Hydraulic pressure gauge function
The most common operating principle used in hydraulic pressure gauges is the Bourdon tube. This technology dates back to the mid-nineteenth century. This is a simple way to show hydraulic pressure in a high precision system. This pipe is usually created by smoothing a circular cross-section pipe and creating a C or helix. One end of the “C” is fixed to a block and connected to an inlet pipe for the pressurized liquid, while the other end is closed and free.
The figure above shows the main components of a Bourdon tube. Pressurized hydraulic fluid enters the measuring device in the inlet pipe (A). The inlet pipe is held by a socket block (B), which also holds the machine to the process line. Fluid pressure flows to the fixed end of the Bourdon tube (C). The pressure is transmitted through Figure C to the movable end of the Bourdon tube (D). This pressure forces the C-shape to flatten. At the movable end of the Bourdon tube, an axial and axial base (E) connects the right-hand drive to the gear (F). The gear system amplifies the motion at the movable end of the Bourdon tube so that very little pressure change results in significant motion of the marker needle (G). As a result, the marker moves in a circular path, usually from left to right, on a calibrated scale.
The scale can be from 0 to 1000 bar (14503.77 PSI) or more for hydraulic pressure gauge. Large scale is usually the most obvious difference between hydraulic pressure gauges and other pressure gauges, such as weather. The components of the hydraulic pressure gauge are designed for a specific measuring range and have a special accuracy that is indicated by the calibrated step scales of the pressure scale.
When measuring pulse pressure, such as when a hydraulic pressure gauge is placed near a reciprocating pump, a constraint is placed inside the inlet pipe just before the fixed end of the bourbon tube to prevent unnecessary wear of the gears. It is also common for hydraulic pressure gauges to be installed on equipment that cause mechanical vibrations throughout the gauge. Therefore, the whole case, including the marker, is filled with oil or glycerin to reduce the vibrations of the marker.
Another type of hydraulic pressure gauge is the following gauge. Its principle of operation is quite similar to that of a Bourdon tube, except that it uses a spring attached to a plate to calculate the intensity of the liquid. As the fluid pressure changes, the spring expands and compresses, and the force generated is transmitted to the gears that move the pressure plate.
Standards for hydraulic pressure gauges
The European Standards Committee (CEN) has the following standards for defining barometers: terms, specifications, requirements and more:
EN 472: Vocabulary of pressure gauge.
EN 837-1: Bourdon tube pressure gauge. Dimensions, measurements, requirements and tests.
EN 837-2: Selection and installation recommendations for pressure gauges.
EN 837-3: Diaphragm and capsule pressure gauge. Dimensions, measurements, requirements and tests.
Criteria for selecting hydraulic pressure gauges
- Measuring range : The measuring range of hydraulic pressure gauge is much larger than the weather due to its application. Conventional hydraulic equipment has the maximum allowable pressure characteristics. If the range of hydraulic pressure measurement is much larger than the operating range of hydraulic equipment, there is a possibility of unnecessary gauge accuracy. Always choose the narrowest measuring range for higher accuracy.
- Size and type of connection : There are hydraulic pressure gauges in different sizes of connection. Make sure you choose a much smaller space in your hydraulic system that fits your retaining socket. It is the most common type of gear connection.
- Connecting materials : Hydraulic pressure gauges have different connecting materials such as brass, copper alloy, etc. Make sure the materials selected are compatible with your process and the socket. Brass is used for non-corrosive fluids, stainless steel is durable, while plastic is inexpensive and has corrosion resistance. Before deciding, please check our material flexibility chart.
- Joints : Possible junctions can be confused below, up or back. Consider the space available in your system and its impact on the connection location.
- Vibrations, pulses and pressure increases : Unlike other pressure gauges, hydraulic pressure gauges are often selected based on the vibration management capacity of the process equipment. Check that the pressure gauge has a mechanism such as a filler fluid to manage such operating conditions in hydraulic systems. Some of the things to consider are the viscosity and type of filler (water, oil or glycerin), the operating temperature of the liquid, the effect on the response time and the frequency of the expected vibrations. Glycerin is commonly used to protect against vibration at room temperature. Silicone oil is common for applications of temperature fluctuations at high and extreme temperatures. If the system is exposed to electrical contact, consider the type of oil selected. In this case, use insulating oil.
- Maximum operating temperature : Most hydraulic pressure grilles operate in the maximum temperature range of 60 to 80 degrees Celsius. There is a special hydraulic pressure gauge for high temperature applications.
- Unit of measure : For measuring pressure gauge, it has both bar and psi scales.
- IP protection : IP code is important, especially if you use a hydraulic pressure gauge in a dusty, condensing or sprinkler environment. Higher IP ratings will also mean higher confusing costs.
- Digital reading : There is an option to digitally display the measured hydraulic pressure. Hydraulic pressure gauges with digital displays can often transfer the amount of reading to a remote control. If this meets your needs, consider and remember that it needs power. However, most hydraulic sphygmomanometers have a dial indicator and do not require external power to operate.
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