INSTRUCTIONS for
F-9528-G
October, 2006
HYDRAULIC
BACK-PRESSURE
VALVES
H-2, H-4 AND H-9 ACETYLENE
H-18 AND H-19 OTHER FUEL GASES
These INSTRUCTIONS are for experienced operators. If you are not fully familiar
with the principles of operation and safe practices for oxy-fuel gas equipment, we
urge you to read our booklet “Precautions and Safe Practices for Welding, Cutting and Heating”, Form 2035. Do not permit untrained persons to operate this
equipment. Do NOT attempt to operate this equipment until you have read and
fully understand these instructions. If you do not fully understand these instructions, contact your supplier for further information.
The hydraulic back-pressure valves covered by these instructions are listed by
Underwriter’s Laboratories only when using parts manufactured to ESAB Welding & Cutting Products specifications on file with Underwriter’s Laboratories,
Inc., and when they are used in the gas service for which they are designed and
listed. The use of other parts voids the manufacturer’s warranty.
SPECIFICATIONS
Hydraulic Maximum Recommended Gas Flow Rate Capacity
Back-Pressure @ Various Inlet Pressures in Cubic Feet Per Hour (m3/hrs.)
Valve Relief Liquid 3 psi 5 psi 10 psi 15 psi 25 psi 50 psi 75 psi 100 psi
Model Part No. Valve Capacity 0.21 bars 0.35 bars 0.69 bars 1.04 bars 1.73 bars 3.45 bars 5.18 bars 6.90 bars
For Acetylene
H-2 04B13 RV-28 7.1 pints 300 350 400 500 - - - -
H-4 04B84 RV-28 19.8 pints 600 (17) 700 (19.8) 800 (22.7) 1000 (28.3) - - - H-9 03P78 RV-28 (9.4 liters) 1800 (51) 2000 (56.6) 2500 (70.8) 3000 (85) - - - -
For Fuel Gases other than Acetylene
H-18 12P02 RV-28 600 (17) 700 (19.8) 800 (22.7) 1000 (28.3) - - - H-19 11P99 RV-28 19.8 pints 1800 (51) 2000 (56.6) 2500 (70.8) 3000 (85) - - - H-18 09P68 22X56 (9.4 liters) 600 (17) 700 (19.8) 800 (22.7) 1000 (28.3) 1400 (39.6) 2200 (62.3) 3100 (87.8) 3900 (110)
H-19 09P69 22X56 1800 (51) 2000 (56.6) 2500 (70.8) 3000 (85) 4000 (113) 6500 (184) 9000 (255) 11500 (326)
NOTES:
(3.4 liters) (8.5) (10) (11.3) (14.2) - - - -
1. The pressure drop through the hydraulic back pressure valves will vary between 0.5 and 1.0 p sig at maximum flow rate
capacity, the actual pressure drop depending upon the type of fuel gas and the inlet pressure.
2. Flow rates given for 25 through 100 psi may tend to draw liquid from the seal. Check input level frequently when operating at these pressure or with high flow rates.
Be sure this information reaches the operator.
Y ou can get extra copies through your supplier.
INTRODUCTION
These hydraulic back-pressure valves are for use on
medium-pressure piping systems between the main
supply line and the branch service lines. These valves
should not be used as st ation hydraulic valves. Detona-
tion pressure wave front s resulting from a backfire at
this point may be too severe to be stopped by a branch
line type hydraulic valve.
For use with acetylene there are three different sizes:
H-2 with a flow capacity of 500 cfh (14m3/h), H-4 with a
flow capacity of 1000 cfh (28 m3/h) and H-9 with a capacity of 3000 cfh (85 m3/h). Except for the size of the
hydraulic tanks and outlet piping (see Fig. 1) these two
are identical.
For use with fuel gases other than acetylene there are
also two different sizes: the H-18 with capacity of 1000
cfh (28 m3/h) and the H-19 with cap acity of 3000 cfh (85
m3/h). Except for the dif ferent nameplates the H-18 and
H-19 are identical to the H-4 and H-9 respectively . All
MAIN SUPPLY LINE
WLDED CONNECTION
STD. BLACK
STEEL NIPPLE
3/4 IN. RETURN BEND
BRANCH LINE TO
OUTLET STATIONS
but two of these hydraulics are equipped with R V-28 re-
lief valves which are set to relieve at 20 psi (1.4 bars).
However, since fuel gases such as hydrogen,
propane and natural gas as sometimes used at
pressures in excess of 20 psi, there is an H-18 (Part
No. 09P68) and H-19 (Part No. 09P69) equipped with
relief valve Part No. 22X56 which is set to relieve at
125 psi (8.6 bar).
