GB/T 5656-1994 Technical requirements for centrifugal pumps (Class II)
Some standard content:
National Standard of the People's Republic of China
Technical specifications for centrifugal pumps-Class 1
This standard is equivalent to the international standard ISO5199-1986 "Technical specifications for centrifugal pumps-Class 1". GB/T 5656--94
Replaces GB5656--85
There are three standards for technical specifications of centrifugal pumps, which are divided into Class 1, Class 2, and Class 3. Class 1 has the most stringent requirements, and Class 2 has the loosest requirements. All the contents that may need to be decided by the buyer or need to be agreed upon by the buyer and the manufacturer are printed in bold and listed in Appendix H.
Subject content and scope of application
This standard specifies the requirements for the design, manufacture, factory inspection and delivery of centrifugal pumps. It also includes the design features related to the installation, maintenance and safety of these three pumps (including base, coupling and auxiliary pipeline, excluding the driver). This standard applies to centrifugal pumps of rear-opening structure used in the chemical and petrochemical industries (typically, pumps that comply with the provisions of GB5662).
This standard or some of its clauses apply to the design of pumps that are not rear-opening structures. In cases where the application of this standard has been required: a. When a special design feature is required, other alternative designs that meet the intent of this standard can be selected, as long as they are described in detail;
. Pumps that do not fully meet the requirements of this standard can be proposed for consideration, as long as all non-conformities are explained. When multiple documents contain conflicting technical requirements, the applicability of each document should be determined in the following order; a.
Purchase order or inquiry (if there is no order, see Appendix F (reference) and Appendix G (reference)); Data sheet [see Appendix A (reference));
This standard;
Other standards mentioned in the order or inquiry. 2 Reference standards
GB3216
GB3767
GB3768
GB4216
Test methods for centrifugal pumps, mixed flow pumps, axial flow pumps and vortex pumps Determination of sound power level of sound source Engineering method and quasi-engineering method Determination of sound power level of noise source
Simplified method
Dimensions of flanges for grey cast iron pipes
GB4662
Rated static load of rolling bearings
GB5660
Dimensions of base and installation of axial suction centrifugal pumps GB5661
Dimensions of cavity for mechanical seals and soft packings of axial suction centrifugal pumps (1.6MPa) Marking, performance and dimensions GB5662
Profile method Stylus surface roughness measuring instruments, profile recorders and center line profilers GB 6062
GB 6075
GB6391
Basis for the formulation of machine vibration standards
Calculation method for rated dynamic load and rated life of rolling bearingsApproved by the State Administration of Technical Supervision on August 29, 1994Implementation from July to January, 1995
GB9112Types of steel pipe flanges
GB/T 5656--94
GB9239Balance quality of rigid rotors
Determination of allowable imbalance
GB10889Measuring and evaluating methods for vibration of pumpsGB10890Measuring and evaluating methods for noise of pumps3Definitions
Definitions of terms that must be explained in this standard. 3.1Working conditions
Various parameters (such as working temperature and working pressure) determined by the given application and the pumped liquid. These parameters affect the structural type and structural materials.
3.2 Allowable operating range
The flow range of the pump under specified operating conditions with the impeller provided. This range is subject to cavitation, heat, vibration, noise, shaft deflection and other similar criteria. The operating range should be determined by the manufacturer. 3.3 Rated conditions
The conditions that determine (guarantee) the operating point (excluding the driver). This operating point is required to meet all specified operating conditions and take into account a certain necessary margin.
3.4 Rated output power of the driver
The maximum output power of the driver allowed under field working conditions. 3.5 Basic design pressure
This is the pressure derived from the allowable stress of the material used for pressure-bearing parts at 20°C. 3.6 Rated pressure
The ultimate pressure under the worst operating conditions for a given application. 3.7 Rated inlet pressure
The inlet pressure that together with the rated head (converted into pressure) at the rated flow rate gives the rated outlet pressure. 3.8 Rated outlet pressure
The outlet pressure of the pump at the rated flow, rated head (converted into pressure) and rated inlet pressure. 3.9 Pressure-temperature characteristics
The relationship between pressure and temperature given in the form of a curve (see Figure 1). Medical force
Basic design flow
Working pressure
T. Working temperature
Figure 1 Pressure-temperature characteristics
3.10 Corrosion allowance
GB/T 5656-94
The part of the wall thickness of the part that is corroded by the pumped liquid exceeds the theoretical wall thickness. The theoretical wall thickness is the wall thickness required to withstand the limit pressure given in 4.4.1.
