Type 75 - T75 HR Precision Relay - Fixed Negative Bias Relay (4psi)
The Bellofram Precision Controls Type 75HR Fixed Negative Bias Relay combines pneumatic signal control, high-relief exhaust, and an internal 4 ± 1 psig negative-bias function. The relay automatically reduces the incoming signal by approximately 4 psi while using a balanced valve and aspirator system to maintain stable output over changing flow and supply conditions. At the stated test condition, forward flow is about 41 SCFM and exhaust capacity is about 16 SCFM. This configuration is suited to electronic-to-pneumatic control interfaces, volume boosting, tensioning, clutch and brake control, cylinder return strokes, air hoists, and other applications requiring both negative bias and fast exhaust.
Features:
- Balanced Valve Design
- High Flow Capacity
- Field Serviceable
- Multiple Output Ratios
- Negative Biasing Option
- Can Be Disassembled and Serviced Without Removing from Line
- Gas Flow Control
- Tensioning Control
- Clutch and Brake Controls
- Volume Boosting
- Dancer Roll Loading
- Calendar Roll Loading
- Cylinder Bucking Control
- Valve Motor Loading
- Cylinder Return Stroke Actuation (75HR)
- Air Hoists (75HR)
- Electronic Control Applications (Negative Biasing Version)
Maximum Supply Pressure
250 psig (17.2 BAR)
Pressure Ranges
0-150 psig
(0–10.3 BAR)
(0–10.3 BAR)
Port Sizes
1/4", 3/8", 1/2"
NPT, BSPP, BSPT
NPT, BSPP, BSPT
Sensitivity
1/4" H2O (6.4mm)
Forward Flow Capacity
41 SCFM (1150 LPM)
@ 20 psig (1.4 BAR)
signal and 100 psig
(6.9 BAR) supply
@ 20 psig (1.4 BAR)
signal and 100 psig
(6.9 BAR) supply
Exhaust Capacity @ 5 psig (0.4 BAR) above setpoint
16 SCFM (425 LPM)
@ 10 psig (0.69 BAR)
above a 20 psig
(1.4 BAR) setpoint
@ 10 psig (0.69 BAR)
above a 20 psig
(1.4 BAR) setpoint
Temperature Range
-40 to 200˚F
(-40 to 93˚C)
(-40 to 93˚C)
Total Air Consumption @ Maximum Output
<12 SCFH (5.7 LPM)
Materials of Construction
aluminum, brass, carbon steel, stainless steel, acetal, nitrile
Supply pressure sensitivity
< 0.6 psig (0.01 BAR)
per 50 psig (1.4 BAR)
change in supply pressure
per 50 psig (1.4 BAR)
change in supply pressure
Maximum Signal
150 psig(10.3 BAR)
Ratio of Accuracy for 12 psig span
< 2% (1:1)
Find Your Part Number
Not sure? Call for help. Phone: 304-387-1200
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