IMPORTANT!! In addition to this booklet (9528), you will
find with your hydraulic another booklet, “Cold W eather
Care of Acetylene Generating and Distributing Equipment” (F-3088). Although it deals primarily with the installation and maintenance of acetylene equipment the
information also applies to fuel gases other than acetylene. You are urged to read it carefully before attempting to install your hydraulic.
II. PIPING AND FITTINGS
A. Piping
The size of the supply line piping from the manifold (or
acetylene generator) and the size of the branch line to
the service stations should be calculated for the operating flow leads and length of piping required. Consult your
ESAB representative for advice on this matter.
B. Valves, Union, and Connections
PLUG COCK OR
GLOBE TYPE VALVE
(SAME SIZE AS
BRANCH LINE)
MALLEABLE IRON
GROUND JOINT UNION
1 1/4" I.P.S. (H-4 H-18)
INLET
2 IN. IPP.S. (H-9 H-19)
6 1/2 IN.
RADIUS
6 FT. APPROX.
28 1/2 IN APPROX. (H-4 H-18)
37 5/8 IN APPROX. (H-9 H-19)
3 IN. MINIMUM
10 9/32 IN. O.D.
10 IN.
APPROXIMATE
HYDRAULIC SUPPORT
LIQUID LEVEL PLUG
(FILLING PLUG)
DRAIN PLUG
FLOOR LINE
GALVANIZED VENT PIPE
OUTLET
PLUG COCK OR
GLOBE TYPE VALVE
(SAME SIZE AS BRANCH
LINE)
STD. BLACK
STEEL NIPPLE
MALLEABLE IRON
GROUND JOINT
UNION
3/4 IN. MALLEABLE
IRON GROUND JOINT
UNION
(GALVANIZED)
RELIEF
VALVE
1 1/4" I.P.S. (H-4 H-18)
2 IN. I.P.S. (H-9 H-19)
6 FT. APPROX.
Fig. 1 - Installation Drawing
(parts shown in solid outline furnished with the equipment).
Valves, unions, and connection nipples on both the inlet
and outlet sides of the hydraulic should be the same
pipe size as the branch service line. Swage or bush from
this size to fit the inlet and outlet connections (3/4-in. on
the H-2, 1-1/4-in. on the H-4 and H-18, 2-in. on the H-9
and H-19).
C. Vent Pipe
This pipe must be galvanized and have galvanized fittings. It must be at least 3/4-in. in diameter. It should be
connected to the outlet on the side of the relief valve
with a 3/4-in. street elbow. It must be run separately to
out of doors and must be connected to vent pipes from
any other hydraulic. It should terminate outside the building not less than 12-ft. above the ground, remote from
windows or openings in the building and as far as possible from flues or chimneys. It s end must be fitted with
a return bend or elbow opening downward, preferably
screened to prevent obstruction. The vent pipe must be
installed without low points where moisture can collect.
III. INST ALLA TION
IMPORTANT: Before the hydraulic is connected to a
service line that has previously contained fuel gas, the
service line must first be completely shut of f from the
source of fuel gas, vented, and then purged of all traces
of fuel gas. Only carbon dioxide or nitrogen should be
used for purging.
2
3"
3/8" X 2"
BAR
WALL
LINE
3/8" U-BOLT
Fig. 2 - The sketch above shows the det ail of the hy-
draulic support and the method of installing it. Note that
about 2 or 3 inches clearance between the hydraulic
and the wall or supporting structure should be provided.
1. Install the hydraulic in a true vertical position with
the shut-off valves and union connections shown in
Fig. 1. Fit the connection nipples accurately so that
the union joints can be made up without straining
the connection joints at the hydraulic.
2. Support the hydraulic from a wall, building column,
or other rigid structure by means of a U-bolt or band
clamp placed around the lower chamber of the hydraulic. Use a spacer block or bracket to allow 2 or
3 inches clearance between the hydraulic and the
wall or supporting structure.
2. To Fill the Hydraulic Back-Pressure Valve or to
Check the Liquid Level, close both the inlet and
outlet shut-off valves. Operate the relief valve to relieve any pressure in the hydraulic through the vent
pipe. Remove the liquid-level plug and fill to the indicated level. Replace the liquid-level plug. Open
the shut-off valves.
3. The Liquid Level Should Be Checked Regularly,
and the correct liquid level maintained at all times.
The frequency with which the level should be
checked depends upon the conditions of service and
the liquid used in the hydraulic.
4. Preferred Solutions for Filling - These hydraulics
have a liquid capacity of 19.8 pints. The H-4 and H9 may be used with “wet” gas from an acetylene
generator or with “dry” gas from acetylene or piped
natural gas. The preferred filling solution for each
situation is fully described in the booklet “Cold
Weather Care of Acetylene Generating Equipment”,
packed with each hydraulic. These instructions apply equally to all types of fuel gases.