3.11 Maximum permissible continuous speed
The maximum speed at which the manufacturer allows the pump to operate continuously. 3.12 Automatic stop speed
The speed at which the emergency stop mechanism of the steam turbine is actuated. 3.13 First critical speed
The speed of the machine at which the first (lowest) lateral natural vibration frequency of the rotating part of the machine coincides with the frequency of rotation. 3.14 Design load
The maximum hydraulic radial force acting on the impeller when the largest impeller (diameter and width) operates within the range specified by the manufacturer on the (performance) curve at its highest speed under the condition of liquid density of 1000kg/m. 3.15 Maximum load
The maximum hydraulic radial force acting on the impeller when the largest impeller (diameter and width) operates at any point on the (performance) curve at its highest speed under the condition of liquid density of 1000kg/m. 3.16 Shaft radial runout
The total radial deviation indicated by an instrument measuring the position of the shaft relative to the bearing housing when the shaft supported in the bearing is turned by hand with the shaft in a horizontal position.
3.17 Face Runout
The total axial displacement at the radial face of the stuffing box indicated by an instrument attached to and rotating with the shaft when the shaft is turned by hand in a horizontal position. The radial face is the plane that determines the alignment of the seal components. 3.18 Shaft Deflection
This term as used in this standard describes the displacement of the shaft from its geometric center in response to hydraulic radial forces acting on the impeller. It does not include shaft displacement caused by tilting of the shaft within the range of bearing clearances, nor does it include shaft bending caused by impeller imbalance or radial runout of the shaft.
3.19 Circulation (Flushing)
Return of pumped liquid from the high pressure area to the seal chamber can be achieved through external piping or internal passages. The return liquid is used to remove heat generated by the seal or to maintain a positive pressure in the seal chamber, or it is treated to improve the working environment of the seal. In some cases, circulation from the seal chamber to a low pressure area (such as the inlet) may be most desirable. 3.20 Injection (flushing)
Introducing a suitable (clean, compatible, etc.) liquid from an external source into the seal chamber and then into the pumped liquid. Its function is the same as the above-mentioned annular flow, and it is used to provide a good working environment for the seal. 3.21 Compliance
Introducing a suitable (clean, compatible, etc.) fluid continuously or intermittently on the atmospheric side of the main shaft seal. It is used to exclude air or moisture, prevent or remove deposits (including ice), lubricate auxiliary seals, extinguish sparks, dilute, heat or cool leaks. 3.22 Barrier liquid
Introducing a suitable (clean, compatible, etc.) liquid between two seals (mechanical seals and/or soft packing). The pressure of the barrier liquid depends on the sealing device. Barrier liquid can be used to prevent air from entering the pump. Barrier liquids are usually easier to seal than pumped liquids and/or cause less harm when leaking. 4 Design
4.1 General
4.1.7 Characteristic curve
GB/T5656---94
The characteristic curve should indicate the allowable operating range of the pump. The pump should preferably have a stable characteristic curve. The characteristic curves of the maximum and minimum impeller diameters of the pump should also be drawn as a function of the flow rate on the pump performance spectrum. 4.1.2 NPSH
Unless otherwise agreed, the required NPSH (NPSH) r shall be based on cold water as specified in GB3216. The (NPSH) r curve shall be given for water as a function of flow rate. If the pump manufacturer considers that a larger NPSH is required due to the material of construction and the pumped liquid, this shall be stated in the tender and the applicable curve shall be provided. The available NPSH (NPSH) a shall be at least 0.5 m greater than (NPSH) r. The correction factor for hydrocarbon liquids is not considered. For NPSH margin tests, see 6.3.2.3. 4.1.3 Outdoor installation
The pump shall be suitable for outdoor installation under normal environmental conditions. If the pump is required to be suitable for abnormal local environmental conditions, such as high or low temperatures, corrosive environments, sandstorms, etc., the purchaser shall specify this requirement. 4.2 Prime mover
The following points must be considered when determining the rated performance of the driver: the purpose and working mode of the pump. For example, in the case of parallel operation, attention must be paid to the possible performance range of only one pump when operating under consideration of the system characteristic curve; the position of the operating point on the pump performance curve; the friction loss of the shaft seal, the circulating liquid flow of the mechanical seal (especially for small flow pumps); the properties of the pumped liquid (viscosity, solid content, density); the power loss and slip loss of the transmission; the atmospheric conditions at the pump site. The prime mover suitable as the driver of any pump covered by this standard shall have a rated output power ratio to the rated shaft power of the pump at least equal to the percentage given in Figure 2, and the rated output power value shall never be less than 1 kW. 150
健慕售
Figure 2 Prime mover output power expressed as a percentage of the pump shaft power under rated conditions If it appears that this would make the driver unnecessarily too large, an alternative proposal should be submitted to the purchaser for approval. 22
Pump shaft power at rated conditions
4.3 Critical speed, balance and vibration
4.3.1 Critical speed
GB/T 5656-94
Under operating conditions, the actual first lateral critical speed of the rotor when connected to the agreed driver shall be at least 10% higher than the highest permissible continuous speed including the turbine driven pump's self-stop speed. 4.3.2 Balance and vibration
The rotating parts of the pump shall be balanced. When measured on the manufacturer's test equipment, the vibration values shall not exceed the vibration severity limits specified in Table 1. These values are measured radially on the bearing housing at a single operating point at rated speed (±5%) and rated flow (±5%) in the non-cavitation operating state.
