FW Murphy Pressure & Vacuum Gages

Murphy's heavy-duty mechanical Swichgage® and Murphygage® pressure and vacuum instruments feature rugged industrial-rated diaphragm movement, a tough PVC-armored capillary, plated steel case, polycarbonate lens and a stainless steel bezel. The gages are available in 2, 2.5 and 4.5 inches (51, 64, and 114 mm). The 4.5-inch version features a bourdon tube sensing element, plus adjustable high and low limit contacts or snap-acting switches. Murphy's “A-series” products include environmental sealing to keep out damaging condensation.

 

20V, 25V, A20V and A25V Series Vacuum Swichgage®

murphy.20VThe 20 Series (2 inch/51 mm dial) and the 25 Series (2-1/2 inch/64 mm dial) Swichgage instruments are diaphragm-actuated, vacuum- indicating gages, with built-in electrical switches. These switches are used for tripping alarms and/or shutdown devices.

The 20 and 25 Series gage mechanism is enclosed in a steel case coated to resist corrosion.

The A20 and A25 Series gage has a polycarbonate case and is sealed from the environment. All gages feature a polycarbonate, break-resistant lens and a polished, stainless steel bezel to help protect these rugged, built-to-last instruments.

The gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have a self-cleaning motion to ensure electrical continuity.

Gage-only models, without contacts (Murphygage® instruments), are also available.

A pulsation dampener (PD2160) is included with each Swichgage to help eliminate pointer flutter. When monitoring intake manifold vacuum, the PD2160 is mounted in the manifold. The PD2160 has a 1/8-27 NPT connection. A vacuum tubing kit (V5179) is available for all models to help reduce pulsations. The kit includes 48 inches (1.2 m) of copper tubing and two compression fittings. Specify tubing kit V5179.

Applications
Commonly used to measure loading of spark ignition engines through intake manifold vacuum.  Also can serve as overspeed protection from sudden loss of load on these engines.  Use anywhere the vacuum source is compatible with port materials.
Literature
• Sales Bulletin (pdf)
• Installation Instructions (pdf)

20VWC, 25VWC and A25VWC Series Air Filter Restriction Swichgage®

murphy.20VWCThe VWC Series Swichgage instruments are direct reading gages for use with dry air filters. As the filter deteriorates, air inflow will decrease cre- ating increased vacuum between the air filter and the carburetor. The vacuum is monitored by the Swichgage instrument which gives a visual read- out of the filter condition. A built-in adjustable limit contact can operate an alarm to alert the operator when it is time to service or replace the air filter element. Murphygage indicating-only instruments are also available.

20VWC and 25VWC models feature a steel case and are available with dial illumination. The A25VWC model has a glass filled polycarbonate case. Standard models have a range of 0 to 30 in. (0-76 cm) of water restriction. Optional 0-50 in. (0-1.27 m) range is available. Please consult your engine operators manual for the recommended restriction limit for dry air filter servicing.

Applications

VWC Series Swichgage instruments can be used on any type of dry air filters for gasoline or diesel engines. They are particularly useful for engines operated in dusty environments such as agricultural and construction equipment, industrial engines and mobile equipment. Unlike traditional pop-up or latch-up type indicators, the VWC Series gives constant readout in meaningful terms of the changing condition of your filter.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)

20P and 25P Series Pressure Swichgage®

murphy.20PThe 20 Series (2 inch/51 mm dial) and the 25 Series (2-1/2 inch/64 mm dial) Swichgage® models are diaphragm-actuated, pressure-indicating gages, with built-in electrical switches. These switches are used for tripping alarms and/or shutdown devices. Ranges are available from 0-15 psi (103 kPa) [1.0bar] thru 0-400 psi (2.8 MPa) [28 bar].

The gage mechanism is enclosed in a steel case coated to resist corrosion. A polycarbonate, break-resistant lens and a polished, stainless steel bezel help protect this rugged, built-to-last instrument. Accuracy and protection from moderate overpressure is assured by a unique, unitized diaphragm chamber. A built-in pulsation dampener helps eliminate pointer flutter and is removable for cleaning.

For models 20P and 25P, the gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts are grounded through the Swichgage case and have self-cleaning motion to ensure electrical continuity.

Models 20PE and 25PE have internal snap-acting SPDT switches.

Gage-only models, without the switches (Murphygage® instruments) are also available.

Applications

The Swichgage® was specifically designed to protect engines/equipment in Oil Field, Marine, Irrigation, Construction and Trucking applications to monitor Engine Lube Pressure, Water Pump Pressure, Hydraulic Pressure, Air Pressure, etc.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)
• Installation Instructions - Transmission/Gear Pressure models (pdf)

A20P and A25P Series Pressure Swichgage®

murphy.A20PThe A20 Series (2 inch/51 mm dial) and the A25 Series (2-1/2 inch/64 mm dial) Swichgage instruments are diaphragm-actuated, pressure-indicating gages, with built-in electrical switches for tripping alarms and/or shutdown devices.

