Bellofram Air Regulators Type 78 Catalog Page
Air Regulators
Type 78
High Flow Air Regulator Series
Features
•Bellofram Rolling Diaphragm Provides
Low-Friction, Long Life Service
•Available in 3/8, 1/2, 3/4, and 1
NPT and BSPT
•Output Gauge Ports are 1/4 NPT
•Options: Low-bleed, Non-relieving, Tamper
Resistant Cover, Square-head Adjustment,
T-handle Adjustment, Epoxy Paint, Tapped
Supply Gauge Port, and Tapped Exhaust
•Mounting Brackets and Repair Kits Available
•Output Ranges are 0-2, 0-10, 0-30, 0-60,
0-125 PSIG 0-0.1, 0-0.7, 0-2.1, 0-4.1, 0-8.6 BAR
•Maximum Supply Pressure is Rated at
400 PSIG / 27.6 BAR
•Flow rates of well over 200 SCFM
Description
The Type 78 regulator is specifically designed
for applications that require large flow capability and accurate pressure control. This regulator
offers low droop, high accuracy, and fine
adjustment sensitivity. The use of a Bellofram
rolling diaphragm provides greater sensitivity
and improved accuracy. The Type 78 offers a
balanced pintle, which minimizes output pressure changes caused by fluctuations in supply
pressure. Careful design and quality materials
throughout assure long, trouble-free operation. The rugged die-cast zinc and aluminum
housings are pressure tested to assure safe
operation, and are designed to withstand harsh
and abusive environments. This durability is
attributed to a chemical conversion coating of
all cast components and a vinyl paint finish.
With a maximum supply pressure of up to 400
PSIG/27.6 BAR and output ranges up to 125
PSIG/8.6 BAR, the Type 78 can achieve flow
rates of well over 200 SCFM. It can be panel or
pipe mounted.
Operation
Marsh Bellofram’s Type 78 is a direct acting,
diaphragm-operated regulator. Once set to a
desired output pressure, this precision regulator
maintains the setting permanently. The range
spring, which has been compressed by the
adjustment knob, causes the pintle to move
downward, opening the supply valve and allowing air flow. The pressure builds up against the
control diaphragm until the supply valve closes.
This is the equilibrium or set pressure, which is
closely maintained under changes in operating
conditions in the following manner:
Downstream Pressure Drop
A drop in downstream pressure reduces the
diaphragm pressure force, upsetting the equilibrium condition. This unbalance causes the
supply valve to open until the pressure builds
up once more to the equilibrium condition.
Downstream Pressure Increase
An increase in downstream pressure acts on
the diaphragm, causing the relief seat in the
diaphragm assembly to lift and open. The
excess pressure is exhausted through the vent
port until the output pressure is restored to the
set point. The relief valve then closes.
Changes in Forward Flow
Under forward flow conditions, the range spring
force is balanced by the diaphragm pressure
force, with the supply valve open just enough
to maintain the required forward flow. When
high flow occurs, a specially designed aspirator helps maintain downstream pressure and
compensates for droop.
Sensitivity
Flow Capacity
Exhaust Capacity
Air Consumption
Effect of Supply Pressure on Regulated Pressure
Supply Pressure Max
Weight
Materials of Construction
Mounting Options
Type 78
Pressure Regulator Series
The Type 78 regulator is specifically
designed for applications that
require large flow capability and
accurate pressure control.
Type 78
Less than 1" water column
See Performance Curves
14 SCFM at 5 PSI / 0.3 BAR above 20 PSIG / 1.4 BAR
set point (0-30 PSIG / 0-2.1 BAR range unit)
less than 12 SCFH at 125 PSIG / 8.6 BAR
output pressure
less than ± 0.35 PSIG / 0.02 BAR for a supply
variation of 100 PSIG / 6.9 BAR
400 PSIG / 27.6 BAR
Approx. 5 lbs.
Body: Die Cast Zinc
Bonnet: Die Cast Aluminum Alloy
Knob: Phenolic Plastic, Plated Steel
Diaphragms: Nitrile Elastomers with Dacron Fabric
Other Internal Materials: Brass, Stainless Steel, and Zinc
Pipe or Panel
30
800.727.5646 • www.marshbellofram.com
Options
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 regulator, for some constant flow applications and where the gas
flowing through the regulator must not escape at the regulator. Non-relieving regulators should not be used for low or no flow applications.
Handle Options
“T” handle or square head.
Epoxy Paint
A gray epoxy finish applied to the body of the regulator to provide greater
resistance to corrosive environments.
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.
Tamper Resistant Cover
An aluminum tubular cover placed over a slotted head adjusting screw
and screwed on the bonnet of the regulator with a wrench, prevents
ordinary hand adjustments.
www.marshbellofram.com • 800.727.5646
Type 78 Typical Performance Curves
Droop Curve 3/8 NPT
PSIG BAR
6.2 90.00
5.5 80.00
4.8 70.00
4.1 60.00
3.4 50.00
2.8 40.00
Regulated PRessuRe
2.1 30.00
1. 4 20.00
0.7 10.00
0.0 0.00
SCFM 0 20 40 60 80 100 120 140 160 180 200
3
m
/HR 0 34 68 102 136 170 204 238 272 306 340
Droop Curve 1/2 NPT
PSIG BAR
6.2 90.00
5.5 80.00
4.8 70.00
4.1 60.00
3.4 50.00
2.8 40.00
Regulated PRessuRe
2.1 30.00
1. 4 20.00
0.7 10.00
0.0 0.00
SCFM 0 50 100 150 200 250
3
m
/HR 0 85 17 0 255 340 425
Droop Curve 3/4 NPT
PSIG BAR
6.2 90.00
5.5 80.00
4.8 70.00
4.1 60.00
3.4 50.00
2.8 40.00
Regulated PRessuRe
2.1 30.00
1. 4 20.00
0.7 10.00
0.0 0.00
SCFM 0 50 100 150 200 250 300
3
m
/HR 0 85 17 0 255 340 425 510
Droop Curve 1 NPT
PSIG BAR
6.2 90.00
5.5 80.00
4.8 70.00
4.1 60.00
3.4 50.00
2.8 40.00
Regulated PRessuRe
2.1 30.00
1. 4 20.00
0.7 10.00
0.0 0.00
SCFM 0 50 100 150 200 250 300
3
m
/HR 0 85 17 0 255 340 425 510
Supply Pressure set to 100 psig (6.9 BAR)
FoRwaRd Flow
Supply Pressure set to 100 psig (6.9 BAR)
FoRwaRd Flow
Supply Pressure set to 100 psig (6.9 BAR)
FoRwaRd Flow
Supply Pressure set to 100 psig (6.9 BAR)
FoRwaRd Flow
Air Regulators
31
Loading...