For reference, this requirement can usually be achieved if the balance is carried out according to GB9239 G6.3 level. Table 1 Vibration severity limit of multi-blade impeller horizontal centrifugal pump 1 rpm
≤1800
1800225mm
For special impeller pumps, such as single-channel impeller pumps, the limit values specified in Table 1 may be exceeded. In this case, the pump manufacturer should state this in its supply.
The relationship between amplitude and vibration frequency is shown in Appendix B (reference). 4.4 Pressure-bearing parts
4.4.1 Pressure-temperature characteristics
The manufacturer should clearly specify the ultimate pressure of the pump under the worst working conditions (rated pressure). In any case, the rated pressure of the pump (pump body and pump cover, including shaft seal box and packing gland/sealing end cover) shall not exceed the nominal pressure of the pump flange. If the pump is made of cast iron, ductile iron, carbon steel or stainless steel, its basic design pressure at 20°C should be at least 1.6MPa gauge pressure.
For materials whose tensile strength requirements do not allow the 1.6MPa level, their pressure-temperature characteristics should be corrected according to the stress-temperature characteristics of the material, and the manufacturer should clearly state this. 4.4.2 Wall thickness
The pump body, including the shaft seal box and the gland or sealing end cover, shall have an appropriate wall thickness to withstand the pressure and limit deformation under the conditions of operating temperature and rated pressure.
The pump body shall also be suitable for the pressure of the hydrostatic test at ambient temperature. Unless otherwise agreed, pressure-containing parts shall have a corrosion allowance of 3 mm. 4.4.3 Materials
The materials used for pressure-containing parts shall depend on the pumped liquid and the purpose of the pump (see Chapter 5): 4.4.4 Mechanical properties
4.4.4.1 Disassembly
The pump should preferably be designed as a rear-opening structure so that the impeller, shaft, shaft seal and bearing components can be removed without disturbing the inlet and outlet flange connections. Provision should be made to facilitate the separation of the components, such as the provision of jacking screws. 4.4.4.2 Jacking screws
When a jacking screw is provided as a means of separating the contact surfaces, if the engagement may cause leakage or poor fit of the joint surface, a flat bottom hole shall be machined into the mating surface to accommodate the jacking screw. Hollow head screws shall be avoided if possible. 4.4.4.3 Water and steam jackets
GB/T5656--94
The water and steam jackets used for heating or cooling the pump body or stuffing box (or both) are of free choice of design. The water jacket shall be suitable for cooling needs under conditions of temperature of 170°C and working pressure of at least 0.6MPa. 4.4.4.4 Pump body gaskets
The design of the pump body gaskets shall be suitable for use under rated working conditions and water pressure test conditions at ambient temperature. The body-cover gasket shall be restricted on the atmospheric side to prevent the gasket from popping out suddenly. 4.4.4.5 Discharge of steam
Pumps conveying liquids at pressures close to their vapor pressure or liquids containing gases shall be designed to completely discharge the steam. 4.4.4.6 External bolted connections
The diameter of the bolts or studs connecting the pressure body, cover and other parts including the shaft seal box shall be at least 12 mm. Note: If 12 mm bolts or studs are not possible due to space limitations, smaller diameters may be used. The bolted connections (performance level) selected shall be suitable for the rated pump pressure and the conventional tightening methods. If a fastener of a special quality must be used at a certain location, the interchangeable fasteners used in the remaining connection locations shall also be of the same quality. The use of hollow head screws should be avoided if possible.
