Page 1
SERIES
INSTALLATION / OPERATION / MAINTENANCE
38VB
Vacuum Breaker W/Optional Air Release Valve For Water and Sewage
1/2” - 3” Threaded 4” - 10” Flange Style
INTRODUCTION
Cla-Val Vacuum Breaker Valves are designed to perform years of
trouble free operation and service life. The valve functions to open,
allowing air to enter a pipeline, tank or system to prevent vacuum
forming. Sizes 1/2” thru 3” have threaded inlet and outlet, 4” and
larger have a flanged inlet as standard and a threaded, flanged or
plain outlet covered by a steel hood.
Standard Vacuum Break valves
have an internal spring with a fixed
rate to open between 1/4 - 1/2 PSI.
See fig 1. and Fig 1A For Vacuum
Breaker adjustability, external
spring with adjusting nut is supplied see Fig.3. For Sewage, a
clear flow area body with external
spring and flushing valves is supplied. see fig.4
Vacuum Breaker Valves in 2 Style:
HOW THEY WORK
The vacuum breaker valve (large orifice combined with Air Release (small
orifice) are both normally closed but
when installed at points where vacuum
can occur. they work as follows:
The large orifice valve will open under
vacuum, allowing air into pipeline to fill
the void, created by vacuum. Next it
instantly closes trapping air, that is
compressed, there by cushioning
return of positive fluid pressure, to prevent severe pressure surge and water
hammer,
Optionally the small orifice Air Release
Valve will also open, due to vacuum
and stays open acting as the outlet, to
slowly release the trapped air, from the
system until normal pressure is
achieved at which point the small
orifice closes.
RECEIVING AND STORAGE
Immediately inspect shipment upon receipt for damage in transit and
report same to carrier.
Store valves in a dry area until ready to install to prevent damage
when storing longer than six months coat rubber seat with FDA
approval grease to preserve resiliency.
Optional
Air Release
Valve
SMALL
ORIFICE
AIR RELEASE
OPEN
CLOSED
VACUUM
BREAKER
LARGE
ORIFICE
AIR
OUT
AIR
IN
Large
Orifice
Fig 1A
AIR RELEASE
small
orifice
VACUUM
BREAKER
LARGER
ORIFICE
For Sewage
Fig. 4
STANDARD
ADJUSTABLE
Valve Shown in
Open Position
Fig.4
Page 2
VALVE CONSTRUCTION FLANGE STYLE
Vacuum breaker valve bodies are heavy cast iron. The seat & plug of the
flange style valves are bronze Fig 1. The plug of the flange style is the
only moving part when the valves open. The springs are annealed an
polished for many years of compression cycle life. see table A&B for
materials.
Materials & Part names are the same for FLG Styles: Fig. 1, Fig. 3, &
Fig. 4. Specify Fig. No. and size when ordering parts for series 38VB
flanged styles.
Part Name
Body
Seat
Plug
Spring
Bushing
Seat Retaining Screws
Gasket
Ring Plate
Bolt and Nut Assembly
Bird Screen
Threaded Set Collar
Hood Assembly
Hood Retaining Screws
Hood Washer
Spring Retainer
Detail No.
1
2
3
4
5
6
8
10
11
12
18
23
24
25
36
Material
Cast Iron
Bronze with
Buna-N
®
Seal
Bronze
Stainless Steel
Bronze
Stainless Steel
Compressed
Non-Asbestos Fiber
Steel
Steel, Zinc Plated
Stainless Steel
Steel, Zinc Plated
Steel
Steel, Zinc Plated
Steel, Zinc Plated
Steel
* Not included in 2” & 2.5” Size
Table A Parts List
Valve Construction Threaded Style
Threaded style vacuum breaker 1/2”-3” size, all internal
parts,are stainless except valve seat is Buna-N
®
. The float and
guide are the only moving parts assuring long life with minimum maintenance. See Table B for standard material details.
Detail No.
1
2
3
4
5
6
7
8
9
14
10
* Recommended Spare Parts
Table B Parts List
Part Name
Body
Cover
Baffle
Seat
Float
Gasket
Cover Bolt
Retaining Screw
Guide Bushing
Pipe Plug
Spring*
Material
Cast Iron
Cast Iron
Ductile Iron
Buna-N
Stainless Steel
Non-Asbestos
Alloy Steel
Stainless Steel
Stainless Steel
Iron
Stainless Steel
STANDARD
For
Sewage
ADJUSTABLE
Valve Shown in
Open Position
Fig.4
2
8
4
7
6
3
CLOSED
5
10
20
9
1
14
THREADED
STYLE
FIG. 2
AIR
IN
OPEN
Page 3
INSTALLATION/OPERATION
Installation of the vacuum breaker valve is important for
its proper operation. Valves must be installed in a vertical
position with the inlet down on high points of a pipeline or
tank, where vacuum conditions are anticipated. A full
ported shut-off valve, under the valve, should be installed
for future inspection or maintenance.
