Make the right decision for your differential pressure application.

PISTON TYPE

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DIAPHRAGM TYPE

piston gauges   diaphragm gauges

Piston Type Differential Pressure Gauges

Mid-West Piston Type: ± 2% or ± 5% Full Scale Accuracy.

They are primarily designed for liquid applications. They exhibit a slight amount of bypass as the fluid crosses from the high to the low pressure port. Because gas molecules are smaller, the crossover is often deemed too great for the application. The Differential Pressure is sensed by the movement of a precisely ground floating piston/magnet in a precision bore against a calibrated spring. Any variation in pressure on either side of the piston/magnet will cause the magnet to move proportionally to the change in differential pressure. A rotary pointer magnet located close to the internal magnet, but outside the pressure housing, follows the movement of the piston magnet and indicates differential pressure on the dial. Note: Due to precision sizing of piston and body bore, leakage across the piston will not exceed 15 SCFH air at 100 P.S.I.D. at ambient conditions.

Piston-Type gauges are available with one or two hermetically sealed reed switches or 4-20mA transmitter depending on model. The switches are adjustable within a defined percentage of the full scale range of the gauge and are available in SPDT and SPST, normally open or normally closed configurations for various load power ratings. The switches can be set to activate or deactivate on rising or falling pressure. The standard reed switch is enclosed in a weather-resistant plastic housing. Adjustment of the switch setting is made with an external screw adjustment.

All Hazardous Location switches are CSA & UL Listed. The CSA & UL listings are for the entire design and not just the enclosure. Standard and weatherproof units are CE marked for conformance with the Low Voltage Directive to harmonized standard EN 61010-1.

Contact Mid-West @ 1-800-648-5778 for more information.

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Diaphragm Type Differential Pressure Gauges

Mid-West Diaphragm Type: Models 140 & 142 ± 2% Full Scale Accuracy.

The high and low-pressure ports are completely isolated from each other. There is no bypass and therefore they are best suited for air or gas along with liquids. They also come in a variety of sizes allowing for very sensitive measurements. The Differential Pressure is sensed by the movement of an elastomer diaphragm against a precision calibrated range spring. The change in position of the diaphragm in response to the change in Differential Pressure moves an internal magnet. This magnet, in turn, causes a rotary magnet external to the gauge body to rotate. This rotary magnet has a pointer attached which indicates the differential pressure on the dial. The diaphragm provides total separation.

Diaphragm-Type are also available with either one or two hermetically sealed reed switches for either high alarm, low alarm, or both and a 4-20mA transmitter depending on model. The switches are Single Pole Double Throw (SPDT) or Single Pole Single Throw (SPST) with adjustable set points. Switches can be set to activate/deactivate on rising or falling pressure. Standard switch enclosure is non-corrosive molded plastic that is oil tight, dust tight, and water tight per NEMA 4X. External access to the switch adjustment is provided. CSA Listed Explosion Proof enclosures with SPDT or SPST switches rated Class I, Groups C & D, Class II, Groups E, F, & G are available. Switch leads are 24", 18 Awg, and are color coded where applicable.

Contact Mid-West @ 1-800-648-5778 for more information.

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