4.4.4.7 High temperature pump support
For high temperature applications, such as above 175°C, due consideration must be given to the support of the pump along the centerline. 4.5 Nipples (nozzles) and other miscellaneous pipe connections Note: For the purpose of this standard, nipples and nozzles are synonymous. 4.5.1 Scope
This section deals with the provisions for various fluid pipe connections connected to the pump, whether they are for operating or maintenance use. 4.5.2 Inlet and outlet nipples
The inlet and outlet nipples shall be flanged and designed for the same pressure, unless the pump manufacturer states otherwise and emphasizes the need for pressure reduction.
4.5.3 Bleed, pressure gauge and drain connections
Bleed devices shall be provided in all areas of the pump body and seal chamber, unless the pump is made self-bleeding by the arrangement of nipples. It shall be possible to connect a pressure gauge at the inlet and outlet nipples. The connections are not drilled. If these connections require drilling, this shall be stated on the enquiry and/or order.
Drain connections shall be provided at the lowest point or points of the pump. If these connections require drilling and the installation of screw plugs or other sealing materials, this shall be stated in the enquiry and/or order. 4.5.4 Closing parts
The material of the sealing parts (screw plugs, blind flanges, etc.) shall be suitable for the pumped liquid and attention shall be paid to whether the material combination is suitable for corrosion resistance and to minimize the risk of galling and seizure of the threads. All openings in contact with the pressurized pumped liquid, including the holes at the shaft seal, shall be equipped with removable sealing parts sufficient to withstand the pressure. 4.5.5 Auxiliary pipeline connections
All auxiliary pipeline connections shall be of material, size and thickness that meet the requirements of the intended function (see also 4.13.5). The internal diameter of the pipe fittings shall always be at least 8 mm and the wall thickness shall be at least 1 mm. Pipe fittings with larger diameters and wall thicknesses are preferred. Auxiliary pipelines shall be equipped with removable joints to facilitate disassembly. The type of connection shall be determined by agreement. 4.5.6 Identification of connections
All connections shall be identified on the installation drawing according to their function and role. It is recommended that this identification also be applied to the pump. 4.6 External forces and moments acting on flanges (inlet and outlet) If no other method is agreed between the purchaser and the manufacturer, the method given in Appendix C (test parts) shall be used for cast steel pumps. The purchaser shall calculate the forces and moments acting on the pump by the piping system. The manufacturer shall verify that these loads are acceptable for the pump under investigation. If the loads are higher than the permissible values, the purchaser and the manufacturer shall agree on a solution to the problem. 4.7 Short pipe flange
GB/T 5656-94
The dimensions of the outer contour of the flange shall be such that it is possible to match the flange according to GB4216 and GB9112. If the standard type of the pump manufacturer requires a flange thickness and diameter greater than the specified grade, heavier flanges may be supplied, but the surface processing and drilling of the flanges shall still be carried out in accordance with the regulations. Ensure that the bolt heads and/or nuts on the back of the cast iron flange are well seated. The bolt holes should be arranged across the center line. 4.8 Impeller
4.8.1 Impeller design
Depending on the application, the impeller can be of closed, semi-open or open construction. Cast or welded impellers should be of single-piece construction, except for the sealing ring. In special cases, i.e. when the impeller outlet width is very narrow or the impeller material is special, other methods of manufacturing the impeller are allowed, but this requires the consent of the purchaser.
4.8.2 Impeller fixing
The impeller should be reliably fixed to prevent circumferential and axial movement when rotating in the specified direction. 4.8.3 Axial adjustment
If the axial clearance needs to be adjusted on site, an external adjustment device should be provided. If the adjustment is achieved by axial displacement of the rotor, it must be noted that it may have a dangerous effect on the mechanical seal. 4.9 Sealing rings or equivalent components
Sealing rings shall be provided where appropriate and shall be replaceable and securely locked against rotation. 4.10 Running clearances
When establishing running clearances between stationary and moving parts, the operating conditions and the properties of the materials used for these parts (such as hardness and resistance to abrasion) shall be taken into account. The clearances shall be of such size as to prevent contact with each other. The material combination shall be chosen to minimize the risk of wear and seizure. 4.11 Shafts and bushings
4.11.1 General
Shafts shall be of sufficient size and rigidity to: a.
transmit the rated power of the prime mover;
minimize the degree of poor working condition of packing or seals; b.
minimize the risk of seizure and wear; c.
give due consideration to static and dynamic radial loads, critical speeds (see 4.3.1) and starting methods and related inertia loads. d.
