Types C471, C477 and C486
2
When tank and downstream pressure are nearly equal
after a few seconds, the excess flow spring pushes
open the main poppet (view #3) and the operating
lever can be moved to the full open position.
If tank pressure is greater than the valve’s outlet
pressure, the main poppet will remain in the closed
position. If valve outlet piping is closed off by other
valves, however, product bleeding through the pilot will
increase until it nearly equals tank pressure and the
main poppet opens.
Kalrez
®
is a mark owned by E.I. du Pont de Nemours and Co.
1. The pressure/temperature limits in this Instruction Manual and any applicable standard or code limitation should not be exceeded.
2. Product has passed Fisher™ testing for leakage down to -40ºF / -40ºC.
Specifications
The Specifications section on the following page shows specifications for Types C471, C477 and C486
internal valves.
Body Size and End Connection Styles
Types C471 and C477
Inlet:
2 or 3 in. MNPT / DN 50 or 80
Outlet:
2 or 3 in. FNPT / DN 50 or 80
Type C486
Inlet:
3 in. CL300 RF Flange / DN 80
Outlet:
3 in. FNPT / DN 80
Number of Outlets
Type C471:
2 (side and straight through)
Types C477 and C486:
1 (straight through)
Excess Flow Springs
Type C470 Half Coupling and Type C486 Flows:
2 in. / DN 50 Sizes:
105, 150 and 250 GPM /
397, 567 and 946 L/min
3 in. / DN 80 Sizes:
160, 265, 375 and 460 GPM /
605, 1003, 1419 and 1741 L/min
Type C470 Full Coupling Flows:
2 in. / DN 50 Sizes:
60, 80 and 130 GPM /
227, 302 and 492 L/min
3 in. / DN 80 Sizes:
120, 230, 320 and 380 GPM /
454, 870, 1211 and 1438 L/min
Maximum Allowable Inlet Pressure
(1)
400 psig / 27.6 bar WOG
Temperature Capabilities
(1)(2)
-20 to 150°F / -29 to 66°C
Approximate Weights
2 In. / DN 50 Sizes:
Type C471:
11 lbs / 5.0 kg
Type C477:
9 lbs / 4.1 kg
3 In. / DN 80 Sizes:
Type C471:
21 lbs / 10 kg
Type C477:
16 lbs / 7.3 kg
Type C486: 20 lbs / 9.1 kg
Construction Materials
Ductile Iron:
Body (Types C471 and C477)
Stainless steel:
Stem Assembly, Excess Flow
Spring, Spring Seat, Closing Spring, Disc Holder,
Disc Retainer, Screw, O-ring Seat, O-ring Retainer,
Cotter Pin, Spring, Shaft, Screen, Travel Stop,
Screen Cap, Bolt, Gasket and Lock Washer
Steel:
Body (Type C486), Cap Screw and
Operating Lever
Plated steel:
Nut, Washer, Bonnet Nut, Guide
Bracket and Cap Screw
Polyurethane (PU):
Rod Wiper
Polytetrafluoroethylene (PTFE):
Bushing,
Packing Adaptor and Packing Ring
Nitrile (NBR) (Standard Construction):
Main Disc, Bleed Disc and O-ring
Other Disc Material Available from
Factory:
Polytetrafluoroethylene (PTFE),
Fluorocarbon (FKM), Neoprene (CR),
Ethylene-Propylene (EPDM) and Kalrez
®
Principle of Operation
Refer to the schematic drawing, Figure 2. In view #1,
the valve is held closed by both tank pressure and the
valve’s closing spring. There is no leakage past the
resilient seats in the poppet to the valve outlet.
The valve is opened by moving the operating lever to
approximately mid-point in its 70° travel (view #2). This
allows the cam to place the rapid equalization portion
of the valve stem in the pilot opening, permitting
a larger amount of product to bleed downstream
than if the operating lever were moved to the full
open position.
