File

DWS 2510: STANDARD SPECIFICATION: SUPPLY OF VALVES

STANDARD SPECIFICATION

DWS 2510SUPPLY OF VALVES

PARTICULAR VALVE SPECIFICATION

SLEEVE VALVES

TO BE READ IN CONJUNCTION WITH THE PROJECT SPECIFICATION AND

SECTION DWS 2510/01 – GENERAL TECHNICAL SPECIFICATION

DWS 2510/03- SLEEVE VALVESJUNE 2000

COVER PAGE


INDEX

PAGE

1. GENERAL....................................................................................................................................... 2

1.1 AMBIENT / OPERATING CONDITIONS.............................................................................................21.2 INSTALLATION............................................................................................................................. 21.3 OPERATION................................................................................................................................ 2

2. CONSTRUCTION AND OPERATIONAL REQUIREMENTS..........................................................2

2.1 VALVE DESIGN WITH THE BACK SEAL ATTACHED TO THE SLIDING SLEEVE:......................................22.2 VALVE DESIGNS INCORPORATING THE BACK RUBBER SEAL IN THE BARREL POSITION OF THE BODY. 32.3 SEALS....................................................................................................................................... 32.4 OPERATING MECHANISM.............................................................................................................32.5 POSITION INDICATORS................................................................................................................32.6 FLOW DISCHARGE CHARTS..........................................................................................................32.7 HOODS...................................................................................................................................... 4

3. VALVE MATERIAL SPECIFICATION............................................................................................4


1


1. GENERAL

Valves are generally required to facilitate scour operations of pipelines and control the flow of water from dam outlet systems.

1.1 AMBIENT / OPERATING CONDITIONS

Valves and controls shall be exposed to the weather and sunlight and shall be non operative for extended periods of time. Design shall allow for dependable operation under these conditions.

1.2 INSTALLATION

The installation of this type of valve shall either be horizontal or inclined to a maximum angle of 30 degrees above the horizontal plane. The sleeve valve will be installed onto a pipe reducer.

1.3 OPERATION

For hand wheel operated sleeve valves, valve operation shall be via a stainless steel stem and a thrust head mounted on a trunnion for horizontal mounting or where so indicated, cast into a wall. The lever operated linkage shall be designed to accommodate movement restraints which may arise as a result of casting the trunnion into the wall.

When hydraulic operation is required, the hydraulic power pack and cylinders shall be in accordance with Auxiliary Drive Specification.

2. CONSTRUCTION AND OPERATIONAL REQUIREMENTS

Valves shall be of the sliding sleeve, inverted cone, jet dispersing type with acceptable actuation by means of hinged levers or hydraulic cylinders.

The valve designs shall ensure that the sliding sleeve cannot be distorted, due to over travel and over stressing of the sliding sleeve at the point of closure.

Operating mechanisms in or across the waterway are not acceptable, the only acceptable obstructions in the waterway are the streamlined radial ribs carrying the valve cone and seat.

The sleeve shall be guided throughout the travel to prevent sleeve rotation during operation due to unbalanced pressures.

The following two sleeve valve designs are acceptable:

2.1 VALVE DESIGN WITH THE BACK SEAL ATTACHED TO THE SLIDING SLEEVE:

The valve body may be of spheroidal graphite iron, cast or fabricated steel or stainless steel. If the valve body is not manufactured from stainless steel, then a stainless steel grade 304L sleeve shall be shrunk onto the barrel of the body on which the back seal will slide. The back and front seal retaining rings shall be manufactured of stainless steel grade 304 or equal.


2


The radial rib edges, in the water port area, shall have machined stainless guide strips. These stainless steel strips shall be screwed (assembled while the paint is still wet) or continually welded to the rib edges to prevent crevice corrosion.

The sliding sleeve may be constructed from spheroidal graphite iron, cast steel, aluminium bronze, fabricated steel or corrosion resistant steel and shall incorporate a stainless steel seat ring which will seat against a renewable front rubber seal when the valve is in the closed position.

2.2 VALVE DESIGNS INCORPORATING THE BACK RUBBER SEAL IN THE BARREL POSITION OF THE BODY

The valve body may be of spheroidal graphite iron, cast or fabricated steel or stainless steel. The front rubber seal on the cone shall be out of the waterway and positively held in position by a stainless steel grade 304 securing ring and shall not depend on friction for retention.

The rib edges shall be protected by brass strips screwed (assembled while the paint is still wet) to the rib edges. The sliding sleeve may be of stainless steel, aluminium bronze or the internal bore of the sleeve may be stainless steel clad.

Valves shall provide tight shut-off, in other words, there shall be no leakage past the sealing faces when a pressure equal to the working pressure is applied to the valve with sleeve in the closed position.

2.3 SEALS

For both concepts the polymer seals shall be replaceable in-situ. Seals shall be positively secured in position by stainless steel securing elements or retaining rings. The seals shall be installed in locations out of the waterway

2.4 OPERATING MECHANISM

Pins shall be permanently secured to the associated lever arms or linkages. The lever arms and linkages shall be adequately designed to prevent distortion or bending of the arms during the valve operational cycle.

