cashco BQ Instruction manual

I. DESCRIPTION AND SCOPE
The Model BQ is a back pressure relief regulator used to control upstream (inlet or P1) pressure. Side inlet and flow-thru
connections are 1/4", 3/8", and 1/2" NPT (DN8, DN10, DN15); outlet (bottom discharge) connection is always 1/2" NPT (DN15).
With proper trim utilization, the unit is suitable for liquid, gaseous, or steam service. Refer to Technical Bulletin BQ-TB for design
conditions and selection recommendations.
MODEL BQ
BACK PRESSURE / RELIEF REGULATOR
II. INSTALLATION
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-BQ
05-04
6. Clean the piping of all foreign material including chips,
welding scale, oil, grease and dirt before installing the
regulator. Strainers are recommended.
7. In placing thread sealant on pipe ends prior to en-
gagement, ensure that excess material is removed
and not allowed to enter the regulator upon startup.
8. Flow Direction: Install so the flow direction matches
the arrow cast on the body. Connect the inlet pressure
to the body side connection(s). Fluid will relieve out of
the bottom connection. The double inlet connections
are for in-line installation (plug one side connection if
in-line installation is not required).
9. Regulator may be installed in a vertical or horizontal
pipe. If it is a steam system, ensure the piping is properly
trapped and vented.
Supply
@ P1
SRVPI
Model BQ
BP/Relief
Regulator
Bypass
System
Demand
P2
Discharge
Recommended Piping Schematic
for Back Pressure/Relief Station
CAUTION
This is not a safety device and must not be substituted for a code approved pressure safety relief valve or a rupture disc.
SECTION II
SECTION I
WARNING
The maximum inlet pressure is equal to 1.5 times the larger
number of the stated range spring on the nameplate, and is
the recommended “upper operative limit” for the sensing
diaphragm. Higher pressures could damage the diaphragm.
(Field hydrostatic tests frequently destroy diaphragms.
DO NOT HYDROSTATIC TEST THRU AN INSTALLED UNIT;
ISOLATE FROM TEST.)
CAUTION
Installation of adequate overpressure protection is recom-
mended to protect the regulator from overpressure and
all downstream equipment from damage in the event of
regulator failure.
1. An inlet block valve should always be installed.
2. If service application is continuous such that shutdown
is not readily accomplished, it is recommended that
an inlet block valve, outlet block valve, and a manual
bypass valve be installed.
3. Pipe unions should be installed to allow removal from
piping.
4. An inlet pressure gauge should be located approximately
ten pipe diameters upstream and within sight. An outlet
pressure gauge is optional.
5. All installations should include an upstream relief device
if the inlet pressure could exceed the pressure rating of
any equipment or the maximum inlet pressure rating of
the unit.
CAUTION
For welded installations, all internal trim parts, seals and
diaphragm(s)mustberemovedfromregulatorbodypriorto
welding into pipeline. The heat of fusion welding will dam-
age non-metallic parts if not removed. NOTE: This does
not apply to units equipped with extended pipe nipples.

IOM-BQ2
a. Recommended installation is with the spring chamber
directed upwards.
b. No corrosive fluid should be utilized for spring cham-
ber loading.
c. System operation should ensure that loading pres-
sure (PLOAD) not exceed inlet pressure (P1); internal
diaphragm damage may occur if this operational
mode occurs.
11. Regulators are not to be direct buried underground.
12. For insulated piping systems, recommendation is to not
insulate regulator.
13. Spring Chamber Vent Tap - Option -25: Pipe spring
chamber vent opening to remote location. Orient so as
not to take on rainwater.
10a. Basic Regulator - (Refer to Figure 1): Regulator may
be rotated around the pipe axis 360°. Recommended
positions are with the spring chamber vertical upwards,
or horizontal. Orient such that the spring chamber vent
hole does not collect rainwater or debris.
10b. Cryogenic Regulator - Option -5 or -36 (Figure 2):
a. Recommended installation is with spring chamber
hanging directly below the body in a vertical down-
wards orientation. Allow water to drain; i.e. melting
frost, rain water.
b. Recommend inert purge gas to spring chamber
through vent hole and out drain hole.
