Technical Specifications for Centrifugal Pump Engineering

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Please share; the technical specifications for centrifugal pump engineering are very helpful for placing orders, as I’ve compiled them myself! Technical Specifications for Centrifugal Pump Engineering 1 General Provisions 1.1 Scope These technical specifications, together with the purchase order, purchase contract/quote, and data sheets, establish the basic requirements for the design, manufacturing, inspection, testing, and condition at delivery of medium- and light-load petroleum and chemical industry centrifugal pumps, drive units, and auxiliary equipment. The provisions of this standard apply to centrifugal pumps that meet all of the following conditions: rated discharge pressure ≤ 1.96 MPa(G); rated speed (5% additional for drive-driven pumps) ≤ 3000 r/min; medium temperature < 180°C; driver power ≤ 110 kW; rated head ≤ 120 m; maximum impeller diameter ≤ 333 mm; maximum suction pressure ≤ 0.5 MPa(G). Pumps that satisfy the above conditions mainly include those designed in accordance with the GB 5662 and GB/T 5656 standards ； Centrifugal pumps designed in accordance with ISO2858 and ISO5199 standards ； Centrifugal pumps designed in accordance with the ANSI/ASME B73.1M standard: The provisions of this specification do not apply to the following types of pumps: canned motor pumps, magnetically driven pumps, and other special pumps. 1.2 Special requirements for the project: Special requirements for the project refer to technical documents that result from modifications to the relevant provisions of these general project specifications, based on the requirements put forward by the user, the specific conditions on site, and the available engineering design data, and which are provided as attachments. When the special requirements of a project conflict with these general project regulations, the special requirements of the project shall prevail. 1.3 Standards and specifications 1.3.1 The latest versions of the following standards and specifications may form part of these requirements: GB 5662 – Marking, performance, and dimensions of axial suction centrifugal pumps (1.6 MPa); GB/T 5656 – Technical requirements for centrifugal pumps (Class II) ； IsO 2858 axial suction centrifugal pump (16bar) labeling, performance, and dimensions ； ISO 5199 Technical specifications for centrifugal pumps (Class II). ANSI or ASME B 73.1M Specification for Horizontal End-Suction Centrifugal Pumps for Chemical Service 1.3.2 Other standards and specifications specified in the data sheet may also be part of these requirements. 1.3.3 The seller must ensure that its design, manufacturing, inspection, and testing comply with the specified standards, specifications, and relevant regulatory requirements. 1.3.4 When the buyer’s data sheets/engineering specifications conflict with the requirements of the specified standards, codes, or regulations, the seller shall notify the buyer promptly. 1.3.5 When the seller cannot accept certain terms in the buyer’s data sheet or project specifications, it shall promptly inform the buyer of the deviations and proposed corrections, and obtain the buyer’s written approval. 1.4 File priority The priority of files is as follows: purchase order or inquiry form ； Data table ； These engineering technical specifications ； The standards and specifications mentioned in the order form or data sheet. 2. Design 2.1 General requirements 2.1.1 Pumps and their auxiliary equipment shall be suitable for outdoor installation and operation. 2.1.2 The pump shall have a stability characteristic curve, on which the allowable operating range of the pump is indicated. The normal operating point of the pump shall not exceed the point of optimal efficiency, and should be as far away as possible from the minimum flow rate point. 2.1.3 The seller shall ensure that the performance of the pump, including efficiency, flow rate, head, power consumption, and the required net positive suction head, meets the specified requirements. 2.1.4 The available net positive suction head NPsHa should be at least 0.5 m greater than the required net positive suction head NPsHr, without considering any correction factors for hydrocarbon liquids. 2.1.5 All components shall have a track record of successful use under similar operating conditions; prototypes or trial products shall not be used without the buyer’s consent. 2.2 Pressure-bearing parts 2.2.1 The design pressure of the pump casing shall be equal to the sum of the highest inlet pressure and the maximum pressure difference that the pump can achieve. When the highest inlet pressure is below atmospheric pressure, it shall be calculated based on atmospheric pressure. 2.2.2 For pumps operating at temperatures above 0°C, their design temperature should be determined by taking the highest temperature that may be encountered and adding 10°C to it. For pumps operating at temperatures equal to or below 0°C, their design temperature should be determined based on the lowest operating temperature that may be encountered. 