Hopkinson Valves IOM Manual

5/22/2018 Hopkinson Valves IOM Manual

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Installation, Operation & Maintenance ManualHopkinsons Swing Check Valve

Page 1 of 7 Weir Valves & Controls UK LtdBritannia House, Huddersfield Rd, Elland. HX5 9JRTel: +44 (0) 1422 282000 Fax: +44 (0) 1422 282100

IOM-P11-R0

Refer to Safety With ValvesBefore Starting Work

1. SAFETY

These instructions contain essential health andsafety requirements concerning the safe use ofthe equipment.

1. For the intended purpose that was specifiedto Hopkinsons, e.g. location, pressure,

temperature, fluid, etc.

2. When installed, operated, maintained, etc. inaccordance with these instructions.

Failure to comply with these points in their entiretyinvolves serious risk.

The manufacturer of this valve and actuator is:

WEIR VALVES & CONTROLS Ltd,Britannia House,Huddersfield Rd,

West Yorkshire,Elland, HX5 9JR. England.

A nameplate is attached to the valve givingdetails in accordance with the valve standard towhich this valve has been manufactured. Itincludes details

of the manufacturing contract and item numberand valve figure number. The nameplate detailsshould be quoted in their entirety in anycorrespondence with Weir valves & Controls,for the enquiry of spare parts or other technicalinformation.

The following warning/instructions are attachedto the valve assembly and must be observedand followed at all times.

SAFETY WARNINGS:Beware of Hot surfaces.Electrically isolate actuator before adjustment ormaintenance to valve.Valve must be depressurised before adjustmentand maintenance.

Please refer to Weir Valves & Controls UK LtdPublications 'SAFETY WITH VALVES' and

'SAFETY WITH ELECTRIC ACTUATORS' forgeneral principles on installation, operation andmaintenance. However, in all cases theseOperating and Maintenance Instructionssupersede any alternative information that maybe given in, for example non-specificcatalogues or the above mentioned generalsafety publications.

At all times the valve must be maintained to asafe condition and any damaged or worn partsmust be replaced with the correct parts suppliedby Weir Valves & Controls Ltd. Users are

strongly recommended to avail themselves ofthe training courses provided by Weir Valves &Controls UK, who also provide on-site and off-site repairs.

We recommend that a record is kept of all workdone to this equipment, including its operatinghistory.

DESCRIPTION

The valve is a swing check valve whosepurpose is to ensure that flow occurs inonly one direction in the pipeline. Forward

Contents PageSafety 1Description 1

Installation 2Commissioning 2Chemical Cleaning of Pipelines 2

Hydraulic Testing 3Preparation for Operation 3Commissioning andOperational Precautions 3

Routine Maintenance 3Valve Overhaul 4Dismantling 4Examination & Courseof Action 4Maintenance of ValveDisc and Seat 5Assembly 4Preventative Maintenance 4Diagrams 5-7


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flow takes place when it moves the discaway from the seat. When flow stops,

gravity causes the disc to fall back onto itsseat and thus prevents any flow in thereverse direction. This operation is entirelyautomatic.

In order for the valve to operate satisfactorilyit must be installed so that gravity assiststhe disc back onto the seat. This entails thisvalve being installed in a horizontal pipelinewith its bonnet being uppermost.(Occasionally a swing check valve may beequipped to work in a vertical pipe with theflow upwards, and where

specified for such duties the valve will bespecially configured for this purpose).

The valve must be installed the correct wayround in the pipeline. The direction of flowis marked with either an arrow on the bodyor by an inlet plate.

The valve disc is fitted with an anti-spinningdevice which prevents the disc fromspinning and the unnecessary wearassociated with this condition. However, thevalve disc has a small amount of movement,thus allowing it to align itself perfectly on theseat.

INSTALLATION

It is the users responsibility to provide a safeworking area, with adequate lighting and anunobstructed access, and that the positionindicator is easily visible.

The valve must be suitably protected againstfalling objects, including rain etc., and must notbe used for any purpose for which it was not

designed e.g. it must not be used for standing on,securing scaffolding, welding earth returns etc.

Before installing make sure all the protection hasbeen removed from the valve and inspect it forany damage which might have occurred duringeither transit or handing. Ensure the pipeworkinto which the valve is to be fixed is square andadequately supported and that it is clean and rustfree with no debris which could affect subsequentvalve operation. Use suitable lifting gear tosupport the valve for installing.

Ensure the valve is positioned the correct way

with respect to both the flow and gravity.

Weld the valve into the pipeline using anapproved procedure.

Once installed, the system must only beoperated so that the valve assembly is notexposed to excess conditions, water hammer,water freezing, corrosion or abuse in any waywhatsoever.

COMMISSIONING

The valve should be thermally insulated -lagged - to protect operators when the valve ishot, and also as an aid to reducing noise and

conserving energy. Such insulation may befitted during or after commissioning providingadequate safety measures are taken to preventhazards from a hot valve.