10c. Differential Regulator - Option -1+6 (Refer to Figure 3).
7. Slowly open the outlet (downstream) block valve ob-
serving the inlet (upstream) pressure gauge. Determine
if the regulator is flowing. If not, slowly rotate the regula-
tor adjusting screw counterclockwise (CCW) until flow
begins.
8. Continue to slowly open the outlet (downstream) block
valve until fully open.
9. Observing the inlet (upstream) pressure gauge, rotate
the adjusting screw clockwise (CW) slowly until the inlet
pressure begins to rise. Rotate CW until the desired
setpoint is reached.
10. Continue to slowly open the inlet (upstream) block valve.
If the inlet (upstream) pressure exceeds the desired
setpoint pressure, rotate the adjusting screw (CCW)
until the pressure decreases.
11. When flow is established steady enough that both the
outlet and inlet block valves are fully open, begin to
slowly close the bypass valve if installed.
12. Develop system flow to a level near its expected normal
rate, and reset the regulator setpoint by turning the
adjusting screw CW to increase inlet pressure, or CCW
to reduce inlet pressure.
13. Reduce system flow to a minimum level and observe
setpoint. Inlet pressure will rise from the setpoint of Step
9. (Ensure that this rise does not exceed the stated upper
limit of the range spring by greater than 50% i.e. 30-80
psig (2.07 - 5.52 Barg) range spring, at maximum flow
the inlet pressure should not exceed 1.5 x 80 (5.6 Barg)
or 120 psig (8.3 Barg). If it does, consult factory.)
14. Increase flow to maximum level if possible. Inlet (up-
stream or P1) pressure should rise. Readjust setpoint
as necessary at the normal flow rate.
IV. STARTUP
*NOTE:Systemssequencingoperationsatstartup,normalopera-
tion, failure mode(s), and shutdown must assure that the pressure
(PLoad) on the spring chamber does not exceed the pressure regis-
tering on the wetted side of the diaphragm. Should this "pressure
reversal" occur, particularly to metal diaphragms, the diaphragm
may be permanently damaged and cause improper operation.
P1> PLoad
Pressure reversal is normally caused by the inlet pressure
to a regulator being interrupted (automatically or manually).
1. Ensure that the proper range spring is indicated to be
within the regulator by inspection of the unit's nameplate.
Apply setpoint pressures that are only within the stated
range.
2. When stating direction of rotation of the adjustment screw,
the view is with respect to looking down towards the
adjusting screw or its normal location.
3. Start with the block valves closed.Abypass valve may be
used to maintain inlet pressure in the upstream system
without changing the following steps.
4. Remove closing cap, if installed. Relax the range spring
by turning the adjusting screw counterclockwise (CCW)
a minimum of three (3) full revolutions. This reduces the
inlet (upstream) pressure setpoint.
5. If it is a “hot” piping system, and equipped with a by-
pass valve, slowly open the bypass valve to pre-heat
the system piping and to allow slow expansion of the
piping. Ensure proper steam trap operation if installed.
Closely monitor inlet (upstream) pressure, via gauge, to
ensure not over-pressurizing. NOTE: If no bypass valve
is installed, extra caution should be used in starting up
a cold system; i.e. do everything slowly.
6. Crack open the inlet (upstream) block valve.
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register on
the diaphragm. The registering pressure is the inlet,
P1or upstream pressure. The range spring opposes
diaphragm movement.As inlet pressure drops, the range
spring pushes the diaphragm down, closing the port;
as inlet pressure increases, the diaphragm pushes up
and the port opens.
2. A complete diaphragm failure will cause the outlet
process fluid to mix with the loading fluid.