2.2.3 At the operating temperature, when transporting flammable, explosive, or toxic media with a relative density of less than 0.7, pumps with a radial split structure should be used. 2.2.4 The pump should be designed with a back-door structure, allowing the impeller, shaft, shaft seal, and bearing components to be removed by moving the inlet and outlet flange connections when it is not in use. 2.3 Impeller 2.3.1 The impeller shall be a monolithic casting. 2.3.2 For a pump casing of a certain specification, it is not recommended to use the largest size impeller. 2.3.3 If necessary, an impeller seal ring should be installed. The impeller seal ring should be firmly locked and unable to rotate, but can be replaced after wear. 2.4 Operating clearances 2.4.1 The operating clearances between sealing rings and between other components shall be determined based on factors such as thermal expansion, material type, and the deflection of rotating parts. 2.4.2 When the material has a strong tendency to stick together or when transporting a medium containing suspended particles, the operating clearance should be increased appropriately. 2.5 Shaft seal 2.5.1 The type of shaft seal shall be specified in the data sheet. 2.5.2 For packing seals, when the temperature of the medium being transported is equal to or exceeds 150°C, or when the vapor pressure of the liquid at that temperature is higher than 0.069 MPa(A), a jacket or water injection should be provided outside the packing box for cooling purposes. 2.5.3 When a mechanical seal is used, a jacket or cooling interface shall be provided in the seal chamber under the following conditions: 2.5.3.1 When the temperature of the medium being transported exceeds 120°C (except for metal bellows types). 2.5.3.2 The temperature at the sealing surface of the water pump (including the boiler feed water pump) exceeds 80°C. 2.5.3..3 Sealing arrangement at the closed end. 2.5.3..4 Liquids with low flash point. 2.5.3..5 High-melting-point products (require heating). 2.5.4 The configuration of the sealing flush pipeline for mechanical seals shall be specified in the data sheet. Unless otherwise specified, the mechanical seal and auxiliary sealing fluid system shall be supplied as a complete set by the manufacturer. 2.5.5 When the sealing pressure exceeds 0.49 MPa(G), a balanced mechanical seal should be used. 2.5.6 Mechanical seals and packing seals should not be used during hydrostatic testing. 2.5.7 Seals should be installed when conducting mechanical operation tests at the manufacturer’s facility. After the test is successful, the mechanical seal should be retained, while the packing seal should be removed. 2.5.8 When a series mechanical seal is used, a throttle bushing must be provided. 2.5.9 The service life of the mechanical seal can be specified in the contract. 2.6 Bearings and Bearing Housings 2.6.1 Generally speaking, radial and thrust bearings use rolling bearings. Under rated operating conditions, the minimum calculated service life of the bearing is 17,500 hours. 2.6.2 The bearing housing shall be effectively sealed to prevent the intrusion of moisture, dust, and other contaminants. 2.6.3 The lubrication and cooling systems for bearings shall be selected according to the operating conditions, and they must ensure that the temperature of the bearing housing does not exceed 70°C under continuous operation, or 40°C above the ambient temperature – whichever is lower. 2.7 Dynamics 2.7.1 The first transverse critical speed of a rigid bearing should be at least 10% higher than the maximum operating speed. 2.7.2 The support system provided by the seller (base, frame, and bearing housing) shall not experience resonance within an operating speed range of 10% of the soil velocity. 2.8 Materials 2.8.1 The selection of materials shall be carried out by the manufacturer in accordance with the buyer’s requirements and the specified operating conditions, and confirmed accordingly. 2.8.2 If the seller confirms that the materials it provides are superior to those specified in the buyer’s data sheet, they may be used upon the buyer’s approval. 2.8.3 Pump casings used for transporting flammable or toxic media shall be made of carbon steel or low-alloy steel. 2.8.4 When the temperature of the medium being transported is ≤ –20°C, low-temperature materials must be used, and impact tests at the minimum operating temperature shall be conducted in accordance with the relevant standards. 2.8.5 Unless otherwise specified, the corrosion allowance for pressure parts made of carbon steel and low-alloy steel is 3 mm, while for pressure parts made of alloy steel and non-ferrous metal materials, the corrosion allowance is 0. 2.8.6 Pumps for transporting liquid ammonia shall not use components made of copper or copper alloys. 2.9 Nameplate and Orientation 2.9.1 The nameplate shall be made of stainless steel or Monel alloy suitable for the environmental conditions, and shall be firmly fixed to the pump body at a location where it is easily visible. 2.9.2 The nameplate shall clearly display the following information: tag number, manufacturer’s name, pump series number, date of manufacture, specifications and model, rated flow rate (m3/h), rated head (m), rated speed (r/min), hydrostatic test pressure of the pump casing, shaft power (kw), and pump weight (kg). 