areas of application:

How pressure gauges work:

Direct pressure gauges measure pressure directly by mechanical deformation or displacement of a measuring element.
They do not require any electrical or electronic conversions, which makes them particularly robust and reliable.

These pressure gauges use elastic elements for direct pressure measurement.

1. Bourdon tube pressure gauge (Bourdon tube):
   Functional principle: A curved metal tube expands when the pressure rises, the movement is transmitted to a scale.
   Features: Very robust and reliable. Suitable for high pressures (up to several 1000 bar).
   Applications: Mechanical engineering, hydraulic systems, gas pressure measurement.
2. Diaphragm pressure gauge:
   Functional principle: A flexible metal diaphragm deforms depending on the pressure and transmits the movement to a scale.
   Features: Well suited for low pressures and aggressive media. High resistance to vibrations.
   Applications: Medicine, chemical industry, environmental technology.
3. Bulb pressure gauge:
   Functional principle: A thin-walled metal capsule deforms under pressure changes and moves an indicator.
   Features: Sensitive to low pressures. Often used for differential pressure measurements.
   Applications: Air pressure measurement (barometer), filter monitoring.
4. Piston pressure gauge (pressure compensator):
   Functional principle: The pressure acts on a piston with a defined area, which is pressed against a known mass.
   Features: High accuracy due to direct mechanical measurement. Often used as a calibration instrument.
   Applications: Precise pressure measurements in research and calibration technology.
5. Liquid column manometer:
   Functional principle: The pressure is represented as the difference in height of a liquid column.
   Types:
   U-tube manometers: Two connected tubes in which a liquid (e.g. mercury or water) moves.
   Inclined tube manometer: For small pressure differences with higher reading accuracy.
   Simple tube manometer: An open column with liquid that moves according to the pressure.
   Applications: Laboratories, calibration, differential pressure measurement.

Indirect pressure gauges do not measure the pressure directly, but detect a physical change (e.g. a force or electrical resistance) caused by the pressure. Indirect measurement enables high precision and is often suitable for demanding applications.

These pressure measuring devices convert pressure into electrical signals and are particularly suitable for industrial applications.

1. Strain gauge (DMS) sensors:
   Functional principle: A thin metal strip with an electrical resistance is applied to a diaphragm. Pressure changes the resistance value.
   Features: Very accurate, robust, suitable for high pressures.
   Applications: Mechanical engineering, automotive engineering, hydraulic systems.
2. Piezoelectric pressure sensors:
   Functional principle: Piezoelectric crystals generate an electrical voltage when they are deformed by pressure.
   Features: Ideal for dynamic pressure measurements, fast response time.
   Applications: Shock and vibration measurement, combustion engines, aerospace.
3. Capacitive pressure sensors:
   Operating principle: Pressure changes the distance between two capacitor plates, which changes the capacitance.
   Features: Very sensitive, suitable for low pressures.
   Applications: Medicine, microelectronics, air pressure measurement.
4. Resonant pressure sensors:
   Operating principle: The pressure influences the resonance frequency of a mechanical element.
   Features: Very high accuracy, long service life.
   Applications: High-precision laboratory applications, space travel, weather stations.
5. Liquid column manometers:
   Functional principle: The pressure is represented as the difference in height of a liquid column.
   Types: Mercury, water or oil column manometers.
   Applications: Calibration, laboratory environments.
6. Immersion probes:
   Operating principle: The pressure of the liquid column above the probe is used for measurement.
   Features: Ideal for level measurement.
   Applications: Tanks, groundwater level measurement.
7. Fiber optic or reflection pressure sensors:
   Operating principle: Light is influenced by an optical fiber or reflection.
   Features: High accuracy, insensitive to electromagnetic interference.
   Applications: High-voltage systems, medical technology.

Use of pressure gauges:

1. Industry and production:
monitoring of process pressures in machines and systems.
Checking hydraulic and pneumatic systems.
Quality testing through pressure testing.

2. Medicine and healthcare:
Blood pressure monitors for humans.
Measurement of ventilation pressure in intensive care medicine.