4.11.2 Surface roughness
Unless otherwise required for sealing, the roughness of the shaft and sleeve surfaces at the stuffing box, mechanical seal and oil seal shall not exceed 0.8um. The surface roughness measurement shall be carried out in accordance with GB6062. 4.71.3 Shaft deflection
The calculated shaft deflection caused by the radial load generated during the operation of the pump at the radial plane passing through the outer end face of the stuffing box shall meet the requirements for normal operation of the mechanical seal. For pumps of GB5662, as confirmed by the prototype test, this value shall not exceed 50m. Among the following conditions a is always applicable, and the other conditions b and/or c may require agreement to apply: a. Within the allowable operating range of the pump;
b. Under the design load,
Under the maximum load.
When determining the shaft deflection, the supporting effect of the packing should not be considered. 4.11.4 Diameter
If practicable, the diameter of the part of the shaft or sleeve in contact with the shaft seal shall comply with the provisions of GB5661. 4.11.5 Radial runout of the shaft
The manufacture and assembly of the shaft and sleeve (if installed) shall ensure that the radial runout (see 3.16) at the radial plane passing through the outer end face of the stuffing box is not greater than 50 μm for a nominal outer diameter less than 50 mm; not greater than 80 μm for a nominal outer diameter of 50~100 mm; and not greater than 100 μm for a nominal outer diameter greater than 100 mm. 2.
4.11.6 Axial displacement
GB/T5656-94
The axial displacement of the rotor allowed by the bearing shall not have a harmful effect on the performance of the mechanical seal. 4.11.7 Fixing and sealing of the sleeve
If a sleeve is installed, it shall be reliably fixed to prevent movement in the circumferential direction and axial direction. The sleeve should be close to the impeller hub, maintaining the seal and preventing the shaft from being wetted.
4.11.8 The configuration of the sleeve (if installed) on the pump with packing, the end of the sleeve component (if installed) should extend beyond the outer end face of the packing gland. On the pump with mechanical seal, the sleeve should extend beyond the seal end cover. On the pump using the auxiliary seal throttling bushing, the sleeve should extend beyond the seal end cover. In this way, the leakage between the shaft and the sleeve will not be confused with the leakage through the packing or mechanical seal end face. For some mechanical seal configurations (such as external mechanical seals, double mechanical seals), the situation may be different. 4.11.9 Fixing of thrust bearings
The fixing ring in direct contact with the bearing shall not be used to transmit the thrust from the shaft to the inner ring of the thrust bearing. It is best to use a locking nut and a retaining washer.
4.12 Bearings
4.12.1 General
Rolling bearings of standard design are usually used. However, other types of bearings may also be used. 4.12.2 Rolling bearing life
Rolling bearings shall be selected and calculated in accordance with GB4662 and GB6391. When the pump is operating within the permissible operating range, the basic rated life (B10) of the bearing shall be at least 17500h. The manufacturer shall specify the limit value of the inlet pressure under maximum load (function of the pump head) to achieve a calculated bearing life of at least 17500h.
4.12.3 Bearing temperature
In order to keep the bearing temperature within the limit range given by the bearing manufacturer, the manufacturer shall specify whether cooling or heating measures are required.
4.12.4 Lubrication
The instruction manual shall describe the type of lubricant to be used and the number of times it should be used. 4.12.5 Bearing housing design
To prevent loss and contamination, gaskets or threaded joints shall not be used to isolate lubricants from cooling or heating fluids. All openings in the bearing housing shall be designed to prevent the ingress of dirt and the loss of lubricants under normal operating conditions. In hazardous areas, any device used to seal the bearing housing shall not be designed to be a source of fire. When using thin oil lubrication, an oil drain hole with a stacked screw plug shall be provided. If the bearing housing also serves as a lubricating oil chamber, an oil level gauge or oil level constant oil cup shall be used. The markings of the recommended oil level or oil level mark positioning line shall be clearly recognizable and permanent, and shall indicate whether the oil level is static or dynamic.
If regreasable bearings are used, grease overflow facilities shall be provided. 4.13 Shaft seal
4.13.1 General
The design should be such that the following shaft seal options can be used as specified in the Appendix (reference):- soft packing (P),
single end mechanical seal (S);
double end mechanical seal (D).