2.9.3 The direction of rotation shall be indicated by a sturdy and protruding arrow. 3. Auxiliary Equipment 3.1 Drive Motors and Transmission Devices 3.1.1 The ratio of the rated output power of the drive motor to the rated shaft power of the pump shall be at least equal to the percentage value given in Figure 2 on page 4 of the GB/T5656—94 standard; the rated output power must not be less than 1 kW. 3.1.2 When the turbine is used as a drive, its rated output power shall be at least 110% of the shaft power of the pump plus the transmission losses (at the pump’s rated point and under normal steam conditions). 3.1.3 The rated power of the transmission mechanism (including the gearbox) shall be at least equal to the rated output power of the drive motor. 3.2 Couplings and guards. 3.2.1 Flexible couplings are usually used. The coupling should be able to meet the requirements of transmitting the maximum torque of the drive mechanism as well as the highest rotational speeds that can be achieved. 3.2.2 Extended couplings should be provided to allow the pump rotor to be removed without moving the drive machine. 3.2.3 The manufacturer shall provide a coupling guard. If the pump operates in a hazardous area, the guard should be non-sparking. 3.3 Base 3.3.1 The base shall be a single-piece integral structure made of cast iron or welded steel; the surface intended for mounting the pump and the drive mechanism shall be mechanically processed. 3.3.2 When the pump transports flammable or toxic media, a liquid collection tray should be provided on the base to collect and drain any leaked liquids; the drainage area shall slope in the direction of the outlet at a gradient of at least 1:100. The pipe fitting for discharging liquid shall have threads with a diameter of at least 25 mm and be installed on the base at the end closest to the pump. 3.3.3 Unless otherwise specified, pumps and drives shall be mounted on a common base. 3.3.4 Unless otherwise specified, anchor bolts, nuts, washers, auxiliary piping, and accessories shall be supplied in sets by the manufacturer. 3.4 Pipeline System 3.4.1 The inlet and outlet of the pump should be connected by flanges, and the flanges at the inlet and outlet of single-stage and double-stage pumps should have the same pressure rating. 3.4.2 The pump shall have interfaces for exhaust, liquid discharge, and seal flushing, which shall be specified in the data sheet. 3.4.3 When the pump casing is made of alloy steel, the material of all components of the process fluid piping or flushing system shall be equal to or superior to that of the pump casing, and all such components shall be made of steel. 3.4.4 Unless otherwise specified, the corrosion allowance for auxiliary pipelines and equipment shall be at least 1.6 mm for carbon steel and low-alloy steel; the corrosion allowance for alloy steel or non-ferrous metals shall be zero. 3.4.5 An observation sight glass (hole) should be provided on the cooling water outlet pipeline. 3.4.6 Threaded joints in pipelines carrying toxic or flammable media shall be sealed by welding to prevent leaks. 3.5 Special Tools: The seller shall provide a set of special tools for the buyer to use during disassembly, assembly, and maintenance. 4. Inspection and Testing 4.1 General Provisions 4.1.1 The seller shall carry out inspections and tests in accordance with the inquiry letter, data sheets, the specifications for this project, and relevant standards. The inspection items shall be specified in the data sheet or contract. 4.1.2 Where specified in the contract, the seller shall provide the buyer with the following inspection and testing reports: Material inspection certificates ； Non-destructive testing report ； Dimension inspection report ； Dynamic Balance Test Report ； Performance and Mechanical Operation Test Report ； Cavitation Performance Test Report ； Other inspection and test reports. 4.2 Hydrostatic test 4.2.1 All pressure-bearing components, including the cooling jacket, shall be tested at the pressure specified in the data sheet. 4.2.2 The hydrostatic test pressure shall be 1.5 times the design pressure, and the holding time shall be at least 15 minutes. 4.3 Performance tests and operation tests 4.3.1 Unless otherwise specified, each pump shall undergo the following tests at its rated speed: 4.3.1.1 Performance tests The performance tests shall be conducted at at least three different flow rates, namely the shut-off point (or minimum flow rate point), the rated point, and 110% of the rated flow rate. 4.3.1.2 After the performance test, a running test is conducted to perform a mechanical inspection of the pump. Including performance tests, its continuous operation time is usually 1 hour. 4.3.2 At the rated speed and rated flow rate, the pump shall meet the following performance specifications ； 4.3.2.1 Nominal value of total head H, in meters; allowable deviation, %: H≤150 –2～+5; 150＜H≤300 –2～+3; H＞300 –2～+2. 4.3.2.2 Shaft power: allowable deviation is ±4%. 4.3.2.3 Efficiency, allowable deviation is -0. 4.3.2.4 Required net positive suction head; allowable deviation is ±0. 