The vacuum breaker valve will open to allow air to reenter the pipeline or tank for any reason that the pipeline
or tank is drained. Allowing air re-entry will prevent vacuum forming that would otherwise cause pipeline or
tank to collapse and also prevent water column separations which can cause pressure surges and damage as
the water column rejoins.
SETTING THE BREAKER VALVE
The standard vacuum breaker Fig.1 and Fig.1A above
are set from the factory to open between 1/4” & 1/2” PSI.
This is setting is not adjustable. The vacuum breaker having
an external spring for water or for sewage is set at the
factory per customers specification. After installation the
V acuum breaker can be re-adjusted to suit actual operating conditions simply by tightening or loosening #18 seat
collar Fig 3.
SEWAGE APPLICA
TIONS
The Cla-Val Vacuum Breaker for sewage has clear flow
unobstructed body to prevent clogging. This valve is supplied
with (2) 1” full flow valves for flushing out the valve
periodically as may be required.
FLUSHING PROCEDURE FIG. 4
1. Shut the isolation valve under the vacuum breaker
(As provided by others).
2. Depressurize the vacuum breaker by slowly opening
one of the full flow valves mounted on the valve body.
3. Flush with pressurized water from a water tanker or
remove the vacuum from the pipeline or tank and take
it to the maintenance shop for cleaning.
4. During flushing, push down the external spring to
create a cleansing action around the plug #3 and thru
the sea. #2.
MAINTENANCE
Cla-Val Vacuum Breakers operate automatically and
no regular lubrication or maintenance is required.
Avisual inspection annually to observe if any leakage
is occurring by simply removing the hood #22 will be
more than adequate.
TYPICAL INSTALLATION
VACUUM
BREAKER
LARGER
ORIFICE
STANDARD FLANGE STYLE
SMALL
ORIFICE
AIR RELEASE
OPEN
CLOSED
VACUUM
BREAKER
LARGE
ORIFICE
AIR
OUT
AIR
IN
Large
Orifice
Fig 1A
Fig 1.
STANDARD THREADED STYLE
ADJUSTABLE
Valve Shown in
Open Position
For Sewage
Fig.4
Page 4
DISASSEMBLY
The Vacuum Breaker Valve may be disassembled without
removal from the pipeline or may be removed from the line
for more convenience. Work on the valve should be performed by a skilled mechanic. Refer to figures 1,3,4 and 2
W
ARNING: Drain or depressurized valve before
removing the cover completely or
pressure released may cause bodily harm.
1. Close inlet shut-off valve. Open drain valve Fig.4 or
remove drain plug Fig.2 (14) or remove cover bolts (11)
Fig.3 on the top cover (10).
2. Pry cover (10) loose and lift off valve body.
3. Remove seat retainer screws (6) and inspect seat for
cracks in rubber or wear in sealing surface.
4. Lift plug (3) from body (1) and guide bushing (5) and
inspect for wear.
5. Examine gasket (8) and replace if damaged.
6. Clean and inspect parts. Remove all foreign material from
body and cover. Replace worn parts as may be observed.
RE-ASSEMBLY
All parts must be cleaned and gasket surfaces should be
cleaned with a stiff wire brush in the direction of serration or
machine marks. Worn parts, gasket and seals should be
replaced during reassembly.
1. Place plug, 3 spring 4 and seat (2) in the body and retain
with round head seat fastener (6).
3. Place gasket over flange. The gasket must cover the seat
(2) for proper seat retention.
4. Place ring plate (10) on valve body on the flange and
install flange bolts and nuts per Table D cover and flange
bolt torques.
5. Using a cross tightening method, tighten to the torques
listed in table 3 in three increments
6. Place valve back in service. slowly open the inlet isolation
valve. Check flanges for leakage.
Bolt Size
Torque (Ft-Lbs.)
1/2” 45
5/8” 93
3/4” 150
7/8” 202
1” 300
1-1/8” 450
1-1/4” 650
1-3/8” 800
TABLE D. COVER AND FLANGE BOLT TORQUES
PARTS AND SERVICE
Parts and Service are available from your local representative or the factory. Make note of the valve size, series No,
and serial No. located on the valve nameplate and contact:
Cla-Val • 1701 Placentia Ave. • Costa Mesa, CA 92627-4475
Phone: 949-722-4800
Fax: 949-548-5441
A sales representative will quote prices for parts or service.
N-AV 38VB (R-11/01)
Loading...