SECTION III
SECTION IV

IOM-BQ 3
V. SHUTDOWN
1. On systems with a bypass valve, and where system
pressure is to be maintained as the regulator is shut
down, slowly open the bypass valve while closing the inlet
(upstream) block valve. Fully close the inlet (upstream)
block valve. When on bypass, the system pressure must
be constantly observed and manually regulated. Close
the outlet (downstream) block valve.CAUTION
2. Relax range spring (11) by turning adjusting screw
(13) CCW until removed from spring chamber (2).
2. If the regulator and system are both to be shutdown,
slowly close the inlet (upstream)block valve. Close the
outlet (downstream) valve only if regulator removal is
required.
VI. MAINTENANCE 3. Draw or embed a match mark between body casting
(1) and spring chamber casting (2) along flanged
area.
4. Remove all flange nuts (8) and flange bolts (7).
5. Remove spring chamber (2), range spring (11) and
spring button (12).
6. Remove the diaphragm subassembly consisting
of the piston cap screw (9), pressure plate (10),
diaphragm(s) (4), piston (3.1) and piston gasket
(5). NOTE: Refer to the quantity of diaphragm(s)
(4) incorporated in the bill of materials listing.
Depending on inlet pressure level, multiple metal
diaphragms may be “stacked”.
A. General:
1. Maintenance procedures hereinafter are based
upon removal of the regulator unit from the pipe-
line where installed.
2. Owner should refer to ownerʼs procedures for
removal, handling, cleaning and disposal of non-
reuseable parts, i.e. gaskets, etc.
3. Refer to Figure 1 for basic construction, Figure 3 for
differential construction and Figure 2 for cryogenic
construction. For a blow-up of the composition seat
trim, see Figure 4.
4. When counter clockwise (CCW) or clockwise (CW)
rotations are indicated, they are with respect to:
a. Spring Chamber - as viewed from above look-
ing down towards the closing cap or its normal
location.
b. Body - as viewed looking into the body cavity
with the spring chamber removed.
B. Diaphragm Replacement:
1. Securely install the body (1) in a vise with the spring
chamber (2) directed upwards.
7. To disassemble the diaphragm subassembly,
place piston (3.1) in a vise and rotate piston cap
screw (9) CCW. NOTE: Recommend using lead
jaws when placing the piston in a vise, so as not
to damage the piston grooves.
8. Separate all parts (3.1, 4, 5, 9 and 10) and clean
piston gasket (5) surface on piston (3.1) if piston is
to be reused. NOTE: No piston gasket (5) utilized
for composition diaphragm.
9. Inspect pressure plate (10) to ensure no defor-
mation due to over-pressurization. If deformed,
replace.
10. Remove diaphragm gasket (6) for metal diaphragm.
NOTE: No diaphragm gasket (6) utilized for compo-
sition diaphragm.
Diaphragm Subassembly
SECTION V
CAUTION
Do not walk away and leave a bypassed regulator unat-
tended!
SECTION VI
WARNING
SYSTEM UNDER PRESSURE. Prior to performing any
maintenance, isolate the regulator from the system and
relieve all pressure. Failure to do so could result in per-
sonal injury.
WARNING
SPRING UNDER COMPRESSION. Prior to removing flange
bolts, relieve spring compression by backing out the ad-
justing screw. Failure to do so may result in flying parts
that could cause personal injury.

IOM-BQ4
15. Insert the diaphragm subassembly into the body
(1). Rotate the assembly to ensure that the piston is
not binding in the cylinder. If necessary, buff piston
with Scotch-Brite ® or equivalvent.
16. Place the range spring (11) on to the pressure plate
(10).
17. Place multipurpose, high temperature grease into
depression of spring button (12) where adjusting
screw bears. Set spring button (12) onto range
spring (11); ensure spring button (12) is laying
flat.
18. Aligning the matchmarks, place spring chamber
(2) over the above stacked parts. Install all bolts
(7) and nuts (8) by hand tightening. Mechanically
tighten bolting (7) (8) in a cross pattern that allows
spring chamber (2) to be pulled down evenly. Rec-
ommended torques are as follows:
NOTE: Never replace bolting (7)(8) with just any
bolting, if lost. Bolt heads and nuts are marked
with specification identification numbers. Use only
proper grades as replacements.
