< Marsh Bellofram Group of Companies < Bellofram Precision Controls < Relays < T-79 & T-79HR
Type 79 High Flow & Type 79HR Prescision Air Relays
Downloadable Files:

Relays Catalog Pgs (913 KB)

Type 79 High Flow & Type 79HR Precision Air Relays
  • Balanced Pintle
  • High Flow Capacity
  • Field Serviceable
  • Large Port Sizes Available
  • Air Piloted or Dome Loaded
  • 200 PSIG Output
  • Optional High Relieving (Type 79HR) and Valve Control (Type 79V)
Product Detail:
Marsh Bellofram Type 79 1:1 ratio high-flow precision pneumatic (air) relays are designed for applications where precise flow control is required. The Type 79 can achieve flow rates of well over 200 SCFM (5695 LPM). Use of a balanced pintle design allows the Type 79 to accurately control output pressure over wide flow and supply pressure variations, while minimizing output changes caused by supply fluctuations. A high relieving version, the Type 79HR, is also available, offering 25% additional exhaust capability.
A rugged design offers low droop, high accuracy and fine adjustment sensitivity. Use of a patented Bellofram rolling diaphragm provides greater sensitivity and improved accuracy, ensuring long, trouble-free operation over millions of cycles. Die-cast zinc and aluminum housings are pressure tested to ensure safe operation, along with chemical conversion coating of all cast components and a vinyl paint finish, facilitating use of the Type 79 within harsh and abusive environments. A version of the Type 79 for valve control applications, the Type 79V, is also available. The Type 79V utilizes soft exhaust seats to minimize air consumption, increased dead band to ignore valve oscillations, and an integral bypass valve that can be ‘tuned’ for optimum valve response. This relay can be pipe or bracket mounted.

Applications
• Clutch & Brake Controls
• Gas Flow Control
• Cylinder Bucking Control
• Tension Control
• Dancer (Calendar) Roll Loading
• Volume Boosting
• Valve Motor Loadingg
Part Numbers:
Port Size (NPT)
Range psig
Range
BAR
Part Number
Type 79
High Flow Capacity
1:1 Ratio
3/8
0-200
0-13.8
961-156-000
1/2
0-200
0-13.8
961-157-000
3/4
0-200
0-13.8
961-158-000
1
0-200
0-13.8
961-159-000
Type 79V
High Flow Capacity
1:1 Ratio
3/8
0-200
0-13.8
961-200-000
1/2
0-200
0-13.8
961-201-000
3/4
0-200
0-13.8
961-202-000
1
0-200
0-13.8
961-203-000
Type 79HR
High Flow Capacity
1:1 Ratio
3/8
0-200
0-13.8
962-378-000
1/2
0-200
0-13.8
962-378-100
3/4
0-200
0-13.8
962-378-200
1
0-200
0-13.8
962-378-300
Options:
Replace the last three digits of the part number with digits from the table below. If more than 2 combination needed, Consult Factory.
OPTION
1
2
5
6
7
1
 Low Bleed
001
051
061
071
2
 Non-Relieving  
002
052
062
072
5
 Epoxy Finish  
005
065
075
6
 Tapped Vent  
006
076
7
 Tapped Supply Port  
007

Epoxy Finish: Gray epoxy coating for greater corrosion resistance.
Low Bleed: Reduces steady-state air consumption by approximately 50%.
Non-Relieving: Used in applications where it is desirable to relieve pressure downstream of the relay. Non-relieving relays should not be used for low or no flow applications.
Tapped Vent (Exhaust): 1/4" NPT tapped port to allow for installation of plumbing to capture exhaust air.
Tapped Supply Gauge Port: 1/4" NPT tapped port is offered as a pressure tap for monitoring the inlet or upstream pressure supplied to the regulator.
   
Product Contact:
Sales Contact
Technical Contact
Specifications:
Maximum  Supply Pressure 400 psig (27.6 BAR)
Sensitivity 1" H2O (25mm)
Supply Pressure  Sensitivity <0.35 psig (0.02 BAR) per 100 psig (6.9 BAR) change in supply pressure
Flow Capacity >125 SCFM (3500 LPM) @ 20 psig (1.4 BAR) signal and 100 psig (6.9 BAR) supply
Exhaust Capacity 31 SCFM (875 LPM) @ 5 psig (0.35 BAR) above a 20 psig (1.4 BAR) setpoint

T79HR-39 SCFM (3500 LPM) @ 5 psig (0.35 BAR) above a 20 psig (1.4 BAR) setpoint
Temperature Limits -40 to 200ºF
(-40 to 93ºC)
Air Consumption <12 SCFH
(5.7 LPM)
Port Size 3/8, 1/2, 3/4, 1 NPT, BSPP, BSPT
Output Pressure Range 0-200 psig
(0-13.8 BAR)
Maximum Signal 200 psig (13.8 BAR)
Weight 4.5 lb. (2.0 kg.)
Ratio of Accuracy for a 12 psig span <1.5%
• Marsh Instruments • BelGAS • Bellofram Diaphragm • Automatic Timing & Controls • Diversified Electronics • DigiTec Division • Thermo-Couple Products