4.3.3 During testing, the reliability of the sealing components must be checked; substitute seals shall not be used. 4.3.4 For certain reasons, the pump needs to be disassembled and repaired after testing. The repaired pump shall undergo final factory testing, with the newly obtained data being used as the basis. 4.4 NPSH margin test 4.4.1 The NPSH margin test shall be conducted under the following conditions: 4.4.1.1 When NPSHa – NPSHr < 1 m. 4.4.1.2 When the properties of the liquid to be transported have specific requirements. 4.4.2 The gasoline reserve test shall include the following four different flow rates: minimum flow rate ； Medium flow rate ； Rated flow rate ； 110% of rated flow rate. 4.5 Preparation for shipment: 4.5.1 Before shipping, the buyer shall clean all components and apply appropriate anti-corrosion treatment as well as necessary protection measures, to ensure that the pump and its associated equipment can be stored at the site for at least 6 months without any damage occurring, without the need for further actions. 4.5.2 All openings with flanges must be sealed with metal blind plates, while all openings without flanges should be closed using plugs. 4.5.3 All components shall be properly packaged and secured to prevent damage during transportation. 5 Paint, Marking, Packaging, and Transportation 5.1 Paint 5.1.1 All external surfaces except those that are machined shall be coated with primer and topcoat; machined surfaces shall be coated with an anti-rust agent. 5.1.2 The inner surface of the pump shall be sprayed (coated) with an appropriate anti-rust coating. 5.1.3 Stainless steel parts do not require painting on their surface. 5.2 Marking 5.2.1 All accessories and materials shipped in bulk shall be equipped with appropriate labels or marked. 5.2.2 All removable components shall be marked with corresponding fit marks. 5.3 Packaging and Transportation 5.3.1 The packaging of the pump shall be carried out in accordance with the relevant regulations for domestic supply and export packaging. 5.3.2 Unless otherwise specified, each packing box shall have two packing lists, one inside the box and the other attached outside the box. 6. Drawings and documents 6.1 Seller’s quotation documents 6.1.1 The seller shall provide quotation documents in accordance with the buyer’s requirements and the provisions of the inquiry letter. 6.1.2 The quotation documents should generally include the following contents: factory introduction and qualification certificates ； Data tables and performance curves ； Deviations from the request for quotation or standards ； Supply scope and supply status ； Inspection and testing items ； Dimensions and port orientation ； Cross-section ； Consumption of water, electricity, and steam ； Recommended list of spare parts ； Price, validity period, and performance table. 6.2 Contract Documents 6.2.1 The purchase contract shall specify the names, number of copies, and submission deadline for the technical documents to be provided by the seller. 6.2.2 The technical documents provided by the seller should generally include the following contents (but are not limited to these): Document list ； Data tables and performance curves ； Dimensions, electrical, instrumentation, and basic conditions diagrams ； Auxiliary pipeline layout diagram and connection list ； Pump cross-section diagram with material list ； Sealed cross-section diagram with material details ； List of spare parts ； Installation, operation, maintenance, and repair instructions ； Product Inspection Certificate ； Inspection and test reports specified in the contract. 7. Performance guarantees 7.1 Performance guarantees 7.1.1 The pump must meet all the technical specifications specified in the contract documents, as well as satisfy the process requirements. 7.1.2 At the rated speed and rated flow rate, the deviations of the pump’s head, shaft power, efficiency, and required net positive suction head shall not exceed the requirements specified in this project for hydraulic testing. 7.2 Mechanical Warranty: Within 18 months from the date of delivery or within 12 months from the start of operation, if the product is damaged due to quality issues and this affects normal production, the seller shall promptly repair or replace the damaged components at no cost to the buyer (excluding normal replacement of wear and tear parts). The pump data sheet summarizes the operating conditions, performance parameters, structural features, materials, utility requirements, testing and inspection specifications, as well as the scope of supply for each pump identified by a specific tag number. It is one of the important technical documents for requesting quotes, submitting bids, and signing contracts. I. Instructions for filling out the centrifugal pump data sheet The centrifugal pump data sheet is shown in Table 3-1. Items 1 to 18 in the table specify the operating conditions of the pump, as well as the installation and site conditions, which are proposed by the process and systems engineering team in the design department. Article 7: The normal value of flow rate is the delivery volume required by the Material Street calculation, while the rated value is the material flow rate taking into account a safety factor (usually 1.1 to 1.5). Article 9: The inlet pressure is essential for selecting the pump