19. Reinstall adjusting screw (13) with locknut (14).
20. Soap solution test around bolting (7) (8) and body
(1) and spring chamber (2) flanges for leakage.
Ensure that an inlet pressure is maintained during
this leak test of at least mid-range spring level;
i.e. 20-75 psig range spring, 50 psig test pressure
minimum.
11. Clean body (1) and diaphragm flange. NOTE: On
regulators originally supplied as “cleaned for oxygen
service”, Option -5, -36 or -55, maintenance must
include a level of cleanliness equal to Cashco clean-
ing standard #S-1134. Contact factory for details.
12. Place diaphragm gasket (6) on body (1) flange, if
required.
13. Reassemble diaphragm subassembly by placing
piston (3.1) in a vise (recommend using lead jaws
with vise). Assemble parts on piston cap screw (9)
as follows: pressure plate (10), diaphragm(s) (4),
and piston gasket (5), if required. NOTE 1: Apply
a light coat of gasket sealant to gasket. NOTE
2: Ensure that the pressure plate is placed with
curved outer rim down next to the diaphragm (4)
surface.
14. Apply thread sealant compound to the threads
of the piston cap screw (9) and thread into piston
(3.1). Rotate pistion cap screw (9) CW and tighten
to the following torques.
C. Special Instructions for Diaphragm Replacement:
1. For the Option -1+6 Differential Construction, reas-
semble the diaphragm subassembly in Sub-Section
B. Step 12 as follows: assemble parts on piston
cap screw (9), pressure plate (10), piston gasket
(5), diaphragm(s) (4), piston gasket (5), and pusher
plate (23). Refer back to Step 13 for "NOTES".
2. For metal diaphragm(s) (4) only, install a second
diaphragm gasket (6) on the top side of the dia-
phragm (4). NOTE: Clean the diaphragm flange
area of the spring chamber (2) thoroughly before
assembly.
3. Utilize a new lock nut seal (22) when installing the
adjusting screw (13) and locknut (14).
4. Install new closing cap gasket (21), reinstall closing
cap (20).
D. Trim Replacement:
1. Trim removal requires that diaphragm subassembly
be removed. Refer to previous procedure Section
VI.B.
2. Using a deep socket with a 24 inch (600mm) le-
ver length, place the socket over the cylinder (3.2)
hex surfaces. Rotate CCW to remove the cylinder
(3.2).
3. Inspect inside surface of cylinder (3.2) at three
points:
a. Seat ring for erosion/wear on seating sur-
faces.
b. At metal-to-metal surface between body and
cylinder (3.2). If wear exists here, consult fac-
tory.
c. Where the piston (3.1) ribbed guides bear
(guide zone).
If wear is significant at any of these points, replace
the piston/cylinder assembly (3).
4. Clean the body (1) cavity. Clean all parts to be re-
used. NOTE: On regulators originally supplied with
Option -55, “special cleaned”, maintenance must
include a level of cleanliness equal to Cashco Speci-
fication #S-1134. Contact factory for details.
5. Use special care cleaning the flat mating surfaces
of the body (1) and cylinder (3.2) shoulder, as this
pressurized joint is metal-to-metal without a gas-
ket.
6. Lubricate the cylinder (3.2) threads lightly with
thread sealant, insert the cylinder (3.2) into the
body (1) and screw CW until tightly seated. Re-
install diaphragm subassembly per Section VI.B.,
Diaphragm Replacement.
7. Bench test unit for suitable operation. NOTE:
Regulators are not tight shutoff devices. Even if
pressure falls below setpoint, a regulator may or
DIAPHRAGM TYPE TORQUE
Metal 15 ft-lb (20 N-m)
Composition 12 ft-lb (16 N-m)
REGULATOR SIZE BOLT SIZE METAL DIAPHRAGM COMP. DIAPHRAGM
ALL 5/16" 15 ft-lb (20 N-m) 12 ft-lb (16 N-m)

IOM-BQ 5
VII. TROUBLE SHOOTING GUIDE
may not develop bubble tight shutoff. In general,
tighter shutoff can be expected with a composition
seat.