Appendix D also specifies a backstop (Q), which may be necessary in some cases. The dimensions of the seal chamber should comply with the provisions of GB5661, unless the working conditions require otherwise. There should be a device to contain, collect and discharge all liquid leaking from the seal area. 26
4.13.2 Stuffing box
GB/T5656-94
The structural design should take into account the installation of packing rings. If an outlet pipe is required, the party or manufacturer should make provisions. Sufficient space should be left so that the packing can be replaced without moving or removing any parts other than the packing gland or protective device. Even if the packing loses its compressibility, the gland assembly must be kept absolutely stationary. 4.13.3 Mechanical seals
4.13.3.1 Criteria for selecting working conditions for seals The basic working condition criteria for selecting mechanical seals are: the type of pumped liquid and the chemical and physical properties; - the expected maximum and minimum sealing pressures; - the temperature and vapor pressure of the sealing liquid; - special working conditions (including starting, shut-down, thermal and mechanical shock, etc.); - the speed and direction of the pump.
4.13.3.2 Type and configuration
This standard does not involve the design of mechanical seal parts, but these parts must be suitable for withstanding the working conditions specified in the data sheet (see Appendix A).
The configuration should be specified in the data sheet (see Appendix A) (e.g. single-end, double-end, balanced or unbalanced mechanical seals, see Appendix D).
If the pump is to deliver liquids at temperatures close to their boiling point, the pressure in the mechanical seal chamber must be sufficiently higher than the pump inlet pressure, or the temperature of the area close to the seal surface must be sufficiently lower than the vaporization temperature to prevent vaporization of the liquid at the seal surface. If a back-to-back seal arrangement is used, the barrier liquid in the middle of the seal should be compatible with the process liquid and its pressure should be higher than the seal pressure.
If a back-to-back mechanical seal is installed, the stationary ring on the impeller side should be securely fixed so that it will not move due to the pressure drop of the barrier liquid.
For pumps operating at temperatures below 0°C, a containment device can be provided to prevent freezing. 4.13.3.3 Materials
Suitable materials for mechanical seal components should be selected to withstand corrosion, abrasion, erosion, temperature, thermal stress and mechanical stress. For mechanical seals, metal parts wetted by the pumped liquid should have a material quality at least equal to that of the pump body (see Chapter 5) in terms of mechanical properties and corrosion resistance.
4.13.3.4 Structural features
Concentration of the seal cover relative to the seal chamber bore shall be ensured. Locating fits based on the inside or outside diameter are the preferred method of achieving this requirement.
The seal cover shall be sufficiently flexible to avoid deformation. The seal chamber and seal cover, including the fastening bolts (see 4.4.4.6), shall be designed based on the allowable working pressure at the operating temperature and the required gasket installation load. The gasket periphery between the seal box and the static seal ring or seal cover shall be restricted or equivalent design measures shall be taken to prevent the gasket from suddenly popping out.
All static sealing elements, including the seal cover, shall be protected from accidental contact with the shaft or sleeve and from rotation. If any static sealing element contacts the shaft or sleeve, the surface in contact with the seal shall be of sufficient hardness and corrosion resistance. The shaft or sleeve shall be provided with a lead-in end and sharp edges shall be removed to prevent damage to the seal during assembly. The machining tolerances of the sealing chamber and the sealing end cover shall be such that the end face runout of the mechanical seal at the static seal is not greater than the maximum permissible value specified by the seal manufacturer.
If a throttling bushing is provided in the sealing end cover to minimize leakage in the event of a complete seal failure, the diametrical clearance in millimeters between the bushing and the shaft shall be as small as possible, but never greater than: shaft diameter/100 + 0.2. If leakage must be avoided, an auxiliary seal (e.g. double seal) shall be provided (see Appendix D) 27
GB/T 5656—94
Whenever practicable, the sealing chamber shall be designed to prevent air from being trapped. If this is not possible, the sealing chamber shall be manually vented by the operator and its operation method shall be described in the instruction manual. The point where the liquid enters the sealing chamber and, if necessary, flows out of the sealing chamber shall be as close to the sealing surface as possible. If not otherwise agreed, the holes in the seal chamber may be drilled and tapped even if no joints are required (see 4.5.3 and 4.5.5).
4.13.3.5 Assembly and testing
Assembly for shipment see 7.1.
The hydrostatic test pressure of the mechanical seal shall not exceed the ultimate sealing pressure. If the sealing surface is not suitable for service with water as the medium (initial service condition), this fact shall be notified to the purchaser before ordering. 4.13.4 Auxiliary piping systems for stuffing boxes and mechanical seals 4.13.4.1 The pump shall be designed to accept auxiliary piping such as may be required for the shaft seal to meet the specified conditions. 4.13.4.2 Auxiliary piping systems may be required in the following situations: a. Such piping involves process liquids or liquids that can enter the process: - circulation, if not through internal passages; - injection (flushing);
- barrier;
- sealing;
b. The liquid and steam supplied by this type of pipeline do not enter the process: 1 heating:
1 cooling,
— withdrawal.