Commissioning involves testing the valve andthe system that it is in (e.g. hydraulic testing orthe pipe to valve weld, the correct operation ofthe valve etc.), and then equipping the valve forthe start of its operational life (e.g. charging upthe system to the valve). Duringcommissioning it is sometimes necessary tobypass interlocks or safeguards on equipmentin order to simulate meaningful commissioningtrials. Under these circumstances the utmostcare must be exercised. As Hopkinsons Ltdhas not been informed of any procedure whichwill either interfere with this valve in order totest other plant, or to interfere with otherequipment to test this valve, it is theresponsibility of the user to ensure the totalsafety of persons and equipment

The following items may require to be attendedto during commissioning, and it must be

recognised that their mention here is on thestrict understanding that measures will betaken to prevent any risk.

Chemical Cleaning of Pipelines

If chemical cleaning has to be undertaken,ensure the chemicals are compatible withthe materials in the valve. It is importantto ensure that any chemicals used in thisoperation do not soak into the glandpacking where they could promotecorrosion of the valve stem and/or

deterioration of the packing. For thisreason it is recommended that the valve is


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first pressurised with water to saturate the

gland packing. Proceed with the chemicalcleaning and passivation. Then with waterin the valve, pressurise it several times toflush away any chemicals which may havepenetrated the gland packing.

Hydraulic Testing

Test only up to the maximum hydraulic testpressure for the valve rating. Check for leaks,e.g. at valve to pipe connections.

Use corrosion inhibited water for testing.

Note - Shell test pressure is 1.5 times the coldrating pressure stated on the valve nameplate.

Carry out full functional testing and ensureeverything is working correctly.

Preparation for Operation

Note that when the valve enters full and properoperation this may be the first time that the valveis subjected to the most arduous combination ofconditions e.g. flow, temperature (includingambient temperature), pressure, operating loads.It is therefore important that the valve is seen tooperate correctly not only during commissioning,but also when the valve has entered operation.The same is true if the valve should be subject toany changed conditions of operation.

Commissioning and Operational Precautions

In certain circumstances it is possible that the

valve is operated more frequently duringcommissioning than that which occurs duringnormal operation. Disc oscillations produced inthe part open position from low flows, and fromfrequent start-ups produce more wear on thevalve shaft than when the flow is sufficient tokeep the disc in the full open position. Theseflow conditions can also promote chattering incertain circumstances and where this isexperienced the flow should be altered to avoidthis. (If chattering is experienced on full load, it ispossible the valve is oversized for the duty andHopkinsons should be consulted). Routine

maintenance, overhaul, etc. may therefore still benecessary and it should not be assumed that

these can be neglected during commissioning

and early operation.

Internal damage to the valve can also occurduring this period as weld spatter, pipe scale,debris etc. is still finding its way through thesystem pipework. Care should be taken toensure that no damage is done to the valveduring such times.

ROUTINE MAINTENANCE

The valve requires little routine maintenance.

However, the valve should be inspectedexternally, preferably whilst it is operating, tocheck for gland leakage, signs of seat wear orleakage etc., so that timely rectification workcan be arranged.

The frequency of this inspection depends onthe amount of use received by the valve, andthus it is recommended that a suitableinspection interval be taken and this interval isadjusted as necessary in the light of siteexperience.

Take care when approaching a valve,particularly if it is seen to be leaking at thegland.

If the gland has been leaking then de-pressurise the system, and tighten the glandnuts. Glands benefit from early attention tostop leakage, or else a path through the glandpacking will be cut which cannot be remediedby simply re-tightening the gland nuts. Thegland nuts must not be over-tightened! Re-pressurise the system to test for gland leakage.If re-tightening the gland has not made it leak-

tight, then overhaul the valve in accordancewith Sections 5 and 6.

CAUTION: DO NOT OVERTIGHTEN THE

GLAND.

A pressure seal gasket is incorporated toprovide a high integrity body/bonnet joint.

The joint is made by the wedging action of thelid (2) against the joint gasket (9430) which inturn deforms slightly to make a fluid tight sealagainst the joint face in the body (1). Initialjoint contact is made by tightening the jacking


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screw nuts (220) thereby pulling the lid against

the joint gasket.

Fluid pressure, when applied, forces the lidfurther into the tapered bore of the joint gasket,the higher the pressure the greater the intensityof joint load. Outward movement of the joint isprevented by the segmental locking ring (926).

Pressure seal gaskets provide extremelyeffective seals and it is extremely unlikely thatany leakage will be experienced in service.

However, as mentioned above forglands, unlessearly attention to stop gasket leakage is taken, a

path will be cut through the gasket which cannotbe rectified by tightening the jacking screws. Thejacking screws must not be over-tightened! Incase of leakage, dismantle the valve inaccordance with section 5.

VALVE OVERHAUL

Overhaul the valve only when it is safe to do so.Obtain the correct spare parts prior to dismantlingthe valve. Do not attempt to reuse gland packingmaterial.Care must be taken not damage to the spindle or

stuffing box when removing old packing material.Clean and inspect all parts and replace anydamaged components.