2.5 POSITION INDICATORS

Mechanical or electronic valve position indicators, calibrated in specified increments of the openings, shall be designed, supplied and installed as indicated elsewhere in the tender documents.

2.6 FLOW DISCHARGE CHARTS

A flow discharge chart shall be supplied for each size of sleeve valve, showing the water flow rate (m3/s) against the head (metres) at various percentages of valve opening. The water head shall be given in increments of 1 metre and the valve opening in increments of 10 % from 0 to 100 % open. Each chart shall have the name of the scheme as well as the size of the valve clearly displayed.

All information contained in the charts shall be engraved and painted on 2mm thick aluminium plates (minimum size A2).


3


2.7 HOODS

Should hoods be required for the sleeve valves these shall be fabricated from stainless steel Grade 316L; and must have incorporated in its design, suitable integral support pedestals for mounting onto the concrete base and lifting lugs for handling purposes. Stainless steel mounting bolts, nuts and washers shall be supplied to fix the hoods to the concrete plinth.

The hoods shall be designed to give a continuous flow, free from the vibration and the back flow kept to a minimum.

Drainage holes, diameter 50mm minimum, are to be provided in all pockets where water is likely to accumulate.

The hood shall be designed to facilitate easy removal of the sleeve valve. When the design incorporates a removable segment for removal of the sleeve valve, a suitable lifting point on the segment must be provided. All fasteners for the fitment of the segment into the hood body shall be provided.

3. VALVE MATERIAL SPECIFICATION

Valve components shall be constructed of the materials as specified in the following table unless otherwise specified in the Project specification.

SIZE DN PRESSURE RATINGKpa

HYDRAULIC TESTPRESSURE IN kPa

150-1400

200 - 1200

1000 / 1600

2500 / 4000

STRUCTURAL SEAT1500 / 2400 1000 / 1600

3750 / 6000 2500 / 4000

COMPONENT MATERIAL TYPE MATERIAL SPECIFICATION

BODY MILD STEEL CAST STEEL

BS 4360 Gr 43BS 1504-161, SABS 1465 Part 1

SLEEVE STAINLESS STEEL BS 970 Part 4 Gr 304 S15

CLAMP RING STAINLESS STEEL BS 970 Part 4 Gr 304 S15

BEARINGS ELASTOMER PTFE

SPACER STAINLESS STEEL BS 970 Part 4 Gr 304 S15

SEAL RINGS O RING NITRILE / VITON / EPDM

HOOD (Where applicable) CORROSION RESISTANT M/S

HYDRAULIC CYLINDER STAINLESS STEEL BS 970 Part 4 Gr 304 S15

COTTER PINS STAINLESS STEEL BS 970 Part 4 Gr 431 S29

ANTI –ROTATION BAR STAINLESS STEEL BS 970 Part 4 Gr 431 S29

INSULATION GASKETS BS 1832 Gr A

INSULATION SLEEVES AND WASHERS COMPRESSED FIBRE RESIN

LINK ( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 304 S15


4


SIZE DN PRESSURE RATINGKpa

HYDRAULIC TESTPRESSURE IN kPa

150-1400

200 - 1200

1000 / 1600

2500 / 4000

STRUCTURAL SEAT1500 / 2400 1000 / 1600

3750 / 6000 2500 / 4000

COMPONENT MATERIAL TYPE MATERIAL SPECIFICATIONLEVER CRANK ASSEMBLY

( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 304 S15

PIVOT SHAFT ( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 431 S29

BUSH PIVOT SHAFT ( If actuated ) VESCONITE

CLEVIS ( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 304 S15

ROLLER ( If actuated ) ALLOY STEEL

BUSH CLEVIS SHAFT ( If actuated ) ELASTOMER PTFE

CLEVIS SHAFT ( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 431 S29

DRIVE SHAFT ( If actuated ) STAINLESS STEEL BS 970 Part 4 Gr 431 S29

GLAND FOLLOWER ( If actuated ) PHOSPHOR BRONZE BS 1400 PB1C (Cu,Sn10,P)

GLAND PACKING ( If actuated ) GRAPHITE PACKING NOTE: NO ASBESTOS

PEDESTAL ( If actuated ) CAST STEEL BS 1504 -161 Gr 480, SABS 1465 Part 1

GLAND BUSH ( If actuated ) PHOSPHOR BRONZE BS 1400 PB1C (Cu,Sn10,P)

INDICATOR PLATE ( If actuated ) HIGH TENSILE BRASS BS 2872 CZ 114

POINTER ASSEMBLY STAINLESS STEEL BS 970 Part 4 Gr 304 S15

EXTERNAL FASTENERS STEEL

(HOT DIP GALVANISED)SABS 163 Gr 8.8

INTERNAL FASTENERS STAINLESS STEEL ASTM A193 Gr B8M, ASTM A439 Gr D2

OPERATION ARRANGEMENT GEARBOX SEE AUXILIARY DRIVE SPECIFICATION

ELECTRIC ACTUATOR SEE AUXILIARY DRIVE SPECIFICATION

HYDRAULIC ACTUATOR SEE AUXILIARY DRIVE SPECIFICATION


5

File

Documents

Transcript of File