Advanced Specialty Gas Equipment

Models SG6520, SG6521
Pressure Gauges with Reed Switch

SG6520-3000 Gauge SwitchThese indicating pressure gauges with reed contact assemblies are designed to provide economical pressure monitoring, set-point indication and fast switching for low power electrical signals. In addition to providing accurate indication of gas pressure, these 21/2 inch diameter gauges incorporate a magnetically actuated reed switch capable of operating low voltage annunciators, lights or relays. They are commonly installed on regulators and manifolds to activate an external alarm (such as Models SG6551A, SG6552 Annunciators) when a certain predetermined pressure is reached.

The switch set point can be adjusted to any pressure between 2% and 90% of the full-scale value by moving the index on the front dial to the desired set point. On decreasing pressure only, the magnetic indicating pointer "opens" the switch when contact is made with the index. The gauge is designed to move further on the scale while permitting the switch to remain "open" after contact is made with the index.

Warning: We strongly recommend the use of our Explosion-Proof Type Pressure Switch Model SG6541 for all flammable and oxygen applications.

Dial Size: 21/2" diameter

Gauge Pressure Range

Adjustable Set-Point

Indication Accuracy: ± 2% of span

Operating Temp. Range: -20°F to 165°F

Case and Bayonet Ring: Type 304 Stn. Stl.

Window: Laminated safety glass retained in
   bayonet ring

Safety Feature: Solid front and full blow-out
   safety back

Dial: Aluminum alloy, white background,
   black markings

Bourdon Tube:
   SG6520: Bronze
   SG6521: Type 316 Stainless Steel

   SG6520: Brass
   SG6521: Type 316 Stainless Stee

Connection Size: 1/4" NPT male

Connection: 39" lead connection cable with 2 wires
Maximum Switching:
   Capacity: 10 watts (DC), 10 VA (AC)
   Current: 0.5 amps DC or AC with resistive load
Voltage: 75 Volts DC or 50 Volts AC
Dead Band: 2.5% maximum
Switch Operation: closes on increasing
pressure / opens on decreasing pressure
Model SG6520, SG6521

Table I
Part Number   Pressure Case Connection Adjustable Set-point
Brass Stainless Steel Range (psig) Configuration Location Min (psig) Max (psig)
SG6520-200-P SG6521-200-P 0–200 Panel Mount Lower Back 4 180
SG6520-600-P SG6521-600-P 0–600 Panel Mount Lower Back 12 540
SG6520-3000-P SG6521-3000-P 0–3000 Panel Mount Lower Back 60 2700
SG6520-3000 SG6521-3000 0–3000 Radial Bottom 60 2700