operating manual needle version1.pdf

7/29/2019 operating manual needle version1.pdf

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Via Galvani, 6 - 38015 Lavis - TN - Tel. 0461- 24 83 11 - Fax 0461 - 24 70 24

INSTRUCTIONS COVERINGSTORAGE, COMMISIONING

ANDMAINTENANCE

OFNEEDLE VALVES




HYDRAULIC VALVE

If the valves have to be stored for a long period of time ina warehouse before being mounted in the hydraulicsystem, following rules have to be followed:

Handling

The handling of the valve has to be made with care, inorder to avoid any shock, even accidental, which coulddamage it. In particular any lift of the valve should becarried out in paying attention that the chain, cable or ropeused for that specific operation is not fixed or does nottouch the shafts, the operator or its respective handwheel.Ends of the valve body or its respective flanges (flangehole) should be used for this operation.It is absolutely forbidden to use the eventual hook (s) of the actuator to lift the valve.The storage area should be located as far as possiblefrom any working area.

Storage

Close the inlet and outlet of the valve with flange covers, inorder to protect the internal parts of the valve and inparticular the seat.• The valves must be stored in a location offering a good

protection against the sun, the rain and all other atmospheric elements. It must be avoid that the valveseat comes in contact with earth or dust. In case of open storage condition, the valve has to be wrappedwith a cellophane or plastic sheet, if possible of darkcolour.

• The valves should be kept generally in their closedposition.

• The rubber components of the valves (especially theseat ring of disk, for example for butterfly valves or resilient seated gate valves) have to be protectedcarefully against the light and in particular the sunlight,in order to avoid any structural alteration of the rubber which could change the specific properties of thevalves.

Inspection before installation

Before mounting the valve in the system, it should becontrolled that no earth or dust or foreign matter arecontained in the valve body and in particular that the valveseat is clean. Every fixing screw (mounted inside or outside the valve) should be checked and any loosenedscrew should be tightened.One complete cycle of opening/closing of the valve has tobe made in order to check that all components ensuringthis specific operations are working correctly.

ACCESSORIES

• Seat rings of disk Normally the seat ring of the disk is made with a rubber quality which is sensitive to the sunlight. Therefore it isusual to store such rubber part in an area protected from

the sunlight, in order to avoid its deterioration. If suchconditions are not available, rubber parts should be then atleast protected by cellophane or plastic sheets of darkcolour.

• Bolt, nut, screwThe requested flange bolting is normally packed in a sackor a box equipped with a tag indicating the number and thetype of the packed bolts. It is absolutely necessary to keepthem in the original condition of delivery, avoiding to putthem in contact with material which could damage them.Generally the bolting is slightly lubricated before delivery;any contact with earth or dust could, in extreme case,

damage the threads and prevents its future mounting.

Electric, hydraulic, pneumatic operator For this particular type of accessory, which is alreadymounted on the valve at the time of the reception in theworks, it is necessary to pay attention that nobody, at theexception of the specialist or authorized people, isattempting to repair or rework it, which would take out anywarranty covering these specific components.It is very important to check that the threaded orificespermitting the future electric/hydraulic/pneumaticconnections are always well protected with the originaltaps until they will be used for the final assembly. This will

insure that no earth, dust, humidity or any other foreignparticle will damage the internal parts (gears, electricalcoils, pistons, cylinders, seats, etc.).When the electrical wiring is not made immediately after the mechanical mounting of the valve in the pipe system,the installator/contractor will take the necessary measureto protect correctly and thoroughly the actuator against anyatmospheric degradation and the built-up of condensation.Furthermore it is necessary to check periodically duringthis particular period of time the status of internalcomponents, by removing, with this purpose, the covers of the operative unit and of the reduction unit, protecting withsilicone or Vaseline the respective cover gaskets when

remounting them.

MOUNTING OF HYDRAULIC VALVES

The mounting of any valve in a pipe should evidently bemade without any water in the system; further theinstallator should be absolutely informed about thepreferential direction of flow in the pipe, in order to mountthe valve according its respective direction of work,indicated by a casted arrow in the valve body. Themounting recommendations given below are the basis of acorrect and handy assembly of the valve in the system:

• The pipeline should be as free as possible fromwelding, scraps, of mounting accessories, of earth,etc. The cleanest the pipe is kept during its




installation, the less trouble (which can be sometimevery bad) the commissioning of the system with itsrespective initial flushing will produce.

