YCB gear pump selection principle and specific operation mode I. Understand the selection principle of YCB gear pump 1. Make the type and performance of the selected YCB gear pump conform to the device flow, head, pressure, temperature, cavitation flow, suction stroke, etc. Process parameter requirements. 2, must meet the requirements of the media characteristics. YCB gear pump selection principle and specific operation mode I. Understand the selection principle of YCB gear pump 1. Make the type and performance of the selected YCB gear pump conform to the device flow, head, pressure, temperature, cavitation flow, suction stroke, etc. Process parameter requirements. Acoustic Panels Sound Proof Padding Wall Eco-Friendly Acoustic Slat Wood Wall Panel Polyester Acoustic Slat Panel Wood Pet Wood Polyester Slat Linyi Hmbyan International Trading Co.,Ltd , https://www.lhialuminumcomposite.com
2, must meet the requirements of the media characteristics.
For pumps that transport flammable, explosive, toxic or valuable media, shaft seals are required or leak-free pumps are required.
For pumps that transport corrosive media, corrosive materials are required for convection components.
For pumps containing solid particulate media, it is required that the convection component be made of wear-resistant material, and if necessary, the shaft seal should be flushed with a cleaning liquid.
3. High mechanical reliability, low noise and low vibration.
4. The economic consideration should be based on the lowest total cost of equipment, operating, maintenance and management fees.
5. The gear pump has the characteristics of high speed, small volume, light weight, high efficiency, large flow, simple structure, no pulsation of infusion, stable performance, easy operation and convenient maintenance.
Therefore, in addition to the following conditions, the centrifugal pump should be used as much as possible:
a. When there are measurement requirements, the metering pump b is selected, the head requirement is very high, the flow rate is very small, and there is no suitable small flow rate. The high lift centrifugal pump can be used. Botaibang can use the reciprocating pump. If the cavitation requirement is not high, it can also be used. Vortex pump.
c, the head is very low, when the flow is very large, the axial flow pump and the mixed flow pump can be selected.
d. When the viscosity of the medium is large (greater than 650~1000mm2/s), consider the choice of rotor pump or reciprocating pump (gear pump, screw pump)
e. When the medium contains 75% gas, the flow rate is small and the viscosity is less than 37.4mm2/s, a vortex pump can be selected.
f. For occasions with frequent start-up or inconvenient pumping, pumps with self-priming performance, such as self-priming pumps, should be used.
Second, know the basic selection of pump selection according to the pump selection basis, according to the process flow, to the oil discharge requirements, from five aspects, not only liquid delivery, device head, liquid properties, pipeline layout and operating conditions, etc. .
1. Flow rate is one of the important performance data of pump selection, which is directly related to the production capacity and conveying capacity of the entire device. For example, the normal, minimum and maximum flow rates of the pump can be calculated in the design of the design institute. When the pump is selected, the normal flow rate is based on the maximum flow rate. When there is no maximum flow rate, 1.1 times the normal flow rate can be taken as the maximum flow rate.
2. The head required for the system is another important performance data of the pump. Generally, it should be selected by amplifying the 5%-10% balance.
3, liquid properties, including liquid media name, physical properties, chemical properties and other properties, physical properties are temperature c density d, viscosity u, solid particle diameter and gas content in the medium, etc., which involves the lift of the system, effective gas Calculation of the amount of eclipse and the type of suitable pump: chemical properties, gear pump mainly refers to the chemical corrosiveness and toxicity of the liquid medium, is an important basis for the selection of the pump material and the type of shaft seal.
4. The pipeline layout conditions of the installation system refer to the liquid feeding height, the liquid feeding distance, the suction side, the lowest liquid level, the discharge side, the highest liquid level, and other data and pipe specifications and their length, material, pipe fittings specifications, quantity. Etc., in order to carry out the calculation of the combing process and the checking of the NPSH.
