PDF GB/T 14478-2025 English (GB/T 14478-2012: Older version)
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Basic technical specification of inlet valves for large and medium-sized hydraulic turbines
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Fundamental technical requirements for large and medium inlet valves of hydraulic turbine
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GB/T 14478-2025: PDF in English (GBT 14478-2025) GB/T 14478-2025
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.140
CCS K 55
Replacing GB/T 14478-2012
Basic technical specification of inlet valves for large and
medium-sized hydraulic turbines
ISSUED ON. FEBRUARY 28, 2025
IMPLEMENTED ON. SEPTEMBER 01, 2025
Issued by. State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 7
2 Normative references... 7
3 Terms and definitions... 8
4 Basic technical requirements... 9
5 Method for compiling the model of inlet valve... 13
6 Test methods... 13
7 Installation and operation... 15
8 Complete set supply scope... 16
9 Acceptance and guarantee... 16
10 Nameplate, packaging, transportation, storage... 17
Annex A (informative) Schematic diagram of some structural parts of bimetallic seal
water inlet ball valve... 18
Annex B (normative) Method for compiling inlet valve model... 19
Annex C (informative) Inlet valve spare parts... 21
Basic technical specification of inlet valves for large and
medium-sized hydraulic turbines
1 Scope
This document specifies the basic technical requirements and model compilation
method for inlet valves for large and medium-sized hydraulic turbines. It describes the
test methods.
This document applies to the design, manufacture and acceptance of turbine inlet valves.
butterfly valves with a nominal diameter of 1000 mm~10000 mm and ball valves with
a nominal diameter of 500 mm~5000 mm.
Other butterfly valves and ball valves (including storage pumps, water regulating
pumps and pump-turbines) shall be implemented in accordance with this document.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 150 (all parts), Pressure vessels
GB/T 191, Packaging and storage marks
GB/T 2900.45, Electrotechnical terminology -- Hydroelectric powerplant machinery
GB/T 8564, Technical specification for installation of hydraulic turbine-generator
unit
GB/T 9652.1, Specification of hydraulic turbine governing systems
GB/T 9652.2, Testing specification of hydraulic turbine governing systems
GB/T 15468-2020, Fundamental technical requirements for hydraulic turbines
GB/T 22581-2008, Fundamental technical requirements for Francis pump-turbines
GB/T 28546, Specification for package, transportation and storage of large and
medium hydraulic units
GB/T 40582, Basic terminology of hydropower station
DL/T 1066, Hydropower station equipment maintenance management guidelines
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 2900.45
and GB/T 40582 as well as the followings apply.
3.1 nominal diameter of inlet valve; D
The minimum inner diameter of the valve body where the inlet valve is connected to
the upstream and downstream pressure water pipe flanges.
NOTE. The unit is millimeter (mm). If the inner diameters on both sides are different, the smaller
value shall be taken.
3.2 maximum static head; Hst
After the inlet valve is closed, the water column height formed from the horizontal
center line of the inlet valve to the normal water level upstream.
NOTE. The unit is meter (m).
3.3 maximum static pressure; pc
After the inlet valve is closed, the water pressure formed from the horizontal center line
of the inlet valve to the normal water level upstream.
NOTE. The unit is megapascal (MPa).
3.4 maximum momentary pressure; pm max
The maximum gauge pressure generated at the horizontal center line of the inlet valve
during the transition process.
NOTE. The unit is megapascal (MPa).
3.5 design pressure; pd
The pressure used for strength design of flow-through parts of inlet valves of turbines.
NOTE. The unit is megapascal (MPa).
3.6 test pressure; pt
The pressure used for on-site testing of turbine inlet valves and pressure-bearing parts
of piping systems in factories or construction sites.
NOTE. The unit is megapascal (MPa).
3.7 extension section
A pipe section connecting the upstream side of the inlet valve to the upstream pressure
water pipe.
3.8 expansion joint
A pipe section with telescopic function that connects the downstream side of the inlet
valve to the downstream pressure water pipe (such as a volute or a water distribution
ring pipe).
3.9 assembly of inlet valve
An assembly consisting of valve body, valve, valve shaft, swing arm and seal.
3.10 hydraulic power self-excited oscillation
Any small disturbance in pressure or flow introduced into an unstable hydraulic system
will result in vibrations that grow over time.
4 Basic technical requirements
4.1 The design pressure of the inlet valve shall not be less than the maximum transient
pressure. The design, manufacture and inspection of the inlet valve and the pressure-
bearing parts of the piping system shall comply with the provisions of GB/T 150 (all
parts), 4.2.1.21 of GB/T 15468-2020 and 4.2.1.21 of GB/T 22581-2008.
4.2 When the unit is shut down normally or under maintenance, the inlet valve shall be
closed reliably.
4.3 Under any operating condition of the unit, the inlet valve shall be closed by dynamic
water and shall not produce harmful vibration that causes permanent deformation.
4.4 The working state of the inlet valve shall be in the fully open or fully closed position.
It shall not be used to adjust the flow.