4.13.5 Mechanical design of auxiliary piping
Auxiliary piping shall be arranged in accordance with Annex E (informative) or another arrangement agreed upon. In all cases the purchaser and the manufacturer shall agree on the details and scope of supply of service piping connections for external liquid and steam supply.
If specified, the piping system, including all accessories, shall be supplied by the pump manufacturer and, if possible, shall be fully mounted on the pump.
The piping system shall be designed and arranged so that it can be removed for cleaning and maintenance and shall be adequately supported to prevent damage due to vibration during normal operation and maintenance activities.
The temperature and pressure rating of auxiliary piping conveying process liquids (see 4.13.4.2a) shall not be lower than the temperature and pressure rating of the pump body (see 6.3). The piping material shall be resistant to corrosion caused by the conveyed liquid (see 4.5.5) and environmental conditions. The service piping for liquid and steam supply (see 4.13.4.2b) shall be designed according to the pressure and temperature ratings (see 4.4.4.3) of the corresponding liquid and steam supply design.
Drain holes and leakage liquid outlets shall be provided at each low point to completely drain the liquid. The piping shall be designed to avoid the formation of air pockets. The service piping for steam supply shall be "top inlet and bottom outlet", and other service piping shall generally be "bottom inlet or side inlet, top outlet". If a throttling orifice is installed, its diameter shall preferably not be less than 3 mm. When an adjustable orifice is used, the minimum continuous flow rate shall be guaranteed. 4.14 Nameplate
The nameplate shall be made of corrosion-resistant material suitable for the environmental conditions and shall be firmly fixed to the pump. The required information on the nameplate shall include at least the name (or trademark), the address of the manufacturer or supplier, the pump identification number (such as serial number or product number), model and size. The remaining space can be used to give additional information about flow, pump head, pump speed, impeller diameter (maximum and actually installed), pump rated pressure and temperature. 4.15 Steering
GB/T5656-94
The direction of rotation should be indicated by an arrow provided on a solid protrusion. 4.16 Coupling
The pump should generally be connected to the driver through an elastic coupling. The size of the coupling should meet the maximum torque requirements of the predetermined driver. The limiting speed of the coupling should be consistent with all possible operating speeds of the predetermined pump driver. An extension coupling should be provided so that the pump rotor can be removed without moving the driver. The length of the extension section of the coupling depends on the distance between the two shaft ends required to remove the pump. If possible, the distance between the shaft ends should be in accordance with national standards (such as GB5662). If the driver does not have a thrust bearing, it may be necessary to apply a limited end floating coupling. The two halves of the coupling should be effectively tightened to prevent movement relative to the shaft in the circumferential direction and axial direction. The shaft ends may have threaded center holes to enable the coupling to be assembled correctly.
If the components of the coupling are balanced together, the correct assembly position shall be indicated by permanent and clearly visible markings. The permissible radial, axial and angular displacement deviations of operation shall not exceed the limits specified by the coupling manufacturer. When selecting the coupling, various operating conditions such as temperature, torque changes, number of starts, pipeline loads, and the rigidity of the pump and the base shall be considered. Appropriate coupling guards designed in accordance with national safety regulations shall be equipped. If the pump is delivered without a drive system, the pump manufacturer and the purchaser shall reach a common agreement on the selection of the following parts: a.
Drive system: type, power, size, weight, mounting method; coupling: type, manufacturer, size, processing, shaft hole and keyway, coupling guard; b.
Speed range and pump shaft power.
4.17 Foundation
The dimensions of the foundation shall preferably be in accordance with those specified in GB5660 (Common foundation for pump and motor). If a foundation other than that specified in GB5660 is used for a pump conforming to GB5662, agreement shall be obtained. The foundation shall be designed to withstand the forces on the pump stub given in 4.6 without causing shaft misalignment exceeding that given in Appendix C.
The material of the foundation (e.g. cast iron, composite structural steel, concrete) and the method of installation (with or without grouting) shall be agreed between the purchaser and the manufacturer.
The foundation may or may not require grouting. 4.17.1 Ungrouted foundation
Ungrouted foundations shall be rigid enough to withstand the loads of the pump when it is free-standing or bolted to an ungrouted foundation as described in 4.6.
4.17.2 Grouted foundationsbZxz.net
Foundations requiring grouted foundations shall be designed to ensure good grouting (e.g. air entrapment shall be prevented). If grouting holes are necessary, their diameter shall not be less than 100 mm or an area equivalent thereto. Grouting holes located in the drainage area shall have raised edges.