Ranges are available from 0-15 psi (103 kPa) [1.0 bar] thru 0-400 psi (2.8 MPa) [28 bar].

All models of these rugged, built-to-last instruments are face sealed from the environment by the unique combination of a polycarbonate case and lens, a polished stainless steel bezel and O-ring seals. Ranges above 30 psi (207 kPa) [2 bar] are totally sealed from the external environment (except PE Series).

Accuracy and protection from moderate overpressure is assured by a unique, unitized diaphragm chamber. A built-in pulsation dampener helps eliminate pointer flutter and is removable for cleaning.

For series A20P and A25P, the gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have self-cleaning motion to ensure electrical continuity.

Models A20PE and A25PE have internal snap-acting SPDT switches for three wire control; can be wired to make or to break a circuit.

Gage-only models, without switches (Murphygage® instruments) are also available.

Applications

A20/A25 Series applications include: engines/equipment in Oil Field, Marine, Irrigation, Construction and Trucking Engines for Lube Oil Pressure, Water Pump Pressure, Hydraulic Pressure, Air Pressure, etc.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)

20DP, 25DP, A20DP and A25DP Series Differential Pressure for Filter Restriction

murphy.20DPThe 20DP and A20DP Series (2 inch/51 mm dial) and the 25DP and A25DP Series (2-1/2 inch/64 mm dial) Swichgage instruments are diaphragm-actuated, differential pressure-indicating gages, with a built-in electrical switch. This switch is used for tripping alarms and/or shutting down equipment. These gages are intended to monitor and indicate oil, fuel or water filter restriction and can reduce the risk of dangerously high pressure which may rupture the filter, resulting in contaminants entering the system. 

The 20DP and 25DP series mechanism is enclosed in a steel case coated to resist corrosion. The A20DP and A25DP series have a polycarbonate case and are sealed from the environment. All gages feature a polycarbonate, break-resistant lens and a polished, stainless steel bezel to help protect these rugged, built-to-last instruments.

The gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have a self-cleaning motion to ensure electrical continuity.



Features

Constant Visual Indication of the condition of your filter is shown on the dial.

Two Instruments In One – an accurate indicating gage and adjustable p.s.i.d. limit switch. Reduces inventory and installation time.

Adjustable Contact lets you set the monitoring range of the gage. The contact is tamperproof and can be set with a common 1/16" Allen-head wrench.

Durability – All gages are made of durable materials allowing them to withstand rugged applications.

Early Filter Changes cost you money and increase the risk of contaminants entering the system. A Murphy filter restriction Swichgage instrument will let you know when to change the filter and maintain peak efficiency.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)

B-Series Murphygage® Pressure, Vacuum and Temperature Instruments

murphy.20BPGThe B-Series Murphygage® instrument is a high quality, diaphragm-actuated indicating gage. Built by Murphy with the same heavy-duty design as the standard 20 series and 25 series Swichgage® instrument, the B-gage is more compact and is the optimum instrument for gage-only applications. It has a high impact polycarbonate lens, sturdy steel case, and a polished, low-profile stainless steel bezel. Accuracy and protection from moderate over-pressure/over-temperature are assured by a unique, unitized diaphragm chamber, superior quality materials, and the design of the gage movement.

Pressure Murphygage® Instrument
Pressure changes at the diaphragm convert to accurate mechanical movements that are indicated on an easy to read analog dial. A pulsation dampener in the pressure port helps eliminate pointer flutter; it can be removed for cleaning to maintain the gage’s response and accuracy.

Vacuum Murphygage® Instrument
Available in 0 to 20 or 0 to 30 in. Hg. (0 to -68 or 0 to - 102 kPa) vacuum.

Temperature Murphygage® Instrument
As temperature rises, the fluid in the sensing bulb vaporizes to apply pressure on the diaphragm; the movement translates this vapor pressure to a calibrated reading of temperature on the dial. The standard capillary is copper with a PVC armor. Optional armor covering is galvanized steel or 316 stainless steel (specify). Optional bulb types, adaptor nuts and thermowells are available. For optional temperature capillary lengths, engine adaptors, sensing bulbs and range combinations, see Murphy Bulletin T-8428B.

Applications

Industrial engines and equipment in Oil Field, Marine, Irrigation, Construction and Trucking industries. Monitoring Engine Coolant, Crankcase Oil and Transmission Oil.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)

Direct Mount Pressure Switch: Model PSB

murphy.PSBThe PSB switch is a direct mount switch for critical pressure points. It has one limit contact that can be used to activate an alarm, actuate indicator lights or shutdown equipment.