8. Soap solution test around body (1) flange for leak-
age. Test pressure should be the maximum allowed
by the range spring at the inlet.
SECTION VII
Possible Causes Remedies
A. Oversized regulator; inadequate rangeability. A1.
A2.
A3.
A4.
A5.
Check actual flow conditions, resize regulator for mini-
mum and maximum flow.
Tighten flange bolting.
Increase flow rate.case and washer. Install new thread
Decrease regulator pressure drop; decrease inlet pres-
sure by placing a throttling orifice in inlet piping union.
Install next step higher range spring.
Before replacing regulator, contact factory.
B. Worn piston/cylinder; inadequate guiding. B1. Replace trim.
1. Erratic Operation; chattering
2. Regulator inlet (upstream) pressure too high:
Possible Causes Remedies
A. Regulator undersized. A1.
A2.
Confirm by opening bypass valve together with regulator.
Check actual flow conditions, resize regulator; if regulator
has inadequate capacity, replace with larger unit.
B. Plugged trim. B. Remove trim and check for plugged holes in cylinder.
C. Incorrect range spring (screwing out CCW of adjusting
screw does not allow bringing pressure level to a stable
and proper level).
C. Replace range spring with proper lower range.
D. Too much build (rise). D1.
D2.
D3.
Review rise (build) expected.
Contact factory.
If -1+6 differential, ensure that pressure reversal has not
permanently deformed the metal diaphragm.
E. Restricted diaphragm movement. E. Ensure no moisture in spring chamber at temperatures
below freeze point. Ensure no dust or debris entering
vent opening. If rainwater or debris can enter, reorient
spring chamber.
Possible Causes Remedies
A. Normal-life diaphragm failure. A. Replace diaphragm.
B. Abnormal short-life diaphragm failure. B1.
B2.
B3.
Can be caused by excessive chattering. See No. 1 to
remedy chatter.
Can be caused by corrosive action. Consider alternate
diaphragm material.
Upstream (inlet) pressure buildup occurring that over-
stresses diaphragms. Relocate regulator or protect with
safety relief valve.
3. Leakage through the spring chamber vent hole.
Possible Causes Remedies
A. Plugged spring chamber vent. A. Clean vent opening.
B. Fluid too viscous. B. Heat fluid. Contact factory.
4. Sluggish operation.

IOM-BQ6
b. Regulator “Model” identifier.
c. Size (may have to observe body tap).
d. Spring range.
e. Trim designation number (if available).
Step 2. Determine construction of trim.
a. Metal or composition (soft) seat?
b. Is 316 SST needed over standard 416 SST?
c. What material are the gaskets? (Our standard non-
asbestos is light gray in color, and TFE is fawn.)
Step 3. With the information from Steps 1 and 2 above, contact
your local Cashco, Inc., Sales Representative for the
proper identification numbers to use, and the parts
costs.
METHOD C - NO PRODUCT CODE AVAILABLE
- ASSEMBLED REGULATOR IN SERVICE.
Step 1. Determine all available information from metal tag using
Step 1, Method B.
Step 2. Contact your local Cashco, Inc., Sales Rep with the
above information.
Step 3. Sales Representative will contact the factory to de-
termine the original internal construction. Factory will
relay information to the Sales Representative.
Step 4. Await the Sales Representativeʼs return contact with
the proper part numbers and cost.
SECTION VIII
VIII. PARTS ORDERING INFORMATION
There are three methods to obtain parts ordering information/numbers. These methods are listed below, in order of ease of
entering. The least expensive method is to utilize parts in kits where possible.
METHOD A - USE OF PRODUCT CODE.
Step 1. If available, obtain the 18 character product code num-
ber from:
a. The Bill of Materials sheet attached herein
b. The metal tag attached to the regulator.
NOTE: Some regulators may not have the product
code located on the metal tag.