• If the transported fluid in the system is contains a lot

of foreign solid particles, it is solid recommended toinstall in the upstream side of the valve one in-linestrainer.

• Both pipe flanges, which are connected to the valve,should be located perfectly in the centerline of the pipeand absolutely parallel. If no dismantling joint isforeseen in the mounting procedure of the valve, thedistance between the two pipe flanges should than beabsolutely matching the overall length given by thevalve manufacturer including in addition twice thethickness of the flange gasket. Any longer distancebetween the two pipe flanges (even of some mm) can

produce during the tightening of the flange bolts/nutsvery high yield stress on the valve, which, if made incast iron can break.

• A sufficient space should be provided around thevalve to permit its usual operation, as well as anyeventual setting or future maintenance work.

• It is usually foreseen to include in the mountingprocedure of a valve (at least from the size ND 150) adismantling joint. The device, including two sections of concentric flanged pipes, moving one into the other, isnormally mounted in the downstream side of the valve

(considering the preferential direction of the flow of thepipe); it is avoiding, through its adjustable length rangeof 20 mm to 60 mm (depending the nominaldiameter), to provide an accurate mounting lengthbetween the pipe flanges (see above) and takes careof any eventual length modification due to the weldingof a flange (for example). If used at the downstreamside of a butterfly valve, it allows, when removed off the pipe, to check the internal wear level in workingcondition and/or to change the seat ring of the valve,without taking this last one out of the pipe.

• The valve has to be mounted in the pipe in such a way

that the casted arrow in its body is matching thepreferential direction of flow of the system. Theabsence of any directional arrow on the body meansthat the valve can be mounted without restriction inany direction of flow. It has to be noted that only themounting of a butterfly valve according to its arrow of preferential direction of flow will allow any futurereplacement of its seat ring (at the downstream side of the valve) without taking the valve out of the pipe.

• Hydraulic valve (s), without particular prescription, canbe mounted in any position in relation with the center line of the pipe (horizontal, vertical, inclined). The

fiability of any hydraulic valve is usually depending of the service conditions and of the quality of the fluidflowing through it. Therefore it is alwaysrecommended to establish a programme of periodical

inspections, depending either of the type and thespecific characteristics of the valve or of operatingconditions requested from the valve. In order todetermine the recommended maintenance, it issuggested to consult the specific operating manual of

each particular type of valve.




REGULATING NEEDLE VALVE

- GENERALITY:

The needle valve controls the water flow-rate through theaxial movement of a shutter operated by a connecting-rodand crank mechanism.The shutter runs in a pressure-compensated chamber specially shaped to avoid vibrations and anomaloushydrodynamic loads. Closure is in the flow direction, so asthe speed of the fluid (or the pressure difference) increa-sed, the system tends to become even more stable. Theinternal profile of the valve is designed to minimizecavitation effect. The flow of water is channelled into around-section passage which gradually becomes narrower from the intake to the sealing seat.The hydrodynamic profile of the passage is optimizedthroughout the part where the water speed gradually rises,and allows pressure drops to be kept low for degrees of opening in excess of 40%.In short, the needle valve allows gradual reduction in flow-rate for degrees of opening in excess of 40% approx., andhigh dissipation for lower flow-rates.

- INSTALLATION AND START-UP:

First of all rules given at the begining of this book should befollowed in order to guarantee a proper installation.The normal mounting position of the needle valve in anhorizontal pipe is corresponding to an horizontal position of the shaft; however, any other position can be choosen,without negative influence for the valve.In any case mounting position of the needle valve in thepipeline is corresponding to the ones given by the arrowcasted in its body, which should matching the direction of flow of the pipe.

Reverse flow-sense can be accepted only with

complete open valve without any necessity of

regulation.

Further it is always positive to include in the mounting of aneedle valve, starting at the DN 150, a dismantling joint,which has to be assembled at the downstream side of the

valve.If the valve is mounted in the system after having beenstocked for a long period of time, it is advisable to operateit several time in pressureless condition, in order to checkthat every component of the valve is functioning correctly.

As already stated, it is very important to have at thecommissioning time of the valve a very clean pipe, havingbeen flushed correctly in order to avoid that foreign solidparticles (welding slags, residual parts of the pipeassembling work, etc.) are damaging the internalcomponents of the valve, in particular the seat and therubber seat ring, which would prevent any positivetightness.