The construction of this instrument is the same as our time-proven Swichgage® instrument. A precision machined brass mounting plate and port captures a high quality stamped beryllium copper diaphragm. The single-pole, double-throw (SPDT) snap-switch is operated directly from the diaphragm for quick acting and positive switching. Trip point is factory preset according to your specifications.

Housing is weather sealed to prevent entry of moisture, dust, etc. A glass-filled nylon terminal block with quick screw terminal connections gives the PSB switch a real advantage in industrial engine applications. The PSB is ideal when reading is not desired, but pressure is critical to operational efficiency. Intended for use in general purpose nonclassified areas.

Features

• Fits all engine applications
• SPDT snap-switch
• Activates indicator lights, alarms, or shut down equipment
• Time-proven Swichgage construction
• Easy wiring terminal block
• Steel housing specially coated to resist corrosion
• Factory preset to your specifications

Applications

• Engine lubrication
• Water pumps
• Compressors
• Oil field systems
• Irrigation systems
• Construction equipment
• Light-duty mobile equipment
• Marine engines
• Generators features
• Fits all engine applications
• SPDT snap-switch
• Activates indicator lights, alarms, or shut down equipment
• Time-proven Swichgage construction
• Easy wiring terminal block
• Steel housing specially coated to resist corrosion
• Factory preset to your specifications

Literature

• Sales Bulletin / Installation Instructions (pdf)

OPL Series Pressure Gage and Swichgage® Instruments

murphy.OPLCThe OPL-Series Pressure Swichgage instruments are combination pressure indicating gages with adjustable low and high limit switches. Limit switches can be wired directly to electric pilot circuits to operate alarms, shutdown or start/stop of engines and electric motors.

Surface mount or panel mount enclosure is available for most versions. All versions feature a 4-1/2 in. (114 mm) dial for easy viewing. Adjustable limit switches are accessible from front of the Swichgage instrument. Limit contacts have self-cleaning motion to enhance electrical continuity.



Other versions available:
• Gage-only without contacts (Murphygage® instruments)
• Swichgage instrument with built-in latching relay for start-stop operations.

Base Models

OPLC, OPLCE and OPLG
The OPLC is a surface mount, indicating, pressure gage and switch. Adjustable high and low limit, ungrounded contacts are used to operate alarm, shutdown or start-stop circuits. Pointer closure against either of the adjustable contacts completes the pilot-duty circuit.

An SPST toggle switch is provided to override the low limit contact for equipment startup. Suitable for engines or electric motors with appropriate Murphy magnetic switch or trans- former relay assembly.

The OPLCE features a panel mount square case. It has all the features of the OPLC except the low limit contact lockout.

The OPLG is an indicating-only pressure Murphygage instrument. Same as the OPLC except without switch (limit) contacts.

OPLFC and OPLFG
The OPLFC is a panel mounting version of the OPLC. It has all of the features of the OPLC except the low limit contact lockout. The lockout must be done externally through the con- trol circuit or with the optional “SA” lockout. The OPLFC is typically used in control pan- els such as for compressors, pumps, etc. This version can be environmentally sealed with either the “ES” or “OS” options. Contact lead termination is by pigtail wires.

The OPLFG is an indicating-only pressure Murphygage instrument. Same as the OPLFC except without switch (limit) contacts.
 
OPLBP and OPLBPE
The OPLBP is a specialized version of the OPL series designed for start-stop operation of engines and electric motors. The pilot-duty limit switches are connected to an internal latching control relay for ON/OFF automation. Available for various voltages.

The OPLBPE is the same as the OPLBP except has a panel mount square case.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)

PXT Series Pressure Transmitters

murphy.PXTPXT Series pressure transmitters are state-of-the-art instruments providing 4 to 20 mA outputs. They feature a precision micro-machined silicon diaphragm with a fully welded stainless steel pressure port for greater accuracy, stability and a wide range of compatibility.

Silicon technology is used to provide a miniature micro-machined diaphragm which is electrostatically bonded to a glass substrate and is then stitch-bonded within a glass to metal seal assembly to provide exceptional thermal and stress isolation. This technology assures you of high accuracy and stability over a wide range of operating conditions.

The enclosure is made of 316 stainless steel  and all wetted parts are 316L stainless steel or HASTELLOY C276.

Applications

The PXT can be used in applications such as Compressors, Engines, Process Control, Liquid Level and Pumps.

Literature

• Sales Bulletin (pdf)
• Installation Instructions (pdf)
• Installation Diagram (pdf)



 
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