cashco 3381 Instruction manual

MODELS 3381 AND 4381
PRESSURE REDUCING REGULATORS
SECTION I
Models 3381 and 4381 are pressure reducing regulators used to control downstream (outlet or P2) pressure.
Sizes are 1/4" and 3/8" (DN8 and DN10) for the 3381. Sizes for the 4381 are 1/4", 3/8", and 1/2" (DN8, DN10,
and DN15). The 3381 is a bronze bodied unit; the 4381 incorporates a stainless steel body. With proper trim
utilization, both units are suitable for liquid, gaseous and steam service (the 4381 can also be used with various
chemicals). Refer to Technical Bulletins 3381-TB and 4381-TB for specific design conditions and selection
recommendations.
The instructions in this manual will apply to both models, unless otherwise stated.
I. DESCRIPTION AND SCOPE
II. INSTALLATION
SECTION II
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-3381/4381
06-17
1. An inlet block valve should always be installed.
2. If service application is continuous such that
shutdown is not readily accomplished, it is rec-
ommended 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 outlet pressure gauge should be located
approximately ten pipe diameters downstream,
and within sight.
5. All installations should include a downstream
relief device if the inlet pressure could exceed the
pressure rating of any downstream equipment or
the maximum outlet pressure rating of the unit.
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
engagement, 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 main regulator
body.
9. For best performance, install in well drained
horizontal pipe, properly trapped if a steam
service application.
CAUTION
For welded installations, all internal trim parts, seals and
diaphragm(s) must be removed from regulator body prior
to welding into pipeline. The heat of fusion welding will
damage non-metallic parts if not removed. NOTE: This
does not apply to units equipped with extended pipe
nipples.
CAUTION
Installation of adequate overpressure protection is
recommended to protect the regulator from overpressure
and all downstream equipment from damage in the event
of regulator failure.
CAUTION
Option-1+6 contains single diaphragm construction. In
the event of diaphragm failure, the process fluid will mix
with the loading fluid. Please alert your representative so
an alternative product can be selected.
ISO Registered Company

IOM-3381/43812
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is
the outlet, P2, or downstream pressure. The
range spring opposes diaphragm movement. As
SECTION III
IV. STARTUP
SECTION IV
5. Slowly open the inlet (upstream) block valve
observing the outlet (downstream) pressure
gauge. Determine if the regulator is flowing. If
not, slowly rotate the regulator adjusting screw
clockwise (CW) until flow begins.
6. Continue to slowly open the inlet (upstream) block
valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream
piping system isn't pressurized. If the outlet
(downstream) pressure exceeds the desired
pressure, close the block valve and go to Step 2,
then return to Step 4.
8. When flow is established steady enough that the
outlet (downstream) block valve is fully open,
begin to slowly close the bypass valve if installed.
9. Develop system flow to a level near its expected
normal rate, and reset the regulator set point by
turning the adjusting screw CW to increase outlet
pressure, or CCW to reduce outlet pressure.
10. Reduce system flow to a minimum level and
observe set point. Outlet pressure will rise from
the set point of Step 9. The maximum rise in
outlet pressure on decreasing flow should not
exceed the stated upper limit of the range spring
by greater than 10%; i.e. 20-80 psig (1.38-5.52
Barg) range spring. (Example: at low flow the
outlet pressure should not exceed 88 psig (6.07
barg), if it does, consult factory).
CAUTION
outlet pressure drops, the range spring pushes
the diaphragm down, opening the port; as outlet
pressure increases, the diaphragm pushes up
and the port opening closes.
2. A complete diaphragm failure will cause the
regulator to fail open.
10 A. Basic Regulator - (Refer to Figure 1, Model 3381
or 4381): Regulator may be rotated around the
pipe axis 360°. Recommended position is with
spring chamber vertical upwards. Orient such
that the spring chamber vent hole does not collect
rainwater.