3. Automotive engineering:
Tire pressure sensors for vehicle safety.
oil and fuel pressure sensors for engine monitoring.

4. Environmental and weather technology:
Barometers for weather forecasting.
Air pressure measurement for high and low altitude applications.

5. Aerospace:
Altimeters in airplanes
Pressure measurement in rocket and satellite systems.

Pressure measuring devices are essential tools in many areas, from industry and medicine to aviation. Choosing the right pressure sensor depends on the type of medium, accuracy and environmental conditions.

Below is an overview of the most important points to consider when purchasing pressure gauges:

Purchasing pressure gauges requires careful analysis of various factors to ensure that the device meets the requirements of the application.

• Before purchasing pressure gauges, the specific requirements must be analyzed carefully to ensure that the right device is purchased for the measurement task:
• Choose a device that covers the expected pressure range.
• Take into account safety margins, e.g. 25-50 % above the expected maximum pressure.
• Typical pressure ranges are: Vacuum, low pressure, medium pressure, high pressure (>1000 bar).
• Determine the required accuracy and resolution defined by the maximum measuring deviation in % of the measuring range.
• The applicable industry standards stipulate 0.1 % to 1 % deviation for precise applications.
• Are calibratable devices required for precise measurements?
• What type of pressure should be measured?
• Absolute pressure (refers to the vacuum as a reference).
• Relative pressure (refers to the ambient pressure).
• Differential pressure (measures pressure differences between two points, e.g. filter monitoring).
• Another point to consider is medium compatibility:
• Check the chemical resistance of the sensors and the materials used in the measuring device.
• What media does the measuring device come into contact with? Gases, water, oil, acids or abrasive substances?
• Are corrosion-resistant sensors, e.g. stainless steel, ceramics, required for measuring aggressive media?
• Determine the appropriate design and sensor technology for the measuring task:
• Mechanical pressure gauges are generally simple, robust devices which can often be used for on-site displays.
• Electronic measuring devices allow more precise measurements and make digital evaluation possible.
• Which electronic measuring principle is best suited to the intended task?
• Strain gauges → high precision, robust.
• Capacitive → very sensitive, for low pressures.
• Piezoelectric → ideal for dynamic pressure measurement.
• Resonance sensors → for maximum accuracy.
• The protection class and housing material should be adapted to the ambient conditions prevailing on site:
• IP protection classes: IP65 (dust and water jet protection), IP67 (waterproof), IP69K (high pressure cleaning).
• Housing materials: Stainless steel, plastic, aluminum or ceramic depending on the environment.
• Temperature range: Observe operating temperature, e.g. -40 °C to 85 °C.
• Also note the connection types when purchasing:
• Note thread types: G 1/4", G 1/2", NPT, M20x1.5.
• Flange connections for high-pressure applications.
• Quick couplings for flexible inserts.
• With electronic pressure gauges, it is important to pay attention to the measuring signal and the type of communication.
• Is the signal output analog or digital?
• Analog 4-20 mA, 0-10 V) → Standard in industrial systems.
• Digital I²C, RS485, CAN bus, HART, IO-Link → for networked applications.
• Is the measuring device compatible with the existing control system?
• Are there wireless options, e.g. Bluetooth or WLAN for Industry 4.0 applications?
• Is the device supplied with a factory calibration?
• Are ISO calibration protocols required?
• Is regular recalibration possible? At what intervals must these be carried out?
• Observe the applicable standards and certifications when purchasing: DIN EN 837 (mechanical pressure gauges), ATEX (explosion protection for hazardous environments), FDA/EHEDG (food & pharmaceutical standards), DVGW (drinking water approval).
• When purchasing, don't just pay attention to the purchase price. Cheap versions often have a shorter service life and require frequent replacement.
• Technical support and the availability of spare parts are particularly important for these components. Fast assistance in the event of a fault ensures operation.
• When purchasing, also note the warranty conditions specified by the manufacturer

When purchasing pressure gauges, in addition to technical specifications, long-term reliability, calibration, integration into existing systems and the supplier's service should also be taken into account. Careful selection saves costs and increases process reliability.

Pressure gauges can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Pressure gauges from all over the world can be found on Exportpages.