Step 2. Identify which kits or parts are desired from the fol-
lowing:
a. The Bill of Materials sheet attached herein, or refer
to the cross-sectional drawings.
b .Standard maintenance parts for a basic regulator
(no options) are included in the Parts Kit Number
table below. Kit “A” contains seal(s), diaphragm(s)
and gasket(s). Kit “B” contains trim replacement
parts plus seal(s), diaphragm(s) and gasket(s).
Step 3. Contact your local Cashco, Inc., Sales Representative
and specify the product code number along with a
description of any parts not included in the kits below.
Costs of required parts (and kits) can be given by the
Sales Representative.
METHOD B - NO PRODUCT CODE AVAILABLE
- DISASSEMBLED REGULATOR.
Step 1. Determine all available information from regulator's
metal tag.
a. Serial number (5-digit).
7 --
The shaded parts kits numbers below represent an abbreviated
identification number for a basic regulator (no options).
MODEL BQ
PARTS KIT NUMBERS
(KIT NOS. SHADED)
TRIM
DISIG. NO.
KIT
ABBR.
SIZE
1/4", 3/8" & 1/2" (DN8, 10 &15)
B0 & B5 A 1B2-ABOK-A
BO B 1B2-BBOK-A
B2 A 1B2-AB2K-A
B 1B2-BB2K-A
B5 B 1B2-BB5K-A
S1 & S36 A 1B2-AS1K-A
S1 B 1B2-BS1K-A
S36 B 1B2-B36K-A

IOM-BQ 7
MODEL BQ
COLOR-CODED SPRING CHART
NOTE: If it becomes necessary to change
a regulator's range spring and install a new
spring for a different pressure range, A NEW
CASHCO, INC., NAMEPLATE MUST BE
AFFIXED TO THE REGULATOR. Contact
your local Cashco Sales Representative and
specify the new pressure range and the
serial number off the existing name plate.
They will contact the factory who will review
unit's original internal construction and de-
termine new operating pressure limits.Await
the Sales Representative's return contact
with the proper part numbers and cost.
Figure 3: Option -1+6 Differential,
Metal Seat Design (includes
Option -1 Closing Cap)
Figure 4:
Composition Seat
Item No. Description
1 Body
2 Spring Chamber
3 Trim (Cylinder/Piston/Seat)
3.1 Piston
3.2 Cylinder
4 Diaphragm
5 Piston Gasket
6 Diaphragm Gasket
7 Hex. head Cap Screw (Flange Bolting)
8 Nut (Flange Bolting)
9 Piston Cap Screw
10 Pressure Plate
11 Range Spring
12 Spring Button
13 Adjusting Screw
14 Adjusting Screw Lock Nut
15 Nameplate
20 Closing Cap
21 Closing Cap Gasket
22 Lock Nut Seal
23 Differential Pusher Plate
(NOTE: Mount in Horizontal line with
Adjusting Screw down as shown.)
Figure 1: Standard Model BQ,
Metal Seat Design
Figure 2: Option -5 or -36 Cryogenic,
Metal Seat Design
SIZE
STANDARD UNIT
STEEL PLATED SPRING
CRYOGENIC -5 OR -36 OPTION
STAINLESS STEEL SPRING
RANGE SPRING
psig PART NUMBER/COLOR RANGE SPRING psig PART NUMBER/COLOR
ALL
5 - 15 830-69-5-02644-99
(Red) 5 - 15 830-78-5-002644-00 (Red)
10 - 25 830-69-5-06000-99 (Green) 10 - 25 830-78-5-06000-00
(Green)
20 - 75 830-69-5-06419-95
(Light Blue) 20 - 75 830-78-5-06419-00 (Light Blue)
65 - 150 830-69-5-06418-95 (White) 65 - 150 830-K4-5-06418-00
(White)
140 - 300 H2-5-06417-95
(Maroon) 140 - 210 830-K4-5-06417-00 (Maroon)

Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH [phone]
Fax [phone]
E-mail: [email protected]
[email protected]
Printed in U.S.A. IOM-BQ