4.5 The profile design of the butterfly valve shall avoid vibration caused by Karman
vortex.
4.6 When the pressure difference on both sides of the inlet valve is no more than 30%
of the maximum static water pressure, it shall be opened normally.
4.7 The assembly of inlet valve shall be assembled at the manufacturer. After assembly
and installation in the power station, it shall ensure flexible movement and accurate full
open and full closed positions. When the inlet valve is not assembled at the
manufacturer, the servo does not participate in the assembly, but the servo shall be tested
separately for sealing leakage, movement and stroke inspection, etc. The opening and
closing time of the inlet valve shall be adjustable.
4.8 The following parts of the inlet valve structure shall be replaced without
disassembling the valve body.
a) Valve shaft seal ring and valve downstream seal ring;
b) Metal fixed seal ring and movable seal ring on the downstream side of the valve,
see Annex A for details;
c) Valve shaft bearing.
4.9 The butterfly valve seal shall be solid and set on the downstream side of the butterfly
valve. The belt and the sealing seat shall have sufficient compression. If the butterfly
valve seal adopts air belt seal, it is advisable to adopt a uniform standard cross-sectional
size of 50 mm outer diameter and 30 mm inner diameter. The working air pressure of
the belt shall be 0.1 MPa~0.2 MPa higher than the maximum hydrostatic pressure. The
maximum air pressure is allowed to be adjusted to 0.4 MPa higher than the maximum
hydrostatic pressure.
The fixed sealing ring of the inlet valve (if any) is required to fit tightly at the sealing
pair, see Annex A for details.
4.10 The inlet valve shall be equipped with a reliable automatic hydraulic locking
device in the fully closed position. A manual mechanical locking device for
maintenance shall be installed in the fully open and fully closed positions.
It is not advisable to install an automatic hydraulic locking device when the inlet valve
is in a fully open position.
The inspection seal of the inlet valve shall be equipped with a reliable mechanical
locking device.
4.11 The inlet valve shall be equipped with a bypass valve, or other structures that can
play the same role shall be used. An expansion joint shall be installed for the bypass
pipeline that crosses the expansion joint. Reliable fixing measures shall be taken for the
bypass pipeline. If a bypass valve flat pressure structure is used, its nominal diameter
shall not be less than 10% of the nominal diameter of the inlet valve.
4.12 The inlet valve shall be equipped with an air valve, or other structures that can
play the same role shall be adopted. The air valve shall have the function of automatic
air inlet and exhaust. Its nominal diameter shall be within the range of 5%~10% of the
nominal diameter of the inlet valve.
4.13 The inlet valve shall be equipped with an expansion joint on the downstream side.
Its structure shall be easy to install and disassemble. After installation in the power
station, the expansion joint seal is not allowed to leak.
4.19 According to the actual use conditions of the inlet valve, the material of the inlet
valve shall comply with the following requirements.
a) The extension section and expansion joint shall be made of materials with good
weldability.
b) Anti-rust measures shall be taken at the parts where the valve shaft contacts the
bearing and the valve shaft seal.
c) The inspection seal of the inlet valve and the working seal of the ball valve shall
be made of stainless steel. The working seal of the butterfly valve shall be made
of non-metallic seal.
d) Anti-rust measures shall be taken on the relative sliding surfaces of the movable
sealing ring and the valve body.
e) The metal sealing surfaces of the movable sealing ring and the fixed sealing ring
shall be made of cavitation-resistant and anti-sand wear materials.
f) The valve fixed sealing pressure plate and pressure plate screws shall be made of
stainless steel. Anti-loosening measures shall be taken for the pressure plate
screws.
g) The air belt or solid sealing belt shall be made of high-quality wear-resistant and
water-resistant materials.
h) The valve shaft seal of the inlet valve shall be made of water-resistant and wear-
resistant materials.
i) The working sealing surface of the bypass valve and air valve shall be made of
cavitation-resistant and anti-sand wear materials. The valve stem shall be made
of stainless steel.
j) The valve shaft bearing shall be made of self-lubricating material.
4.20 The structural type of the inlet valve shall comply with the following requirements.
a) The inlet valve shall be arranged with a horizontal axis.
b) The valve of the inlet valve shall be opened by hydraulic operation. It can be
closed by hydraulic pressure, heavy hammer operation or a combination of them.
c) The inlet valve shall be equipped with a single relay or a double relay. The relay
shall be arranged on the valve chamber layer foundation, or it can be suspended
on the valve body.
d) The butterfly valve can adopt a single seal or double seal structure. The sealing
pair can be metal-metal and metal-non-metal.
e) The ball valve shall adopt a double seal structure.
f) The movable sealing ring of the ball valve shall be optimized through structure to
delay the hydraulic self-excited vibration of the inlet valve.
g) A valve with sewage and water discharge functions shall be set at the bottom of
the inlet valve. A maintenance valve shall be set in front of the valve. The layout
of the sewage pipeline shall take into account the expansion and contraction
deformation and the convenience of assembly and disassembly. Increase the
foundation anti-jamming requirements.
h) The pressure water pipe filling and drainage valve shall use a manually operated
needle valve or ball valve. The design pressure level shall not be lower than the
design pressure of the inlet valve. Inspection valves shall be installed before and
after the filling and drainage valves. The first inspection valve connected to the
pressure water diversion pipe shall be a manually operated ball valve made of
stainless steel.
i) The oil pressure device of the inlet valve shall be designed, manufactured and
accepted in accordance with GB/T 9652.1.
j) The control system of the inlet valve shall be designed, manufactured and accepted
in accordance with GB/T 9652.2.