shaft seal; generally, the seal pressure is slightly higher than the pump’s inlet pressure. Vapor pressure refers to the steam pressure of a material at the operating temperature, and it is also essential for the selection and design of shaft seals. NPsHa is the net positive suction head available of the unit, provided by the system specialist. Articles 19–24 specify the pumps to be selected by pump professionals or pump manufacturers based on operating conditions*. The minimum continuous flow rate is the higher of the minimum continuous stable flow rate and the minimum continuous heat flow rate. The former refers to the minimum flow rate at which the pump can operate properly without exceeding the standard limits for noise and vibration; this value can be found on the performance curve provided by the pump manufacturer (such data is not yet available for products from domestic pump manufacturers). The minimum continuous heat flow rate refers to the flow rate at which, when the pump operates at this low level, the increase in liquid temperature causes NPsHa to drop to equal NPsHr, at which point cavitation begins in the pump. If the minimum continuous flow rate of the pump is not available, it can be approximated as 30% to 35% of the flow rate at the pump’s highest efficiency point. The head specified in Article 20 refers to the head that the pump should achieve. The maximum head refers to the head at the highest point on the head curve of the impeller of the selected diameter; it is usually the head when the flow rate is zero, and serves as a basis for the instrumentation field in selecting pressure gauges. For pumps operating in parallel, the shut-off head is preferably 1.1 to 1.2 times the head at the rated flow rate. Article 21: NPRHr is the required net positive suction head of the fluid for an impeller of the selected diameter at rated flow. For hydrocarbons and hot water, cavitation is less likely to occur under the same NPSHa conditions than with plain water at normal temperature; however, for safety reasons, and in accordance with APl610, no reduction factor for NPSHr is applied. It is generally desired that NPsHr be at least 0.5 m lower than NPsHa across the entire flow range. Article 22: The rated efficiency refers to the efficiency at the rated flow rate; it is advisable to position the highest efficiency point of the selected impeller between the rated point and the normal flow rate point. Article 23: The rated shaft power is calculated based on data such as the rated flow rate, selected head, efficiency at the point of use, and medium density. The maximum shaft power is the maximum power that can be generated by an impeller of the selected diameter when operating at the maximum flow rate it can handle. Articles 25 to 48: The structure of the pump shall be specified according to its operating conditions, as indicated in the pump’s technical data; any blank fields shall be filled in by the pump manufacturer when providing a quote. Article 37: For the support method of the pump body, when the medium temperature exceeds 177°C, central line support should be adopted. The pump body cannot adopt an axial split design in any of the following cases: a) the medium temperature is greater than 200℃ ； b Flammable and explosive liquids with a relative density of less than 0.7 ； c Flammable and explosive liquids with a rated outlet pressure exceeding 6.9 MPa(G). Article 40: The design pressure of the pump casing refers to the maximum allowable outlet pressure specified for the pump casing at the temperature of the pump fluid. According to the pressure-temperature chart on the pump manual, determine the maximum allowable outlet pressure based on the pump material and operating temperature; this value should be greater than the maximum outlet pressure specified in Article 10. The hydrostatic test pressure is 1.5 times the design pressure. Article 47: Bearing housings with water-cooled jackets are typically used in applications where the temperature of the medium is above 120°C. Article 57: For the shaft seal pipeline, depending on the properties of the medium being transported, the process requirements, and the structure of the shaft seal, the appropriate design shall be selected from Appendix E \"Shaft Seal Pipeline Installation\" in GB3215 (General Technical Requirements for Centrifugal Pumps Used in Refineries, Chemical Industries, and Petrochemical Processes) or GB5656 (Technical Requirements for Centrifugal Pumps K), and the corresponding code shall be filled in. Article 64: The minimum required immersion depth of a submersible pump is intended to prevent air from entering the pump when the immersion depth is too low. This value is determined by the pump’s design and specified by the pump manufacturer. Article 66: The distance from the inlet to the bottom of the tank is usually 0.8 to 1 times the diameter of the inlet. Articles 72 to 76: The testing and inspection items shall be selected based on the importance of the pump’s use. For example, when (NPsHa—NPsHr)＞1m, it is not necessary to conduct cavitation performance tests. Instructions for filling out the data sheets for reciprocating pumps and metering pumps: The data sheets for reciprocating