DISMANTLING

WARNING: Before carrying out any dismantlingwork on the valve, make sure there is NOpressure in the pipeline and that the valve is safeto work on.

DISMANTLING PROCEDURE

1. Mark relative axial positions of cover (200) andbody (1) for reference when

reassembling after overhaul.2. Remove the jacking screw nuts (220) and

distance pieces (201) then the cover (200>

3. In order to break the lid seal, strike the bonnet(2) with a hammer using a piece of

wood, so as not to damage the bonnet until itdrops.

4. Remove segmental locking ring (926), holdingring (424) and joint gasket (430).

Note: If the segmental locking ring is not loose,

tap lightly with a hammer and softmetal drift. Note the master segment whichshould be removed first, has two parallelsides.

5. Lift out bonnet (2).

6. Remove plug gland stud nuts (522), plug gland(12), packings (921) and unscrew

plug (427).7.Support the weight of the valve head assembly.Withdraw valve arm spindle (139)and remove valve arm (185) and valve disc (35)

from body (1).

8.If new bushes (38) (45) are to be fitted thesecan be removed from the body.Body bush (38) is provided with bush removalthread for this purpose. When new bushesare fitted, ensure that a serviceable bush thread

is provided.

Examination and Course of Action

Visual inspection of the joint faces on the body,bonnet and gasket will reveal any

major defects immediately, such as steamerosion marks etc.

If in the unlikely event that the valve has beenleaking from the pressure seal joint prior tobeing taken out of service, and the following upof the adjusting screw nuts has provedunsuccessful, then it may be found that thetrouble is due to damage of the joint gasket orless likely to either the bonnet joint faces or thebody joint faces. Unless leakage has beenallowed to take place over a prolonged period

the damage to these faces will be slight and inmost cases can be corrected by any polishingwith fine emery cloth.

The bonnet may be machined in a lathe if it isbadly damaged, provided that the correct jointface angle be maintained. This accuracy isessential for the correct sealing of the pressureseal joint. The face must be polished using FFfine emery cloth or equivalent.

Examination and Course of Action

Thoroughly clean all joint faces. Do notlubricate them in any way, as carbonisation of


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grease or oil could cause serious leakage bypreventing correct contact.

MAINTENANCE OF VALVE HEAD AND SEATFACE

It is not normally necessary to dismantle the valvedisc assembly as the face may be lapped whilstthe disc is still on the arm. Ensure the disc has asmall amount of freedom on the arm. If the valvedisc assembly is dismantled, we recommend thatnew stop setscrews and a new locking plate befitted.

The work entailed in the renovation of the valvehead and seat face should be under the control ofa skilled mechanic, preferably one specialising inthis type of maintenance. The valve head and seatmust be lapped independently. No satisfactoryresult can be obtained by attempting to lap thevalve head directly on to its seat. Suitable lappingplates for the seat can be supplied by us:alternatively they can be readily manufactured incast iron.

ASSEMBLY PROCEDURE

1.Check that body bushes are in position.

2.Replace valve arm (185) and valve head (35) inbody, position in place and supportits weight.

3.Fit valve arm spindle (139). Refit plug (427),leaving 1mm clearance with the valvearm spindle. Fit new packing (921) with plug gland(12) and plug gland stud nuts(522). Remove material used for supporting the

valve head.

4.Do not overtighten the body gland stud nuts(522). Make sure the valve head assemblymoves freely before refitting the bonnet.

5.Place the bonnet (2) in position, resting on theshoulder in the valve body.

6.Carefully position the new joint gasket (430) andholding ring (424) ensuring they aresquare in the bore.

7.Replace the segmental locking ring (926), inorder, with the master segment last.

8.Replace cover (200), distance pieces (201) andstud nuts (220). Check location of cover.

9.Tighten the jacking screw nuts (220)systematically to ensure that the joint gasket(430),locking ring (926), holding ring (424) and bonnet(2) are evenly and squarely pulled upto the load bearing shoulder in the body.

Note: This part of the assembly procedure is byfar the most important as damage to the

gasket, or faces, at this point can undo allprevious work.

10. Test.

CAUTION: Do not overtighten gland nuts orjacking screw nuts.

PREVENTATIVE MAINTENANCE

Regularly inspect valves for signs of glandleakage. The gland packing can be tightened to

prevent leakage but if a leak has persisted forsome time it will have blown out some of thepacking material and thus simply tightening thegland will not prevent the leakage. In additionthe lack of support given to the stem by thegland packing may allow for the stem to comeinto contact with the metal gland parts.

Caution: Only undertake preventativemaintenance when it is safe to do so.Do not over tighten gland nuts in an attempt tostop gland leaks. If the leakage cannot becontrolled, then overhaul the gland at the

earliest opportunity.


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Hopkinson Valves IOM Manual

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