Pressure Measurement
Measurement, Monitoring and Leak Detection
Pressure readings show the working state of pump, filter and manifold. Supply pressure, return pressure and the differential across the strainer reveal whether the loop still carries its design flow, well before a temperature runs away. This category holds 3,621 items from Wika, Riegler, Cejn and Sang-A: bourdon tube gauges in vertical and horizontal versions with 40, 50, 63 and 100 mm dials, glycerine filled gauges with CrNi case, stainless chemical gauges and capsule gauges for low pressures from 25 mbar.
On the process side G 1/8, G 1/4 and G 1/2 are the usual threads, bottom entry or back entry for panel mounting. Spans run from -1 bar in the vacuum range through fine negative ranges such as -0.4 to 0 bar and -0.16 to 0 bar up to 250 bar. For a water-glycol loop the wetted parts belong in CrNi steel or 1.4571, brass only where the loop is of a single material family. Glycerine filling damps pulsation from the circulating pump and keeps the pointer readable.
Gauge designs compared
| Design | Dial size | Span | Material | Typical mounting |
|---|---|---|---|---|
| Bourdon gauge, bottom entry | 40, 50, 63, 100 mm | -1 to 250 bar | plastic or CrNi case, brass | in-line on pipework and manifolds |
| Bourdon gauge, back entry | 40, 50, 63 mm | -1 to 6 bar | plastic or CrNi case, brass | panel mounting |
| Glycerine filled gauge | 63, 100 mm | -1 to 250 bar | CrNi steel, brass | pulsating pressure close to the pump |
| Chemical gauge | 63, 100 mm | -1 to 4 bar and above | stainless steel, wetted | glycol mixtures, permanent media contact |
| Capsule gauge | 100 mm | 0 to 25 mbar | CrNi steel | low differential pressure, air and filter side |
- supply and return pressure on chiller, pump set and cooling manifold
- differential pressure across strainer and filter as a measure of fouling
- charge pressure on diaphragm expansion vessels and make-up units
- vacuum control during filling and venting of the glycol loop
- pressure testing of new pipe sections before commissioning
