The piston sensor differential pressure gauge is the most popular and economical model used mostly to monitor filtration contamination level. The gauge and/or switch will prevent flow starvation and cartridge collapse in fluid filtration systems. The sliding seal is similar to a hypodermic needle seal, and will allow microscopic media migration from the high to low sections.
200 DPG - Piston Instrument
EX-200 DPG - Explosion Proof Piston Instrument **
Low-cost option:
Series DX 10 - Piston Instrument

Rolling Diaphragm Differential Pressure Gauge

The rolling diaphragm differential pressure gauge is used when media migration of any amount is unacceptable. While filtration is common for this gauge, it can be used in heat exchangers or other dissimilar liquid systems where a positive pressure must be maintained for safety. Usage in systems which will see pressure reversals is not recommended.
200 DGR - Rolling Diaphragm
EX-200 DGR - Explosion Proof Rolling Diaphragm **

Small Convoluted Diaphragm Differential Pressure Gauge

The small convoluted diaphragm differential pressure gauge is recommended for the lower ranges of differential pressure as the area of pressure impingement is larger, and capable of sensing lower differential pressures. This differential pressure gauge is widely used for liquid level display. Also it is used to display flowrate through an orifice or venturi (nozzle) as the liquid flow is proportional to the square root of the pressure differential, and can easily be provided with special dials called square root dials.
300 DGC - Small Convoluted Diaphragm
EX-300 DGC - Explosion Proof Small Convoluted Diaphragm **

Medium Convoluted Diaphragm Differential Pressure Gauge

The medium convoluted diaphragm differential pressure gauge is used where very low differential is required and the larger diaphragm is able to display differential pressures as low as 0-2 inches H2O.
400 DGC - Medium Convoluted Diaphragm
Low-cost option:
Magnetic 600 Medium Convoluted Diaphragm

**Explosion Proof Options
Explosion proof option is available for use in hazardous combustible environments where an electrical signal is used and the contact is completely contained within the agency-approved box.