differential pressure switch/ gages

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Differential Pressure

Switch/Gages

Differential Pressure Switch/Gages

•Photohelic

•Capsu-Photohelic

•3000MR/MRS

•Mini-Photohelic

Magnehelic Principle

The Photohelic and Capsu-Photohelic models combine our most precise

pressure switch with our time-proven Magnehelic design. The

knob controls adjust the set points. Two phototransistor actuated, DPDT

relays are included for low/high limit control.

Typical Applications To measure liquid level Use a Photohelic®, Magnehelic®, or Minihelic® gage in conjunction with a Dwyer flowmeter with constant differential pressure regulator as show. Flowmeter provides constant rate of purge air to dip tube. Changes in liquid level affect head, causing static pressure changes inside tube. These changes are sensed by the gage. This same kind of setup will also detect specific gravity changes in the liquid if level is kept constant. Using a Dwyer Photohelic® pressure switch/gage instead of the Magnehelic® permits both measuring and controlling liquid level plus easily changing the level control settings.

To control pressure in air-inflated buildings Photohelic® switch/gage senses over-pressure that may extend building, or loss of pressure that may cause collapse, and controls the blower to maintain correct pressure. Gage is easily reset to conserve power - or provide extra pressure to resist strong winds.

To control material weight On paper making or textile machinery, a Photohelic® switch/gage controls weight of material gathered by sensing pressure changes caused by changes in permeability and thickness of the material.

Typical Applications Monitor air conditioning systems Adjustments in air flow due to seasonal changes may require resetting the control points on a regular basis. The Photohelic® unit's ability to monitor pressures through the gage portion also permits accumulation of operating data. This is useful in adjusting operation of variable pressure and volume systems and in making system changes when necessary.

For life support or kidney machines Photohelic® switch/gage controls pressure on circulating system of machine and alarms in event of too high or low pressure.

Specifications Series A3000/3000

Photohelic Differential Pressure Switch/Gages

• Media: Air and non-combustible, compatible gases

• Pressure Limits: -20” Hg to 25 psig

• Temperature Limits: 20o to 120o F

• Connections: 1/8” female NPT

• Accuracy: +/- 2% full scale (3% on -0, 4% on -00 ranges)

• Wetted Parts: Aluminum housing with silicone diaphragm

• Power Supply: 120 VAC

• Special Note: For non UL/CSA listed Photohelic models delete the “A” prefix from the model number.

Design & Construction Features

1. Bezel and front cover (with set point knobs and zero adjustment screw) removed to expose Photohelic set point mechanism. Cover is clear polycarbonate plastic. 1

2 2. Gage pointer and light shutter are mounted on helix and balancing counterweight. Shutter passes through slot in optical limit switch to expose phototransistors to integral infrared light source or mask them depending on applied pressure

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3. Light shield effectively protects phototransistors from strong outside light sources yet allows free pointer movement. It also gives interior a clean "finished" look.

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4. Semi-Flexible drive shaft connects to set point knobs.

5 5. Optical limit switches are used for reliability and long service life. Attached directly to set pointers, they are individually aligned to assure precise switching accuracy.

6 6. Zero adjustment screw connects to screw in cover to adjust zero pressure reading.

Design & Construction Features

7. Plastic enclosure protects electronic components and electrical connections.

8. Polycarbonate connection or terminal board is self-extinguishing(A3000 only). 9. Glass epoxy printed circuit boards for durability and permanence.

10. Load relays are DPDT with latching feature for maximum application versatility.

11. Electronics are designed to operate on 50/60 Hz, 120 volt current with 10% over or under voltage. Special units for other voltages are available.

12. Switch set pointers show switch settings at all times.

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13. Spring loaded friction clutch prevents operator damage of set point mechanism.

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Options

• -24VAC: 24 VAC Relay Pack

• -240VAC: 220/240 Relay Pack

• -EXPL: Explosion Proof Housing

• -G: Green Overlay

• -HC: Horizontal Calibration

• -HJ: Helix Jump Preventer

• -HP: High Pressure (80 psi)

• -OLS: Less Relay

• -LT: Low Temperature

• -M: Mirror Overlay

• -MP: Medium Pressure (35 psi)

• -NIST: NIST Certificate

• -RMR: Remote Mounted Relay (5ft)

• -SRH: Single Right Hi Latching

• -SRL: Single Right Lo Latching

• -R: Red Overlay

• -TAMP: Tamperproof Knobs

• -WP: Weather Proof Housing

Accessories: A-601, manual reset switch

Special Scales

Like the Magnehelic, Dwyer also offers special scales on the

Photohelic. Any equivalent range within the gage’s capabilities can be made. These scales include ranges in Pa, KPa, mm WC, and inches Hg or flow ranges in FPM, CFM, GPM,

CFH, M3H, and PPH.

Specifications Series 43000

Capsu-Photohelic Differential Pressure Switch/Gages

• Media: Compatible gases and liquids




• Accuracy: +/- 3% full scale (2% on 43000S models, 4% on

43215, 43220, 43500)

• Wetted Parts: Aluminum housing with silicone diaphragm, optional brass housing

• Power Supply: 120 VAC

Options


• -240VAC: 220/240 Relay Pack




• -OLS: Less Relay




• -RMR: Remote Mounted Relay (5ft)

• -SRH: Single Right Hi Latching

• -SRL: Single Right Lo Latching

• -R: Red Overlay



Special Scales

Dwyer also offers special scales on the Capsu-Photohelic. Any

equivalent range within the gage’s capabilities can be made. These scales include ranges in Pa, KPa, mm WC, and inches Hg or flow ranges in FPM, CFM, GPM, CFH,

M3H, and PPH.

Specifications Series 3000MR/MRS

Photohelic Differential Pressure Switch/Gages





• Accuracy: +/- 2% full scale (3% on -0, 4% on -00 ranges)

• Wetted Parts: Aluminum housing with silicone diaphragm

• Power Supply: 24 VDC

Differences from standard model

Only 2 SPDT contacts on MR model. The MRS has SPST solid state outputs.

3000MR/MRS has cable for wiring instead of screw terminal relay pack.

Options





• -HJ: Helix Jump Preventer

• -HP: High Pressure (80 psi)


• -MP: Medium Pressure (35 psi)



• --R: Red Overlay



Specifications Series MP

Mini-Photohelic Differential Pressure Switch/Gages


• Pressure Limits: 30 psig


• Connections: Barbed for 3/16” tubing

• Accuracy: +/- 5% full scale

• Wetted Parts: Nylon housing with silicone diaphragm

• Power Supply: 24 VDC or 24 VAC

Questions

To order a free catalog or for more information contact;

Dwyer Instruments, Inc., P.O. Box 373, Michigan City, IN., 46361

Telephone: (800) 872-9141 or (219) 879-8000 Fax: (219) 872-9057

Internet address: www.dwyer-inst.com E-mail: [email protected]

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