10B. Cryogenic Regulator - Options 3381-5 and 4381-
36 (Refer to Figure 2, Model 3381 or 4381):
a. Recommended installation is with spring
chamber hanging directly below the body in a
vertical downwards orientation. Allows water
to drain; etc.
b. Recommend inert purge gas be supplied to
spring chamber through vent hole and be
discharged out drain hole.
11. Regulators are not to be buried underground.
12. For insulated piping systems, recommendation is
to not insulate regulator.
CAUTION
The maximum outlet pressure is listed on the nameplate
as the upper range spring pressure level, and is the
recommended "upper operative limit" for the sensing
diaphragm (See Section IV. Startup, Step 7). Higher press-
ures could damage the diaphragm. (Field hydrostatic
tests frequently destroy diaphragms. DO NOT HYDRO-
STATIC TEST THROUGH AN INSTALLED UNIT; ISOLATE
FROM TEST.)
1. Start with the block valves closed. A bypass
valve may be used to maintain outlet pressure
in the downstream system without changing the
following steps.
2. Relax the range spring by turning the adjusting
screw counter clockwise (CCW) a minimum of
three (3) full revolutions. This reduces the outlet
(downstream) pressure set point.
3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
expansion of the piping. Ensure proper steam
trap operation if installed. Closely monitor outlet
(downstream) 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.
4. Crack open the outlet (downstream) block valve.

IOM-3381/4381 3
A. General:
1. Maintenance procedures hereinafter are
based upon removal of the regulator unit from
the pipeline where installed.
2. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
nonreusable parts, i.e. gaskets, etc.
3. Refer to Figure 1, Model 3381 or 4381 for the
basic regulator and Figure 2, Model 3381 or
4381 for the cryogenic regulator. Blow-ups of
options and the composition seat trim are on
either drawing.
B. Diaphragm Replacement - Model 3381:
VI. MAINTENANCE
SECTION VI
3. Loosen spring chamber (2) by placing wrench
on “flats” and rotating CCW making sure not
to use the flat where the vent hole is located.
4. Remove spring chamber (2), range spring
(17) and spring button (5).
5. Remove the diaphragm subassembly
consisting of the pressure plate nut (10), lock
washer (9), pressure plate (3), diaphragm
(13), pusher plate seal (15) and pusher
plate (4). NOTE: Refer to the quantity of
diaphragms (13) incorporated per the bill
of materials listing. Depending on outlet
pressure level, multiple metal diaphragms
may be “stacked”.
6. Loosen pusher plate nut (10) and separate
all parts (3, 4, 9, 13 & 15) of the diaphragm
subassembly.
7. Inspect pressure plate (3) to ensure no
deformation due to over-pressurization. If
deformed, replace.
8. Remove diaphragm gasket (14). (If a
composition diaphragm is used there is no
diaphragm gasket (14).
9. Clean body (1) and diaphragm flange. Do not
scratch diaphragm gasket seating surface.
NOTE: On regulators originally supplied as
“oxygen clean”, Option s 3381-5 & -55, 4381-
36 & -55, maintenance must include a level
of cleanliness equal to Cashco's cleaning
Diaphragm Subassembly
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.
2. If the regulator and system are to both be shut
down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if regulator removal is required.
SECTION V
CAUTION
Do not walk away and leave a bypassed regulator
unattended.
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
personal injury.
WARNING
SPRING UNDER COMPRESSION. Prior to removing the
spring chamber, relieve spring compression by backing
out the adjusting screw. Failure to do so may result in
flying parts that could cause personal injury.
CAUTION
To prevent damage to body, use soft jaws when securing
the body in a vise. Position so that vise closes over the
inlet and the outlet connections.
1. Securely body (1) in a vise with the spring
chamber (2) oriented upwards.
2. Relax range spring (17) by turning adjusting
screw (8) CCW until removed from spring
chamber (2).

