There is much hydrostatic pressure gauge in the market, but the basic construction and therefore the working is almost similar. Given below is the complete description of how it is constructed, that is, its different parts and its working principle.
External and Internal Construction of Pressure Gauges
All pressure gauges are made of stainless steel and filled with glycerin. The purpose of glycerin is to lubricate and keep the needle from vibrating. It has a front ring with a lens on it. On the back side of the pressure gauge are the two screws on the protective cover.
The internal skeleton is entirely made from brass except for a copper tube, the Bourdon tube. It is nothing more than a bent tube in a circular formation. It is then attached to the square brass part at both ends. This means that it is airtight.
The front face has the calibrations and the needle. It usually measures up to 100psi, where psi stands for ‘pounds per square inches.’ Some pressure gauges also tell the pressure in Kilopascal unit. There is a little pin for the zero calibration that stops it going any further than that point.
How does it work?
As the air pressure is turned on the needles also move. As the pressure is turned off, the needle also comes back to zero
When the pressure comes in, the bourdon tube attempts to straighten out. In some way, you can think of it as a party whistle, that means that it attempts to straighten out and then comes back to its original position.
There is a small link fasten on the bourdon tube with the help of screws, and that is also linked to the movement. The motion is transmitted through the linkages which in turn move the needle. The shaft that goes to the needle, there is a tiny gear, the opinion.
There is another gear that is also attached to this opinion. This year, due to pressure, is linked to the shaft and makes it move, which in return result in the movement of the needle. There are many linkages, one of them is used to calibrate the needle as the pressure makes it move.
The use of pressure gauges varies among its different types. Mostly they are used to measure the temperature by comparing it with the atmospheric pressure. The zero reading is taken equal to the atmospheric pressure, and the measurements are made according to this standard. Many gauges are very accurate for measuring even very small pressures.
If you want to buy hydrostatic pressure gauge, they are not expensive at all; rather they are available at very low prices. Also, those that are of laboratory grade are very accurate in their measurements. On average, the pressure gauges are not at all critical to handle and use.
Keeping in mind the above-detailed description of how a hydrostatic pressure gauge works can be beneficial if you are planning to work on the instrument.