5. If a Flashback Should Occur, check the liquid level
before resuming service, making sure that the liquid is at the correct level, and refill if necessary.
V. MAINTENANCE
3. Remove the liquid-level plug and fill through this
opening to the indicated level. NOTE: For instructions as to the correct liquid to use, see the p aragraph, “Preferred Solutions for Filling” below.
4. After installing the hydraulic, leak test all joints at a
pressure of 20 psi with soapy water. The joints to be
tested include all joints of the hydraulic itself and all
joints made in fitting up and connecting the assembly to the fuel gas service lines. On new piping systems, the test should be applied with compressed
air or nitrogen before fuel gas is introduced into the
system. Nitrogen only should be used if the hydraulic was installed in piping previously in use for fuel
gas service. Never test for leaks with an open
flame.
If the test pressure causes the relief valve to vent enough
to reduce the test pressure, release the pressure, remove the vent pipe connection, and plug the relief valve
outlet until the test has been completed.
IV. OPERATION
1. To Admit Fuel Gas to the Hydraulic Back-Pressure Valve and to the Branch Line, open the shut-
off valves at the hydraulic inlet and at the hydraulic
outlet. TO SHUT OFF THE HYDRAULIC BACKPRESSURE VALVE, CLOSE BOTH SHUT -OFF
VALVES.
Before making any adjustments or repairs on the
hydraulic, close the shutoff valves at the hydraulic
inlet and outlet. Relieve the pressure in the hydraulic by venting it through relief valve.
No repairs should be made to the hydraulic backpressure valve proper except those which can be
made by simple replacement of parts. Only st andard
part s as listed should be replaced. If any other parts
require replacement, contact your ESAB representative.
1. To Drain the Hydraulic, remove the drain plug at
the bottom of the hydraulic.
2. Clean and Inspect the Swing-Check Valve at
Regular Intervals. When necessary , replace the
valve. To disassemble the hydraulic for such an inspection or replacement, make sure that the shutoff valves at the hydraulic inlet and outlet are closed.
Then disconnect the unions in the vent pipe and in
the outlet connection. Remove the hex nuts and bolts
that hold the cover plate and gasket to the hydraulic
shell. The shell can then be lowered away from the
inlet pipe, exposing the swing-check valve. Manually operate the swing-check valve to see that it
opens and closes freely. If necessary, wipe the valve
out with a clean cloth.
3
3. Open the Relief Valve Regularly at least once a
week by lifting the relief valve operating lever for an
instant to permit gas to escape through the vent pipe.
This guards against sticking of the valve.
4. Clean and Inspect the Relief Valve Regularly .
l
RV-27, R V-28, and R V-29 relief valves, which is
p
NOTE: Relief valve, Part No. 22X56 is used in place of
RV-29. The two valves are similar in function, but Part
No. 22X56 is preset to 125 PSI and is not adjustable.
(12) SCREW-6134-1542
(12) NUT-6330-0183
(04B84 ILLUSTRATED)
ELBOW -6834-4492
GASKET - 15S19
PLUG-6030-2998
NIPPLE
VALV E
VALVE ASSEMBLY-12B61
11P63 (RV-28)
22X56
6836-4495 (H-4, H-18)
TEE
6836-4077 (H-9, H-19)
6730-6475 (H-4, H-18)
6730-0225 (H-9, H-19)
PLUG-6070-2175
Hydraulic Back-Pressure Valve Assembly:
H-2 Part No. 04B13
H-4 Part No. 04B84 H-18 (RV-28) Part No. 12P02 H-19 (RV-28) Part No. 11P99
H-9 Part No. 03P78 H-18 (22X56) Part No. 09P68 H-19 (22X56) Part No. 09P69
HARDWARE
Part No. Description
6030-2998 1/2" Square Head Cast Iron Pipe Plug, Galvanized
6134-1542 1/2" — 13 x 1-1/2" Lg. Hex Head Steel Cap Screw (Cad. PI.)
6330-0183 1/2" — 13 Hex Steel Nut (Cad. PI.)
6730-6475 1-1/4" Short Steel Pipe Nipple, Galvanized
6836-4495 1-1/4" x 1-1/4" x 3/4" Std. Mall. Iron Banded Reducing Tee, Galvanized
6836-4077 2" x 2" x 3/4 Std. Mall. Iron Banded Reducing Tee, Galvanized
6834-4492 1-1/4" x 1" x 90° Galvanized Std. Banded Reducing Street Elbow
NOTE:
H-4, H-9, H-18, and H-19 hydraulic back-pressure valves manufactured before 1987 have a surge t ank mounted to
the top of the back-pressure valve tank. Units made after 1987 do not have this tank.
F-9528-G 10 / 2006 Printed in U.S.A.
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