IOM-3381/43814
2. For SST body (1) and SST spring chamber
(2), use thread lubricant to minimize potential
of seizing threads.
D. Special Instructions for Diaphragm Removal:
1. If the TFE coated diaphragm (13) is utilized on
the Model 4381, the TFE coating is the wetted
side of the diaphragm.
2. If the Option-2 is utilized, the adjusting screw
(8) and locknut (11) are replaced with a
handwheel (18) and lock nut (11). With the
Option-22 panel mounting w/handwheel,
the adjusting screw (8) and lock nut (11) are
replaced with a handwheel (18), lock nut (11)
and a panel mounting nut (19).
3. If the Option-1+6 is utilized with metal
diaphragms, there will be one diaphragm
gasket (14) on top of and one below the
diaphragm(s).
11. Formetaldiaphragm(s)(13),placediaphragm
gasket (14) into body (1) recess (none
required for composition diaphragm). Set
diaphragm subassembly into the body.
12. Place the range spring (17) over the pusher
plate nut (10) of the diaphragm subassembly.
13. Place multipurpose, high temperature grease
into depression of spring button (5) where
adjusting screw (8) makes contact. Set spring
button (5) onto range spring (17); ensure
spring button (5) is laying flat on top of spring.
14. Rotate the spring chamber (2) CW by hand
into the threaded portion of the body (1)
ensuring not to cross thread. Continue
rotating CW into the body and tighten
approximately 1/4 turn past initial contact with
the diaphragm. Use caution when tightening
the spring chamber, contact with the wrench
on the vent hole boss may damage it.
15. Reinstall adjusting screw (8) with locknut (11)
into the spring chamber (2).
16. Pressurize with air and spray liquid leak
detector to test around body (1) and spring
chamber (2) for leakage. Ensure that an outlet
pressure is maintained during this leak test
of at least mid-range spring level; i.e. 20-80
psig (1.4-5.5 Barg) range spring, 50 psig
(3.4 Barg) test pressure minimum.
C. Diaphragm Replacement - Model 4381:
1. Procedures are the same as Model 3381.
2. Loosen and remove body cap.
3. Remove piston spring (7), and piston (16).
Note that the seat and piston guide are
integral parts of the body (1) casting. Inspect
integral seat and guide for excessive wear,
especially at seat surfaces. Replace if worn,
nicked or depressed. If integral seat is nicked,
use seat lapping compound to remove.
Valves equipped with Opt-4 Stabilizer will
have the u-cup stabilizer seal (30) removed
when the piston (16) is removed from body
(1). Remove stabilizer seal (30), if installed.
NOTE: When piston (16) assemblies are
used with composition seats, Cashco, Inc.
does not recommend attempting to remove
the composition seat. If composition seat is
damaged, replace entire piston assembly.
standard #S-1134. For regulators originally
supplied as “cleaned for Pharmaceutical
and Food applications” Options 4381-37
and 4381-37S, maintenance must include a
level of cleanliness equal to Cashco cleaning
standard #S-1576. Contact factory for details.
10. Reassemble diaphragm subassembly by
placing pusher plate seal (15) over threaded
post of pusher plate (4), placing diaphragm(s)
(13) and pressure plate (3) over the threaded
post. Assure the pressure plate (3) is
placed with curved outer rim down next to
the diaphragm (13) surface. Place a thread
sealant compound on the threads of the
pusher plate post (4) prior to tightening the
pusher plate nut (10) to the following torque
values:
Sizes Diaphragm Torque
In-lbs (N-m)
ALL Metal 60 (6.8)
Composition 15 (1.7)
CAUTION
To prevent damage to the body, use soft jaws when
securing body in a vise. Position body so that vise closes
over the inlet and the outlet connections.
CAUTION
Option-1+6 contains single diaphragm construction. In
the event of diaphragm failure, the process fluid will mix
with the loading fluid. Please alert your representative so
an alternative product can be selected.