pumps and metering pumps are shown in Table 3–2. Items 1–18 in the table specify the operating conditions, installation environment, and site conditions of the pump. They are proposed by the process and systems engineers in the design department, following the same method as that used for filling out the centrifugal pump data sheet. Articles 19–26 are to be filled in by pump professionals or pump manufacturers when providing quotes. Among them, for Strategy 19, the maximum flow rate should be greater than the rated flow rate required by the process, and the maximum pressure should be greater than the rated outlet pressure required by the process. The stroke and number of reciprocations of plungers in Articles 21 and 22 are used to determine whether the reciprocating speed of the plunger is within the allowable range; this allows for a comparison of the quotes from different pump manufacturers. The lower this value, the longer the lifespan of the plunger and the packing. According to Articles 23 and 24, for flow regulation and metering pumps, the most cost-effective method of adjusting the stroke is usually adopted, while bypass regulation is more commonly used for reciprocating pumps. In chemical production, it is generally required that while the metering pump is operating, the flow rate can be adjusted continuously from 0 to 100% without shutting down the pump. Manual adjustment is the most economical option; for important applications or situations where explosion protection is required, pneumatic adjustment can be used. Electric adjustment of flow rate is also suitable for remote control or fully automatic operation systems. Pneumatic or electric control is often equipped with manual control for use in emergency situations. The metering accuracy of a metering pump is usually ±1%. Like metering pumps and centrifugal pumps, positive displacement pumps also experience cavitation, requiring the pump manufacturer to provide the NP5Hr value. The design department’s system specialists are reminded to take into account the additional pressure drop caused by pump flow pulsations when calculating NPsHa. Articles 27 to 46 contain the structural data of the pump, which are to be filled in by pump industry professionals based on the operating conditions and usage requirements of the pump; the blank fields are to be completed by the pump manufacturer as a basis for commercial pricing. Article 40: The name of the shaft seal flushing fluid shall be determined by the pump operators in accordance with process requirements. The cooling water supply pressure is also filled in by the pump operator. Articles 47 to 56 cover pump auxiliary equipment. To reduce the pulsation in the flow rate of inlet and outlet fluids in reciprocating pumps and metering pumps, buffers are usually installed at the pump’s inlet and outlet; whether to use diaphragm-type or gas-liquid contact-type buffers should be determined by the pump operator based on the properties of the process fluid. The volume of the buffer is provided by the pump manufacturer. For critical applications, pump operators should verify whether its volume meets the requirements. For large reciprocating pumps, when forced-circulation lubrication is used. The manufacturer shall submit the lubrication system data sheet specified in Article 54. Article 55: The purpose of installing a safety valve is to prevent the pump from being damaged due to its discharge pressure exceeding the maximum allowable operating pressure when the valve in the pump’s discharge line closes. The set pressure of the safety valve shall not exceed the maximum allowable operating pressure of the cylinder (provided by the pump manufacturer), nor shall it be less than 1.1 times the rated outlet pressure. A diaphragm rupture alarm device can be added to the 51 models of diaphragm metering pumps to ensure their safe operation. Articles 57 to 62 specify the materials for pump components, which are determined based on the conditions of the medium being transported. The filling method for the remaining terms is the same as that in the centrifugal pump data sheet. Instructions for filling out the rotor pump data sheet: The rotor pump data sheet is shown in Table 3–3. The filling method for items 1 to 18 in the table is the same as that for reciprocating pumps. Power refers to the maximum shaft power under specified operating conditions (including losses in the gearbox and coupling); the rated power of the motor as per Article 63 must be at least 1.1 times this value (Article 3.1.4 of API676 standard). Article 25: The type of rotary pump, such as single-screw, twin-screw, triple-screw, gear-type, or vane-type pumps, shall be selected by pump specialists, or the pump manufacturer shall provide two options in its quotation for the buyer to compare and decide. The rotor pump belongs to the category of positive-displacement pumps; to prevent overpressure in the pump body, a safety valve should also be installed. The setting pressure for the safety valve, as specified in Article 27, is determined in the same manner as for reciprocating pumps. The method for filling in the remaining fields of the data sheet can be referred to the centrifugal system data sheet.