5. There are many operating conditions, such as liquid operation T saturated steam force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, ambient temperature operation is gap or continuous, pump position is fixed Still removable.
Third, the specific operation of the pump selection according to the pump selection principle and selection of basic conditions, the specific operation is as follows:
1. According to the arrangement of the device, terrain conditions, oil level conditions and operating conditions, determine the choice of horizontal, vertical and other types of pumps (liquid, self-priming, gear, etc.).
2. According to the nature of the liquid medium, determine the oil pump, chemical pump or corrosion-resistant pump or impurity pump, or use a non-blocking pump.
Pumps installed in the explosion area should be equipped with corresponding explosion-proof motors according to the explosion area.
3, according to the flow size, determine the choice of suction pump or double suction pump; according to the height of the lift, choose a single-stage pump or a multi-stage pump, high-speed pump or low-speed pump (air-conditioning pump), multi-stage pump efficiency is lower than single-stage pump, such as When the single-stage pump and the multi-stage pump are also available, the single-stage pump is first used.
4. Determine the specific model of the pump. After determining which series of pumps to use, you can press the maximum flow rate. (In the absence of the maximum flow rate, you can usually take 1.1 times of the normal flow rate as the maximum flow rate.) After taking the 5%-10% balance. The main parameters of the two performances of the head are determined on the type spectrum or series characteristic curve. The operation is as follows:
Using the pump characteristic curve, find the required flow value on the abscissa, find the required lift value on the ordinate, and draw the vertical or oil level from the two values ​​up and to the right respectively. The intersection of the two lines falls on the characteristic curve. , the pump is the pump to be selected, but this ideal situation is generally rare, usually encounter the following two situations:
The first type: the intersection point is above the characteristic curve, which means that the flow meets the requirements, but the lift is not enough. At this time, if the lift phase is similar, or the difference is about 5%, it can still be used. If the lift difference is much different, select the pump with larger lift. . Or try to reduce the loss of pipeline resistance.
The second type: the intersection point is below the characteristic curve. In the fan-shaped trapezoidal range of the pump characteristic curve, the model is preliminarily determined, and then the diameter of the impeller is determined according to the difference of the lift stroke. If the head difference is small, the cutting is not performed. If the heads differ greatly, the impeller diameter will be cut according to the required ns and cutting formula according to the required Q and H. If the intersection point does not fall within the fan-shaped trapezoidal range, the pump with a smaller head should be selected. When selecting a pump, it is sometimes necessary to consider the production process requirements and select QH characteristic curves of different shapes.
5. After the pump model is determined, the pump corresponding to the physicochemical medium of the oil pump or the transport medium should be re-calibrated according to the performance table or performance curve of the model or sample.
6. For liquid pumps with a viscosity greater than 20mm2/s (or a density greater than 1000kg/m3), the oil test pump characteristic curve must be converted into the viscosity (or the density) performance curve, especially for the suction performance and The input power is carefully calculated or compared.
7. Determine the number of pumps and the backup rate:
For a normal operation of the pump, generally only one, because a large pump is equivalent to two small pumps working in parallel, (refer to the head, flow rate is the same), the efficiency of the large pump is higher than the small pump, so from the perspective of energy saving, choose one The Taida pump does not use two small pumps, but in the following cases, consider two pumps in parallel:
The flow is very large and one pump does not reach this flow.
For large pumps that require a 50% reserve rate, two smaller pumps can be operated, and two spares (three in total)
For some large pumps, pumps with 70% flow requirements can be operated in parallel without a backup pump. When one pump is overhauled, the other pump still carries 70% of the production.
For pumps that need to run continuously for 24 hours, three pumps should be used, one for operation, one for standby, and one for maintenance.
8. Under normal circumstances, customers can submit their “basic conditions for pump selectionâ€, and our company will select or recommend better pump products. If the design institute is designing the equipment, the model of the pump has been determined and configured according to the requirements of the design institute.
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