Is 7332 1 1991
Is 7332 1 1991
Is 7332 1 1991
( q~~T tj~~TelU1 )
Indian Standard
SPHERICAL VALVES FOR HYDROPOWER
STATIONS AND SYSTEMS
PART 1 CRITERIA FOR STRUCTURAL AND HYDRAULIC DESIGN
( fl"rsl Revision)
OBIS 1991
8 r: n E A LJ () FIN D I A N S TAN I) A R II S
rvlANAK BHAVAN. 9 BAllAOUR SHAH ZAFAH. t\-IARG
NE\V DELHI 110002
( Page I, clause S.l ) - Substitute the following for the existing text:
'The body of the valve should be: designed for various loading conditions given
in IS 11639 (Part I),IS 11639 (Part 2) and IS 11639 (Part 3):
( Page 4, clause 6.4.1, para 2 ) - Delete.
( Page 5, Annex A ) - Delete 'IS 226 : 1975 Specification for structural
steel (standard quality) (fifth rt!vision)' .
(Page 5, Annex A ) - Substitute 'IS 1030: 1998 Specification for carbon
steel castings for general engineering purposes (fifth revision)' for 'IS 1030 :
J982 Specification for steel castings for general engineering purposes (fourth
revision)'.
( Page 5, Annex A) - Substitute 'IS 2002 : 1992 Specification for steel
plates for pressure vessels for intermediate and high temperature service
including boilers (second revision)' for 'IS 2002 : 1982 Specification for steel
plates for pressure vessels for intermediate and high temperature service
including boilers (first revision)'.
( Page 5, Annex A ) - Substitute 'IS 2004 : 1991 Specification for carbon
steel forgings for general engineering purposes (third revision)' for 'IS 2004 :
1978 Speci fication for carbon steel forgings for general engineering purposes
(second revision)'.
( Page 5, Annex A ) - Substitute 'IS 2062 : 1999 Specification for steel for
general structural purposes (fifth revisionr for 'IS 2062 : 1984 Specification for
weldable structural steel (third rev;swnf.
( Page 5, Annex A ) - Substitute 'IS 2708 : 1993 Specification for 1.5
percent manganese steel castings for general engineering purposes (third
revision)' for 'IS 2708 : 1984 Specification for 1.5 percent manganese steel
castings for general engineering purposes (J~cond revision)'.
Amend No.1 to IS 7332 ( Part 1 ) : 1991
(WRD12)
ReproaraphyUnit.81S, NewDell1i, Indil
2
Hydraulic Gates and Valves Sectional Committee, RVD 12
I·OREWORD
This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the
Hydraulic Gates and Valves Sectional Committee had been approved by the River Valley Division
Council.
Spherical valve is a shut-oil" device most commonly used in Hydro-power stations for a head 200 III
and above. These valves may be used at lower heads also if desired by the designer. Its use is
favoured at high heads as there is no hydraulic loss due to valve itself when valve is open and
provided a better tight sealings when valve is closed.
Basically spherical valve consists of spherical shaped body air valve and water/oil pressure system or
any other control system are required for operation of spherical valves.
This standard covers only the guidelines (criteria) for structural and hydraulic design or valves so
as to permit necessary flexibility in their detailed design as per requirements of the designer.
These guidelines are based on the available expertise and the practices prevaling in this field at
present so that the same could be utilized. As and when some more information is available the
same will he incorporated in the standard. Therefore these are expected to he used by those
designers who have sufficient knowledge in this field.
This standard is being published In parts. Part I deals with structural and hydraulic aspects or
design. Part 2 deals with the guidelines for design and selection of the control equipment used in
spherical valves. Part 3 deals with the. operation and maintenance of spherical valves.
This standard (Part I) was first published in 1974. This revision is being done on the baSIS of
experience gai ned during the use of this standard for the last 16 yean as well as the experience
gained during this period in the operation of these valves at the various power stations. The
principal modifications made in this revision arc as below:
a) In the construction provision or conical shape body has also been made;
h) The provision of rubber type seals has been deleted;
c l Self-lubricated bushes have been added:
d) Permissible bearing stress level has been increased h) 35 Njmm"; and
c) Clauses for, ( 1 ) hydraulic condition of design, ( .2 ) design criteria for by pass valve, scaling
valve and air valve. (3) permissible leakages have been added.
For the purpose or deciding whether a particular requirement of this standard is complied with the
final value, observed Of calculated. expressing the result ora test or analysis. shall be rounded off
in accordance with IS 2 : 1960 "Rules for rounding off numerical values i revised r. The number
of significant places retained in the rounded otT value should be the same as that of the specified
value in this standard.
