Pump coupling selection

First, the coupling and its selection Pump coupling commonly used flexible coupling, the purpose is to transmit power to compensate for the relative displacement of the pump shaft and the motor shaft to reduce the installation of precision coupling requirements, to ease the impact, Change the natural frequency of shaft system and avoid harmful vibration. Pump coupling type commonly used claw-type flexible coupling, flexible pin coupling and diaphragm coupling three. 1. Claw-type flexible coupling, claw-type flexible coupling, also known as flexible block coupling, the structure shown in Figure 1-3. Features are small size, light weight, simple structure, easy installation, low cost, commonly used in low power and not important occasions. Claw-type flexible coupling in the pump industry standard code-named Bll04, the maximum allowable torque of 850N · m, the maximum shaft diameter of 50mm. 2. Elastic Pin Coupling Elastic pin coupling is connected to the flange of two coupling halves by a pin. One end of the pin is guided by a conical surface and a nut and a tapered pin hole Form a fixed fit, the other end with a flexible sleeve, installed in the other half of the flange flange pin hole. Elastic sleeve made of rubber, the structure shown in Figure 1-4. Flexible sleeve pin coupling is a non-metallic elastic element coupling, the use of GB / T5014-2003, its simple structure, no lubrication, easy installation, easy replacement, and does not require high accuracy, commonly used in power than Small pump group. There are many domestic manufacturers. Figure 1-5 shows an elongated spring pin coupling. 3. Metal Laminated Flexible Couplings China's current production of metal laminated flexible coupling, also known as diaphragm coupling (such as JB / T9147-1999), the use of a thin thickness of the metal spring Film made of various shapes, respectively, with the main and driven shaft coupling on the two halves, as shown in Figure l-6. According to the definition of APl671, is a "disccouplin9" category. It is characterized by simple structure, no lubrication, high temperature, easy installation, easy replacement, high reliability, transmission torque. Domestic manufacturers are: Wuxi Chong Ming Transmission Engineering Limited Co., Ltd., Dandong Cloning Group Co., Ltd. 4. Pump coupling requirements, standards and operating conditions APl pump standard coupling requirements shown in Table l-7, the recommended coupling form, standard and operating conditions The coefficients are shown in Table 1-8. Pump couplings used in hazardous areas should be shielded with spark-free material such as aluminum, aluminum alloy, copper, etc. Table 1-7 API Pump Requirements for Couplings APl standard coupling requirements Metering pump APl674-1994 requirements: Couplings, couplings and shafts connected by the manufacturer standard reciprocating pump APl675 a l995 Requirements: Should be flexible coupling; if specified, the coupling , Coupling and shaft connection should be APl671 ① rotor pump APl676-1994 requirements: Flexible coupling should be used; with mechanical seal pump should be used with a countershaft (extended section) coupling centrifugal pump APl610 a 2004 requirements : Pump Speed ​​≥ 3800r / min, the IS010441 or APl671 couplings should be used; if specified, the couplings, couplings and shafts should be connected according to APl671, IS010441 or IS014691; pumps with mechanical seals should be equipped with countershaft Paragraph) of the coupling; coupling, coupling and shaft connection should be at least the maximum motor power (including the motor's operating conditions) to calculate 1.APl671 for rotating machinery does not apply to reciprocating machinery Table 1-8 Type, Standard and Operating Condition of Pump Couplings Type Recommended Type and Standard Operating Conditions K Metering Pump to Factory Standard 2.5 Reciprocating Pumps Metallic Laminated Couplings, if factory experienced, Rigid coupling may be used, but the purchaser approval, the general use of IS014691 standard 4-cylinder and above l.75 4-cylinder 2.5 the following special requirements, can be used .IS010441 standard ① The above factor multiplied by 1.25 Rotor shaft power 1.5 The power of ≥ 50kW, the use of metal laminated coupling, IS014691 standard centrifugal pump shaft power IS014691 standard 1.2 axis power ≥ 50kW, but 1.2 pump speed ≥ 3800r / min or shaft power ≥ 1000kW, the use of metal laminates Coupling, APl671 or IS010441 Standard 1.5 ①APl671 is suitable for rotary machines and does not apply to reciprocating machines, so IS010441 is recommended. 5. Determination of Coupling Specifications Calculation of coupling torque Te is calculated as follows: Tc = 9550PaK / n Where Tc - the calculated torque of the coupling, N · M; Pa-- shaft power under rated conditions, kW; K-- operating conditions, selected according to Table 1-6; n - Coupling speed, r / min. The nominal torque [Tn] of the specific specification of the coupling given in the catalog or technical data shall meet Tc≤ [Tn], n In addition, the shaft diameters of the primary and the follower shall be less than the specification Of the maximum radial dimension [D], the coupling tripping speed (trip speed) should be less than the allowable speed of the specification axial size [L]. ] Should meet the pump layout requirements. When the torque, speed and the same main and driven end of the shaft diameter is not the same, should be selected according to large shaft coupling type. 6. Hydraulic coupling Hydraulic coupling through the working fluid between the impeller and turbine energy transfer play the role of transmission of power (torque). Hydraulic coupling start smooth, with overload protection and stepless speed regulation and other functions; the disadvantage is that there is a certain power loss, transmission efficiency is generally 96% to 97%, and the price is more expensive. Hydraulic coupling has a common type, torque limit and speed control of the three basic types. Simple structure of ordinary hydraulic coupling, without any limit, speed structure measures, mainly for overload protection and speed control system, from the vibration isolation and mitigation of the impact. Limiting type fluid coupling can effectively limit the increase of transmission torque under low speed ratio and prevent overloading of driving machine and working machine. Speed ​​?? type fluid coupling is usually by changing the amount of liquid in the working chamber to adjust the output speed, the so-called volumetric adjustment, speed control fluid coupling and the ordinary type and limit the different type, it must have Working fluid external circulation system and cooling system, so that the working fluid into and out of the working chamber, to adjust the working chamber liquid volume and heat dissipation, the structure shown in Figure l-7. Pumps using speed-controlled fluid couplings are typically large pumps that require frequent changes in operating conditions or operating conditions. Such as cities, power plants water pumps, boiler feed pumps, oil pipeline pump, the refinery pressure pump and booster pump. The advantages are: the motor can be fully loaded start; the clutch can act as a clutch, overload protection; stepless speed regulation, speed range is generally 4: 1, up to 5: 1; energy saving, due to Downgrading ratio to gate valve to reduce the flow of the pump to save a lot of energy consumption.