PRESSURE GAUGE APPLICATION Pressure is one of important parameters in industry production, to protect system work well, it is important to monitor the pressure used in the system. Because the power always come from pressure. So pressure gauge used in the industry very widely, such as hydraulic system, compressors and compressed air system, oil industry, electricity power industry, food production industry and so on.
HOW TO SELECT A PRESSURE GAUGE
Selecting a pressure gauge: the subjects listed below can be used as a guide to ensure to ensure that proper consideration is given to all factors affecting the choice of a pressure gauge.
(caution: operating conditions including, but not limited to, system pressure,media compatibility and ambient conditions must be considered when selecting gauges could cause gauge failure and lead to possible property damage and personal injury.)
1) PRESSURE RANGE: Select a range so that the expected operating pressure falls in the middle half of the
gauge (25% to 70% of full scale), if short duration pressure pulses are expected , the range may need to be
increased to avoid damae to some types of guage . normally range from 0 psi to 10000psi and vacuum can be
tested with bourdon tube .so can select bourdon tube gauge , but micro pressure, (for example 160mbar) should
be tested with capsule . so have to select Capsule gauge.
PRESSURE UNIT CONVERSATION
|
Pa |
kgf/cm2 |
cmHg |
mmHg |
mmH2O |
torr |
atm |
psi |
bar |
1Pa |
1 |
1¡Á10-5 |
7.5¡Á10-4 |
7.5¡Á10-3 |
0.10204 |
7.5¡Á10-3 |
9.869¡Á10-6 |
1.4¡Á10-4 |
0.00001 |
1kgf/cm2 |
98067 |
1 |
73.556 |
735.66 |
10007 |
735.56 |
0.96783 |
14.22306 |
0.98066 |
1cmHg |
1333.22 |
0.01359 |
1 |
10.00 |
135.6 |
10.00 |
0.0131 |
0.1933 |
0.0133 |
1mmHg |
133.322 |
0.00136 |
0.100 |
1 |
13.56 |
1.000 |
0.00131 |
0.01933 |
0.00133 |
1mmH2O |
9.8067 |
0.00010 |
0.007355 |
0.073556 |
1 |
0.073556 |
0.00009 |
0.00142 |
0.00009 |
1torr |
133.322 |
0.00135 |
0.1 |
1 |
13.6 |
1 |
0.00131 |
0.01933 |
0.00133 |
1atm |
101325 |
1.03323 |
76 |
760 |
103.40 |
760 |
1 |
14.6959 |
1.01325 |
1psi |
6894.7 |
0.0703 |
5.1714 |
51.714 |
703.597 |
51.714 |
0.06804 |
1 |
0.06894 |
1bar |
100000 |
1.01972 |
75.006 |
750.006 |
10204 |
750.06 |
0.98692 |
14.50372 |
1 |
2) Operate Condition: Normal condition in house, and no vibration and pulsation, we can select dry gauge, but
if there are vibration and pulsation in the system, we should choose liquid filled gauge protect the normal indic-
-ating pressure in the gauge. And if the system need to control with the pressure. We can choose electrical contact
gauge or pressure switch or pressure transmite to replace the normal gauge. If you are considering a gauge which
will be an operator, a process gauge with a soild front construction will provide an extra measure of safety, if you
require in -house calibration, specify a micrometer adjustable pointer and bayonet ring case, while a large case
will be easier to read, case size consideration are generally driven by available space, connecting considerations
and accuracy requirement.
3) Environmental consideration: if the gauge will be used in normal condition, such as normal air, the case can
be made of steel powder coated black or chrome plated, or plastic, but if the environment is severe or corrseive, a
stainless steel case may be indicated.
Ambient temperature, humidity, vibration, corrosive gasses, and weather must all be considered when selecting a
pressure gauge, the environmental temperature limits for most shunjay pressure gauges are shown in the table
beloe. Generally all shunjay pressure gauge are dust proof, and filled gauge or fillable gauge are water proof.
ENVIRONMENTAL LIMITES |
DAMPING FLUID |
RECOMMENDED TEMPERATURE RANGE |
Dry |
-13 to 150¡ã F |
-25 to 65¡ãC |
Glycerine |
60 to 150¡ã F |
-15 to 65¡ãC |
Silicon |
-50 to 150¡ã F |
-45 to 65¡ãC |
Working Fliud: normal fluid such as air , water ,and inert gas can use copper alloy as the wetted parts , but If the working fluid is corrosive , stainless steel wetted parts should be considered ,and acytelen need to use brass wetted parts. And oxygen need wetted part oil prohibiting . we can use diaphragm sealed pressure gauge to measure the corrosive fluids pressure , where suitable material for bouden tube is not avalible . also diaphragm sealed gauges can be used for systems needing contact surface that ar, e&nbs, p, ;rigorously cleaned and totally safe, the function of the diaphragm is to isolate the pressure gauge from the process fluid , preventing bacteria developing inside pressure gauges sensing element.and easy to clean and quick release coupling.
Mounting: as a rule , all gauges are available in stem mount, lower connected and stem mount , back connected, not all gauges re available in all mouting configuration for a sketch of mouting types see the mounting codes examplesillustration as below table, if your application involves excessive vibration or requires a large gauge, consider specifying a gauges which is mounted buy some method other than the stem , for example , U-clamp or surface mount gauge , this will reduce the stress on the stem and promote more reliable operation.
Connection : Shunjay pressure gauges are availbe in a wide variety of connection , BSP threads are the standard configurtion, if you have a requirement for a connection not listed , contact with Shunjay.
options: BSP, BSPT, NPT, Metric thread, hose connection
Accuracy :Select a gauge with sufficient accuracy to satisfy your requirments , special precis appliation need to choose precise pressure gauge.
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