IS 7332 ( Part 1 ) : 1991
India11 Standard
SPHERICAL VALVES FOR HYDROPOWER
STATIONS AND SYSTEMS
PART 1 CRITERIA FOR STRUCTURAL AND HYDRAULIC DESIGN
( First Revision )
1 SCOPE 6 DESIGN OF t\fECHANICAL !)ARTS
1.1 This standard (Part 1 ) lays down the. guide- 6.1' Valve Body
lines (criteria) for the structural and hydraulic
design of spherical valves for hydropower stations. 6.1.1 The valve body may be cast or fabricated
or cast fabricated from materials recommended in
2 REFERENCES Annex B. The body shou ld have two holes for
The Indian Standards listed in Annex A are trunnion bearing housings and suitable bosses for
necessary adjuncts to this standard. by-pass connection, drainage, air release and for
mechanical locks if necessary. Flanges for con-
3 STANDARD SIZES necting to penstock should be at right angle to
the axis of the bore and concentric with the bore
3.1 As far as possible, the valves should be and the faces should be parallel. The flanges
designed in any of the following sizes ( in 111m ): should have tapped or through holes. In case
500. 600, 700, 800, 900, I 000. 1 100, I 20H, repair sea I has been provided, it should have a
1 300, 1 400, 1 500, I 600, I 800, 2000, boss on upstream side for connection of a pipe
2 200, 2400, 2 600. 2 800, 3 000, 3 200, for equaliz.ing pressure and on inlet side a
3 400, 3 600, 3 800. 4 000 and 4 200. cylindrical surface lined with stainless steel should
he provided where movable ring of repair seal
3.2 Size of the valve should normally be the same slides. This may be provided only in case valve
as that of inlet dia of the spiral case/distributor. has got repair seal arrangement. On the outlet
However reduction in the size if any can be side it should have a cylindrical surface for
considered by user taking into consideration the fitting the service seal.
extra head loss in the reducer and expander.
6.1.2 The body should be made in two parts from
4 TYPE OF VALVES AND THEIR USE assembly point of view. The joint may be vertical,
horizontal or diagonal according to the suitability
4.1 Normally two types of valves are designed: of assembly and transport. For large valves the
body may be made in more than two parts having
a) Valve with service seal only, and joint in vertical as well as in the horizontal plane.
b) Valve with service and repair seals. The joint in horizontal plane gives possibility of
assembling the valve directly at the place of
Typical details of valves with disc type and piston installation. Two halves should have necessary
type seals ( for service and repair seals) are shown spigots and sockets, seal provision, locating
in Fig. 1 and 2.
arrangement and should be held together by
4.1.1 For a station having long penstock or re- means of sufficient number of bolts and studs.
quiring unit isolation it is recommended to use 6.1.3 The fasteners of parting flanges and two
the valve with both the seals, that is service as end flanges should be tightened with specified
well as repair seals. Repair seal jives possibility initial tightening by heating or slogging or by
of changing the service seal without draining the hydraulic bolt tensioner to have controlled total
long penstock which may take more time or may stresses developed in the fasteners.
require closing of gates.
5 Hydraulic Conditions for Design 6.1.4 The body should be designed, such as to
sustain maximum pressure including water
5.1 The body of the valve should be designed for hammer. Supporting feet for installing the valve
the condition of dynamic head, which is the head on foundation should be provided. These feet, or
attained after closure of the turbine. part thereof. are to be integral with the valve
Dynamic hcad=Max Static headl Pressure rise body, and may not extend beyond the flange faces
head of the valve. These supporting feet should have
holes bigger than the diameter of foundation
5.2 The rotor and trunnions of the valve should bolts to allow for axial movement of valve thus
be designed for the condition of head being avoiding axial load on foundation.
attained after its closure or for the head which is
1'10 times the maximum static head whichever is 6.1.5 Suitable me.ms of adequate strength for
more. lifting the valve should be provided.
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6.3.1 Valve should have hush bearing made from The valve foundations should be designed to
material given in Annex B. Self-centering bearings cater for complete tensile and compressive forces
may be used incase of valve where deflection of produced by operating gear occurring during
trunnions is considerable. It should be designed worst conditions of its operations. No hydraulic
for the maximum load imposed by the rotor. thrust will be taken on the foundations of the
valve in closed position. The purchaser should
6.3.1 Suitable provision should be made for provide a suitable means to sustain thrust in the
lubricating the bearings unless bearings are of penstock design or on the downstream of the
self lubricating type. valve ( by providing a thrust collar or brackets)
as agreed by the purchaser and the supplier.
6.3.3 There should be provided for limiting the
movement of rotor along its axis of rotation. 6.7 Bypass Valve
6.3.4 Bearing should be provided with suitable The size of the by-pass valve should be sufficient
seal for stopping the leakage of water and grease. to balance the downstream pressure at least by
60 percent of the upstream pressure, considering
6.4 Seal the maximum leakages through the guide vanes.
4
IS 7332 ( Part I ) : 1991
ANNEX A
( Clause 2.I )
28 : 1985 Specification for phosphor bronze 2002 : 1982 Specification for steel plates for
ingots and castings (fourth pressure vessels for intermediate
revision) and high temperature service
including boilers (first revision)
226 : 1975 Specification for structural steel 2004 : 197H Specification for carbon steel
(standard quality) ( fifth forgings for general engineering
revision ) purposes ( second revision)
2062 : 19~4 Specification for weldable
318 : 1981 Specification for leaded tin structural steel ( third revision)
bronze ingots and castings
27t)8 : 1984 Specification for l '5 percent
( second revision)
manganese steel castings for
Specification for steel castings general engineering purposes
1030 : 1982
for general engineering purposes ( second revision )
(fourth revision ) 2856 : 1987 Specification for carbon steel
castings for pressure containing
1570 Schedules for wrought steels: parts suitable for high tempera-
( Part 5) : 1985 Part 5 Stainless and heat resis- ture service t fusion welding
tins steels ( second revision) quality) ( third revision)
IS 73'2 ( Part 1) 1991
ANNEX B
( Clauses 6 1 I, 6 2 1, 6 2 2, 6 1 1, 6 4 1 and 6 4 4 )
RI1COMMFNDED MATERIAL~ lOR VARIOU'; COMPONENTS
ANNEX (
( Clause 9 1 )
TESTS TO 81!. PERFORMED ON THE SPHERI(,AL VALVE AND ITS PART~
6
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