E. Trim Replacement:
1. Secure body (1) in a vise with the body cap
(6) oriented up and the spring chamber (2)
downwards.

IOM-3381/4381 5
4. Clean flat mating surfaces of body (1) to body
cap (6) shoulder. Be careful not to scratch
either surface.
5. Clean debris from within the body (1) cavity.
Parts to be reused should be cleaned
according to owner's procedures. NOTE:
On regulators originally supplied as “oxygen
clean”, Options 3381-5 & -55, 4381-36
& 55 maintenance must include a level of
cleanliness equal to Cashco's cleaning stan-
dard #S-1134. For regulators originally
supplied as “cleaned for Pharmaceutical
and Food applications” Options 4381-37
and 4381-37S, maintenance must include a
level of cleanliness equal to Cashco cleaning
standard #S-1576. Contact factory for
details.
6. If supplied with Opt-4 Stabilizer, install new
stabilizer seal (30) properly oriented onto
piston (16).
7. Slide the piston (16), including stabilizer seal
(30) if supplied, slowly into the body cavity.
Use thumbs to ease stabilizer seal(30) into
the body cavity.
8. Place piston spring (7) over spring hub of the
piston (16).
9. Apply pipe thread sealant to the body cap (6)
threads. Screw body cap (6) into body (1).
When body cap is fully down against body
(1) at the body cap (6) shoulder, impact the
body cap (6) into the body (1). NOTE: When
unit is put into service and pressurized, these
two parts seal metal-to-metal with no gasket.
10. Bench test unit for suitable operation. NOTE:
Regulators are not tight shutoff devices.
Even if pressure builds up beyond set point,
a regulator may or may not develop bubble
tight shutoff. In general, tighter shutoff can
be expected with composition seat.
11. Pressurize with air and spray liquid leak
detector to test around body cap (6) and body
(1) for leakage. Test pressure should be a
minimum of 100 psig (6.9 Barg) at the inlet.
2. Regulator can't pass sufficient flow.
VII. TROUBLE SHOOTING GUIDE
1. Erratic operation; chattering.
SECTION VII
Possible Causes Remedies
A. Oversized regulator; inadequate rangeability. A1.
A2.
A3.
A4.
A5.
Check actual flow conditions, re-size regulator for minimum and maximum flow.
Increase flow rate.
Decrease regulator pressure drop; decrease inlet pressure by placing a throttling orifice
in inlet piping union.
Install next step higher range spring. Contact factory.
Before replacing regulator, contact factory.
B. Worn piston; inadequate guiding. B. Replace trim ( possible body replacement).
C. Weakened/broken piston spring. C. Replace piston spring. Determine if corrosion is causing the failure.
Possible Causes Remedies
A. Regulator undersized. A1.
A2.
Confirm by opening bypass valve together with regulator.
Check actual flow conditions, re-size regulator; if regulator has inadequate capacity,
replace with larger unit.
B. Incorrect range spring (screwing in CW of ad-
justing screw does not allow bringing pressure
level up to proper level).
B. Replace range spring with proper higher range. Contact factory.
C. Too much droop. C1.
C2.
Review droop expected.
Contact factory.
3. Leakage through the spring chamber vent hole.
Possible Causes Remedies
A. Normal-life diaphragm failure. A. Replace diaphragm.
B. Abnormal short-life diaphragm failure. B1.
B2.
B3.
B4.
Can be caused by excessive chattering. See No. 1. to remedy chatter.
Can be caused by corrosive action. Consider alternate diaphragm material.
For composition diaphragms, ensure not subjecting to over-temperature conditions.
Downstream (outlet) pressure buildup occurring that overstresses diaphragms. Relo-
cate regulator or protect with safety relief valve.

