Cashco 3381 User Manual download pdf

MODELS 3381 AND 4381

PRESSURE RE DUC ING REGULATORS

SECTION I

Models 3381 and 4381 are pressure reducing regulators used to control downstream (outlet or P

) 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

utili za tion, both units are suitable for liquid, gaseous and steam service (the 4381 can also be used with vari-

ous chemi cals). Refer to Tech ni cal Bul le tins 3381-TB and 4381-TB for speciﬁ c design conditions and selection

rec om men da tions.

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

12-13

1. An inlet block valve should always be installed.

2. If service application is continuous such that

shut down 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 ap-

proxi mately ten pipe diameters downstream, and

within sight.

5. All installations should include a downstream re lief

de vice if the inlet pressure could exceed the pres-

sure rating of any downstream equip ment or the

maximum outlet pressure rating of the unit.

6. Clean the pip ing of all foreign material including

chips, welding scale, oil, grease and dirt before

installing the reg u la tor. Strainers are rec om -

mend ed.

7. In plac ing thread seal ant on pipe ends pri or to

en gage ment, ensure that excess material is re-

moved and not allowed to enter the regulator upon

startup.

8. Flow Direction: Install so the ﬂ ow direction match-

es the arrow cast on the main regulator body.

9. For best performance, install in well drained hori-

zon tal pipe, properly trapped if a steam service

ap pli ca tion.

CAUTION

For welded installations, all internal trim parts, seals and

diaphragm(s) must be removed from reg u la tor body prior

to welding into pipeline. The heat of fusion welding will

dam age non-metallic parts if not re moved. NOTE: This

does not apply to units equipped with extended pipe

nip ples.

CAUTION

Installation of adequate overpressure pro tec tion is recom-

mended to pro tect the reg u la tor from overpressure and

all down stream equip ment from damage in the event of

regulator failure.

CAUTION

Option-1+6 contains single di a phragm con struc tion. In

the event of diaphragm fail ure, the process ﬂ u id will mix

with the load ing ﬂ uid. Please alert your rep re sen ta tive so

an al ter na tive product can be se lect ed.

1 2 3 4 5 6 7 8

Summary of Contents

Page 1 - MODELS 3381 AND 4381

MODELS 3381 AND 4381PRESSURE RE DUC ING REGULATORSSECTION IModels 3381 and 4381 are pressure reducing regulators used to control downstream (outlet or

Page 2 - SECTION IV

IOM-3381/43812III. PRINCIPLE OF OPERATION1. Movement occurs as pressure variations regis-ter on the diaphragm. The registering pressure is the outle

Page 3 - SECTION V

IOM-3381/43813A. General:1. Maintenance procedures hereinafter are based upon re mov al of the regulator unit from the pipeline where in stalled.2.

Page 4

IOM-3381/43814(2), use thread lubricant to minimize po ten tial of seizing threads.D. Special Instructions for Diaphragm Removal:1. If the TFE coated

Page 5 - SECTION VII

IOM-3381/438154. Clean ﬂ at mating surfaces of body (1) to body cap (6) shoulder. Be careful not to scratch either surface.5. Clean debris from with

Page 6 - CAUTION

IOM-3381/438165. Excessive pressure downstream.SECTION VIII4. Sluggish operation.Possible Causes RemediesA. Fluid too viscous. A. Heat ﬂ uid. Contac

Page 7 - MODEL 3381

IOM-3381/43817Option-20, Dome LoadedMODEL 3381 Repair Parts Item No. Description Kit B 1 Body 2 Spring Chamber 3 Pressure Plate 4 Pusher

Page 8 - MODEL 4381

Figure 1:Basic Model 4381 with Metal Seat DesignFigure 2: Option -36 Cryogenic Model 4381 with Metal Seat DesignOption-22 Panel Mounting (Handwheel p

Related models: 4381

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Cashco 3381 User Manual

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Summary of Contents

Related models: 4381

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