5 Method for compiling the model of inlet valve
The model compilation method of the inlet valve shall be in accordance with the
provisions of Annex B.
6 Test methods
6.1 Inlet valve assembly test
Usually according to the contract requirements, the inlet valve shall be subjected to the
following tests after assembly in the manufacturing plant.
a) The valve body and extension section of the inlet valve shall be subjected to a
strength water pressure test. The test pressure shall be 1.5 times the design
pressure. The test time shall be 30 min. Permanent deformation, leakage and other
abnormal phenomena are not allowed.
b) The valve shall be subjected to a strength water pressure test. The test pressure
shall be 1.2 times the design pressure. The test time shall be 30 min. Permanent
deformation, leakage (except for the valve seal) and other abnormal phenomena
are not allowed.
Where,
Dc - Inner diameter of the servo cylinder, in millimeters (mm);
q - Maximum allowable oil leakage, in milliliters per minute (mL/min);
p - Rated working oil pressure, in megapascals (MPa).
c) If it is a hydraulic straight cylinder servo, the piston seal shall be tested for water
leakage. The water leakage is calculated according to formula (2).
When the sealing leakage test is carried out under the rated working water pressure
conditions, the relay is not allowed to leak.
6.3 Requirements for valve watertight seal test and flaw detection
When the design pressure is less than or equal to 0.6 MPa, the water sealing weld of the
inlet valve shall be subjected to kerosene penetration test. It is required that no
penetration shall occur. When the design pressure is greater than 0.6 MPa, magnetic
particle or color flaw detection shall be performed.
6.4 Dynamic water shut-off test
Before the dynamic water shut-off test of the inlet valve is carried out, a detailed test
outline shall be formulated with the equipment contractor to ensure the safety of the
test. After the dynamic water shut-off test, the inlet valve and its ancillary equipment
shall be inspected according to the requirements of the test outline.
7 Installation and operation
7.1 During installation on site, the requirements of GB/T 8564 and the drawings and
relevant technical documents of the equipment contractor shall be followed.
7.2 The oil, water and gas pipelines formed and welded on site shall be subjected to
water pressure or oil pressure test. The test pressure shall be 1.5 times the design
pressure of the corresponding pipeline and the test time shall be 30 min.
7.3 When the expansion joint and extension section are welded to the volute (water
distribution ring pipe) or pressure water diversion pipe at the construction site, the
welding deformation shall be strictly controlled to ensure the verticality of the flange
surface and the coaxiality with the center line of the inlet valve. Ensure that the gap
around the expansion joint is uniform and meets the requirements of the drawing. The
weld shall be 100% non-destructive inspection.
7.4 The operation shall be carried out strictly in accordance with the relevant technical
documents and automated operation procedures. The inlet valve equipment and
accessories shall be maintained regularly.
7.5 If hydraulic self-excited vibration occurs during the operation or maintenance of the
ball valve, it can be eliminated by opening the bypass valve or inserting the maintenance
sealing ring.
8 Complete set supply scope
8.1 The complete set of inlet valves operated by oil pressure or water pressure shall
include.
a) Inlet valve body and operating mechanism, extension section, expansion joint,
bypass valve and bypass pipeline (if any), air valve (if any), oil collection device,
relay operating water main/standby filter and valve, seal control water precision
filter, pipeline and its accessories, etc.;
b) Oil pressure device, oil pump group and hydraulic control device, etc.;
c) Automatic control components;
d) Spare parts of inlet valve, see Annex C for details.
8.2 Special tools and spare parts for installation, disassembly and maintenance of inlet
valves.
8.3 The following technical documents shall be provided for each inlet valve.
a) Product installation, use and maintenance instructions;
b) Delivery details list;
c) Factory product inspection and test record card;
d) Main assembly drawing, foundation force diagram, hydraulic device diagram,
automatic operating system diagram, main parts diagram, special tool diagram,
and wearing parts processing diagram.
NOTE. The types of drawings in item d) shall be specified in the technical conditions agreed upon
between the purchaser and the equipment contractor.
9 Acceptance and guarantee
9.1 Inlet valve products and main components shall be inspected and qualified by the
manufacturer before leaving the factory, and shall be accompanied by documents
proving the product’s qualification.
9.2 During the product warranty period, the water leakage of the inlet valve under
normal working conditions shall comply with the provisions of the technical agreement
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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