IOM-3381/43816
5. Excessive pressure downstream.
SECTION VIII
4. Sluggish operation.
Possible Causes Remedies
A. Fluid too viscous. A. Heat fluid. Contact factory.
Possible Causes Remedies
A. Regulator not closing tightly. A. Inspect the seating. Clean and lap metal seat surfaces; replace if lapping does
not remedy. If composition seats are depressed, nicked or embedded with debris,
replace trim.
B. Downstream block. B. Check system; isolate (block) flow at regulator inlet - not outlet. Relocate regula-
tor if necessary.
C. No pressure relief protection. C. Install safety relief valve, or rupture disc.
D. Restricted diaphragm movement. D. 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
regulator.
NEW REPLACEMENT UNIT:
Contact your local Cashco, Inc., Sales Representative
with the Serial Number and Product code. With this
information they can provide a quotation for a new unit
including a complete description, price and availability.
–7–
VIII. ORDERING INFORMATION
NEW REPLACEMENT UNIT vs PARTS "KIT" FOR FIELD REPAIR
To obtain a quotation or place an order, please retrieve the Serial Number and Product Code that was stamped on the metal
name plate and attached to the unit. This information can also be found on the Bill of Material ("BOM"), a parts list that was
provided when unit was originally shipped. (Serial Number typically 6 digits). Product Code typical format as follows: (last
digit is alpha character that reflects revision level for the product).
PARTS "KIT" for FIELD REPAIR:
Contact your local Cashco, Inc., Sales Representative
with the Serial Number and Product code. Identify the
parts and the quantity required to repair the unit from
the ("BOM") sheet that was provided when unit was
originally shipped.
NOTE: Those part numbers that have a quantity indicated
under "Spare Parts" in column "A” reflect minimum
parts required for inspection and rebuild, - "Soft Goods
Kit". Those in column “B” include minimum trim
replacement parts needed plus those "Soft Goods"
parts from column "A".
If the "BOM" is not available, refer to the cross-sectional
drawings included in this manual for part identification
and selection.
A Local Sales Representative will provide quotation for
appropriate Kit Number, Price and Availability.
CAUTION
Do not attempt to alter the original construction of any
unit without assistance and approval from the factory.
All purposed changes will require a new name plate
with appropriate ratings and new product code to
accommodate the recommended part(s) changes.
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be
construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to
modify or improve the designs or specifications of such product at any time without notice.
Cashco, Inc. does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any
Cashco, Inc. product remains solely with the purchaser.

IOM-3381/4381 7
Option-20, Dome Loaded
MODEL 3381
Repair Parts
Item No. Description Kit B
1 Body
2 Spring Chamber
3 Pressure Plate
4 Pusher Plate
5 Spring Button
6 Body Cap
7 Piston Spring -------- ‡‡
8 Adjusting Screw
9 Lock Washer
10 Pressure Plate Nut
11 Adjusting Screw Locknut
12 Nameplate
13 Diaphragm ----------- ‡‡
14 Diaphragm Gasket(s)‡‡
15 Pusher Plate Gasket ‡‡
16 Piston ----------------- ‡‡
17 Range Spring
18 Handwheel
19 Mounting Nut
Figure 1:
Basic Model 3381 with Metal Seat Design
Composition Seat Design
(NOTE: Mount in Horizontal line with
Adjusting Screw down as shown.)
Figure 2:
Option-5 Cryogenic Model 3381, Metal Seat Design
Option-22 Panel Mounting
(Handwheel portion is same as Option-2 Handwheel)
Spring Chamber Thread 3/4"-16 UNF-2A

IOM-3381/43818
Figure 1:
Basic Model 4381 with Metal Seat Design
Figure 2:
Option -36 Cryogenic Model 4381 with Metal Seat Design
Option-22 Panel Mounting
(Handwheel portion is same as Option-2 Handwheel).
Option-22 NOT available with Option-80.