PAY ATTENTION, WHEN YOU OPERATE OUR NEEDLE

VALVE, TO THE MECHANICAL POSITION INDICATOR

ON THE EXTERNAL GEAR BOX.

INFACT OUR VALVE IT IS NOT 90° OPERATION

(OPEN/CLOSED) BUT LESS THEN IT.WHEN YOU CHECK OPEN POSITION THE INDICATOR

ARROW WILL NOT BE IN CORRISPONDANCE WITH

THE SIMBOL CASTED ON THE GEAR BOX.

- VALVE WITH ELECTRICAL OPERATOR:

When the needle valve is delivered with an electricalactuator, the valve user has to supply the electrical panelfor controlling the valve motor operation (if this one has notbeen ordered as accessory of the valve) and the respectiveelectrical wiring.

As standard, the electrical actuator is equipped with thefollowing items:- limit switches (closed/open position);- torque switch (closing/open operation);

-thermostatic switches (thermoswitches) protecting theelectrical against overheating;

- operating switch, indicating the actuation of the disc(closing/opening operating);

- heating resistance against condesation formation;- Electronic position transducer (4-20 mA) or potentio-

meter (0-200/500/1000/5000 ohm).

The electrical wiring should be made according to theelectrical diagram delivered with the valve; in particular itshould be checked that the phases are connectedcorrectly, in order to secure the prescribed direction of rotation.

Any opposite direction of rotation can produce importantdamage in the gear box or in the valve, since the torquesafety is NOT operating with a wrongly produced reversedrive. In reality if one electrical phase is inverted, no abovestandard described contact is working any more.Therefore a closing rotation will push the obturator againstthe body seat, but since no limit or torque switch will beactuated, the mechanical effort created by the motor willproduce the rupture of one of the components forming thedriving assembly (gear box, motor, valve), which would actas a fuse.Normally the electrical actuator is tested and set-up in thefactory when it is assembled with the needle valve.However it is necesary, after having checked thoroughlythe electrical wiring, to operate the valve a few times for controlling its perfect operation. It is further recommendedto start the electrical tests with the obturator in theintermediate open position, in order that it can be checkedthat the closing operating switch signal is effectivelycorresponding to the closing of the valve obturator (or opposite way) without damaging any component of thedriving assembly (CLOSING SIGNAL/DISC CLOSING).

- MAINTENANCE:

Any maintenance operation requested by the needle valvehas to be made ONLY when the system has been emptied




completely, in order to avoid any accident for theresponsable operator.The needle valve are designed, manufactured and testedvery carefully; the choice of the material of their variouscomponents is made on a very selective way, paying in

particular a lot of attention to the fluid analysis and to theparticular conditions of service.Further all mechanical parts submitted to friction wear aremade with self-lubrificating material, which is not requestingany particular maintenance. In order to keep thisparticularity, it is however necessary to operate the valve atleast once a year, for a total cycle "OPENING/CLOSING"or opposite way.However, specific condition of service or risk of damagecreated by external conditions of installation may requestsome additional yearly maintenance, which has to bedefined for any particular case.

- Replacement of the rubber seat ring:This kind of valve do not need a perfect thightnessbecause of for regulating service it is not requested on theinstallation. In any case the particular design of the valvepermits the easy replacement of the sealing ring, withouteven taking the valve out of the pipe.Following steps to achieve (refere to catalog drawing):- bring the needle valve in the open position;- take out the eventual dismantling joint;- if the installation it is big enough leave valve mounted

on the pipe;- loose the adjusting screws on the retaining ring by

unscrewing them of 1/2 turn;

-unscrew and remove all fixing screws;

- remove the retaining ring; - remove the original rubber sealing ring; clean throughly

the seat and mount the new rubber seat ring(recommended spare part);

- mount back the retaining ring, paying attention to thereference mark which should be matching again theone of the disc and hold it by mounting the fixingscrews, but without tightening them (screws should beloose of at least 1 turn!);

- screw the adjustin screws of 1/2 turn;- tighten and block the fixing screws;- mount back the dismantling joint.

- RECOMMENDED SPARE PARTS:

- sealing ring, to be stocked in a dry and cool locationnot exposed to the sunlight

- kit of internal gaskets.- If valve is manual operated suggested one handwheel

with its respective fixing screw- For electric operation consider as spare parts

recommended:- Electric actuator handwheel complete with its shaft- Set of gaskets

-Limit switches contact.

operating manual needle version1.pdf

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