4.17.3 Design of the base
Where necessary, the base shall be provided with means for collecting and draining leaking liquids. The drainage area shall be inclined towards the discharge outlet at a slope of at least 1:100.
The pipe connection for draining liquids shall have a thread diameter of at least 25 mm and shall be mounted on the pump end of the base. 4.17.4 Assembly of pump and driver on the base 4.17.4.1 Vertical adjustment of the driver shall be ensured to compensate for the tolerances of the pump, driver and base. Such adjustment shall be achieved by using shims or wedges with a total thickness of at least 5 mm. 4.17.4.2 If the buyer supplies the driver or coupling, the buyer shall provide the pump manufacturer with the verified installation dimensions of these parts.
If the driver is not installed by the pump manufacturer and the total requirement for gaskets and wedges exceeds 25 mm, the pump manufacturer shall provide and attach removable gaskets for adjusting the height of the shaft centerline. Unless otherwise agreed, the fixing holes for the driver shall not be drilled. 20
5 Materials
5.1 Selection of materials
GB/T 5656—94
Usually the materials are listed in the data sheet. If the material is selected by the purchaser but the pump manufacturer considers other materials to be more suitable, these materials shall be proposed by the manufacturer as alternative materials according to the working conditions specified in the data sheet. Materials for hazardous liquids shall be agreed upon by the purchaser and the manufacturer. Non-plastic materials shall not be used for pressure-bearing parts of pumps for conveying flammable liquids.
The pump manufacturer shall give due consideration to the mechanical design of the pump for high or low temperature applications (i.e. above 175°C or below -10°C). See 4.13.3.3 for sealing materials. 5.2 Material composition and quality
The chemical composition, mechanical properties, heat treatment and welding methods of the materials shall conform to the relevant material standards. If testing and verification of the above properties are required, the purchaser and the supplier shall agree on the methods of testing and verification (see Chapter 6).
5.3 Repair
Repair by welding or other methods shall be in accordance with the relevant material standards according to the category. It is prohibited to repair cracks and defects in pressure castings by plugging, hammering, painting or dipping.
6 Factory inspection and testing
6.1 General
The purchaser may request any or all of the following tests, and if so, these tests shall be specified in the data sheet (see Appendix A). These tests may be provided at an additional cost. Such tests may be visually verified or certificated. The test reading sheet for visually verified tests shall be signed by the inspector and the manufacturer's representative. The certificate shall be issued by the manufacturer's quality control department. Pressure-containing parts shall not be painted with any paint other than anti-corrosion primer before completing the test and inspection. If inspection is specified, the buyer's inspectors shall be allowed to enter the manufacturer's workshop at a time agreed upon by both parties and shall be given appropriate facilities and information to enable satisfactory inspection. 6.2 Material Tests
If required on the purchase enquiry and order, the following test certificates shall be available: 6.2.1 Chemical composition (according to the manufacturer's standard specifications or on the basis of samples from each batch of melt) 6.2.2 Mechanical properties (according to the manufacturer's standard specifications or on the basis of samples from each batch of melt and heat treatment) 6.2.3 Susceptibility to intergranular corrosion (if applicable) 6.2.4 Non-destructive tests (leakage, ultrasonic, dye penetrant, magnetic particle, X-ray photography, spectral identification, etc.) 6.3 Testing and Inspection of Pumps
6.3.1 Hydrostatic Test
6.3.1.1 The pressure-bearing parts (pump body, pump cover and sealing end cover, including their fastening parts) shall be subjected to a hydrostatic test with a test pressure of 1.5 times the basic design pressure. The test shall be carried out with cold water (minimum temperature of 15°C for testing carbon steel materials) and the pressure shall be maintained for at least 10 minutes without visible leakage. 6.3.1.2 The test pressure of the auxiliary piping of type a (see 4.13.4.2) shall be at least 1.5 times the rated pressure. When carrying out any hydraulic pressure test on the assembled pump, care must be taken not to damage the packing, mechanical seal (see 4.13.3.5) Such auxiliary fittings produce strain.
6.3.1.3 Water, steam jackets and auxiliary piping corresponding to category b (see 4.13.4.2) should be subjected to a water pressure test with a test pressure of 1.5 times their rated pressure.
6.3.2 Performance test
6.3.2.1 For test liquids other than cold water and for performance tests under different operating conditions (such as high inlet pressure), the conversion method should be 30
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