Spring Chamber Thread 3/4"-16 UNF-2A
Option-80, High Pressure
Spring Chamber Construction
Repair Parts
Item No. Description Kit B
1 Body
2 Spring Chamber
3 Pressure Plate
4 Pusher Plate
5 Spring Button
6 Body Cap
7 Piston Spring ---------------- ‡‡
8 Adjusting Screw
9 Lock Washer
10 Pressure Plate Nut
11 Adjusting Screw Locknut
12 Nameplate
13 Diaphragm ------------------- ‡‡
14 Diaphragm Gasket --------- ‡‡
15 Pusher Plate Seal ---------- ‡‡
16 Piston ------------------------- ‡‡
17 Range Spring
18 Handwheel
19 Mounting Nut
21 Thrust Bearing
22 Upper Bearing
23 Lower Bearing
30 U-Cup ------------------------- ‡‡
(NOTE: Mount in Horizontal line with
Adjusting Screw down as shown.)
Composition Seat
with Option -4 Stabilizer
MODEL 4381

IOM-3381/4381 9
ATEX 94/9/EC: Explosive Atmospheres and Cashco Inc. Regulators
These valves satisfy the safety conditions according to EN 13463-1 and EN 13463-5 for equipment group IIG 2 c.
Caution: Because the actual maximum temperature depends not on the equipment itself, but upon the fluid temperature, a
single temperature class or temperature cannot be marked by the manufacturer.
Specific Precaution to Installer: Electrical grounding of valve must occur to minimize risk of effective electrical discharges.
Specific Precaution to Installer: Atmosphere vent holes should be plugged to further minimize the risk of explosion.
Specific Precaution to Maintenance: The Valve Body/ Housing must be regularly cleaned to prevent buildup of dust deposits.
Specific Precaution to Maintenance: Conduct periodic Continuity Check between Valve Body/ Housing and Tank to minimize
risk of electrical discharges.
Attention: When repairing or altering explosion-protected equipment, national regulations must be adhered to. For maintenance
and repairs involving parts, use only manufacturer's original parts.
ATEX requires that all components and equipment be evaluated. Cashco pressure regulators are considered components.
Based on the ATEX Directive, Cashco considers the location where the pressure regulators are installed to be classified
Equipment-group II, Category 3 because flammable gases would only be present for a short period of time in the event of a leak.
It is possible that the location could be classified Equipment-group II, Category 2 if a leak is likely to occur. Please note that the
system owner, not Cashco, is responsible for determining the classification of a particular installation.
Product Assessment
Cashco performed a conformity assessment and risk analysis of its pressure regulator and control valve models and their
common options, with respect to the Essential Health and Safety Requirements in Annex II of the ATEX directive. The details
of the assessment in terms of the individual Essential Health and Safety Requirements, are listed in Table 1. Table 2 lists all of
the models and options that were evaluated and along with their evaluation.
Models and options not listed in Table 2 should be assumed to not have been evaluated and therefore should not be selected
for use in a potentially explosive environment until they have been evaluated.
Standard default options for each listed model were evaluated even if they were not explicitly listed as a separate option in the
table. Not all options listed in the tables are available to all models listed in the tables. Individual TB’s must be referenced for
actual options.
When specifying a regulator that is to be used in a potentially explosive environment one must review the evaluations in Table 1
and 2 for the specific model and each and every option that is being specified, in order to determine the complete assessment
for the unit.
A summary of the models and options found to have an impact on ATEX assessment due to potential ignition sources or other
concerns from the ATEX Essential Health and Safety Requirements, are listed below.
1. The plastic knob used as standard on some models, (P1, P2, P3, P4, P5, P7, 3381, 4381, 1171, and 2171) is a
potential ignition source due to static electricity. To demonstrate otherwise, the knob must be tested to determine
if a transferred charge is below the acceptable values in IEC 60079-0 Section 26.14 (See items 25, 27, and 28 in
Appendix A). Until the plastic knob has been shown to be acceptable, then either the metal knob option, or a preset
outlet pressure option is required to eliminate this ignition source (See items 45 and 64 in Tables).
2. The pressure gauges offered as options on a few of the regulator models (DA’s, P1-7, D, 764, 521), use a plastic
polycarbonate window that is a potential ignition source due to static electricity. To demonstrate that the gauges are
not a potential source of ignition, the gauges would need to be tested to determine if a transferred charge is below
NOTICE
Only for Product Codes wherein hazard
category ATEX has been selected.

IOM-3381/438110
indicating the gauge is compliant with the ATEX Directive (See items 26, 27, and 28 in Appendix A). Until compliance
is determined, regulators should not be ordered with pressure gauges for use in potentially explosive environments.
3. Tied diaphragm regulators with outlet ranges greater than 100 psig should be preset to minimize the risk that improper
operation might lead to an outboard leak and a potentially explosive atmosphere (See item 6 in Table 1).
4. Regulators must be ordered with the non-relieving option (instead of the self-relieving option) if the process gas they are
to be used with is hazardous (flammable, toxic, etc.). The self-relieving option vents process gas through the regulator
cap directly into the atmosphere while the non-relieving option does not. Using regulator with the self- relieving option
in a flammable gas system could create an explosive atmosphere in the vicinity of the regulator.
5. Regulators with customer supplied parts are to be assumed to not have been evaluated with regard to ATEX and thus
are not to be used in a potentially explosive environment unless a documented evaluation for the specific customer
supplied parts in question has been made. Refer to Table 1 for all models and options that have been evaluated.
Product Usage
A summary of ATEX related usage issues that were found in the assessment are listed below.
1. Pressure regulators and control valves must be grounded (earthed) to prevent static charge build-up due to the flowing
media. The regulator can be grounded through any mounting holes on the body with metal to metal contact or the
system piping can be grounded and electrical continuity verified through the body metal seal connections. Grounding
of the regulator should follow the same requirements for the piping system. Also see item 30 in Table 1.
2. The system designer and users must take precautions to prevent rapid system pressurization which may raise surface
temperatures of system components and tubing due to adiabatic compression of the system gas.
3. Heating systems installed by the user could possibly increase the surface temperature and must be evaluated by the
user for compliance with the ATEX Directive. User installation of heating systems applied to the regulator body or
system piping that affects the surface temperature of the pressure regulator is outside the scope of this declaration and
is the responsibility of the user.
4. The Joule-Thomson effect may cause process gases to rise in temperature as they expand going through a regulator.
This could raise the external surface temperature of the regulator body and downstream piping creating a potential
source of ignition. Whether the Joule-Thomson effect leads to heating or cooling of the process gas depends on
the process gas and the inlet and outlet pressures. The system designer is responsible for determining whether the
process gas temperature may rise under any operating conditions. If a process gas temperature rise is possible under
operating conditions, then the system designer must investigate whether the regulator body and downstream piping
may increase in temperature enough to create a potential source of ignition.
The process gas expansion is typically modeled as a constant enthalpy throttling process for determining the temperature change.
A Mollier diagram (Pressure – Enthalpy diagram with constant temperature, density, & entropy contours) or a Temperature –
Entropy diagram with constant enthalpy lines, for the process gas, can be used to determine the temperature change. Helium
and hydrogen are two gases that typically increase in temperature when expanding across a regulator. Other gases may
increase in temperature at sufficiently high pressures.
Product Declaration
If the above issues are addressed by selecting options that do not have potential sources of ignition, avoiding options that
have not been assessed, and by taking the proper usage issue precautions, then Cashco regulators can be considered to be a
mechanical device that does not have its own source of ignition and thus falls outside the scope of the ATEX directive.
Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH [phone]
Fax. # [phone]
www.cashco.com
email: [email protected]
Printed in U.S.A. IOM-3381/4381
Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH [phone]
Fax. No.
www.cashco.com
email: [email protected]
Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH [phone]
Fax. No. [phone]
www.cashco.com
email: [email protected]