Because of the difference in chemical production in the liquid to be delivered to the properties, pressure and flow rate, requests for various habits are not the same, production planning of centrifugal pump is a wide variety of types. And, according to the differences for the transportation of liquid by pumping liquid properties can be divided into water pumps, corrosion resistant pumps, oil pump and the impurity pump, etc.; in accordance with the impeller structure can be divided into open, semi open and closed type pump impeller suction method can be divided into single suction pump and double suction pump; according to the number of impeller can be divided into single-stage pump (for example: ISG vertical pipeline centrifugal pump, ISW horizontal centrifugal pump, is with coupling of centrifugal pump, IH chemical centrifugal pump, etc.) and multistage pump (for example: D type multistage centrifugal pump, DL vertical multistage centrifugal pump, GDL vertical multistage pipeline centrifugal pump CDLF vertical stainless steel multistage centrifugal pump, and so on). Various types of centrifugal pump according to its structure characteristics of each into a series, and to one or several of the Chinese phonetic alphabet as a series of code. In each series, because there are various specifications, which are attached to different letters and numbers to be different. The following types of centrifugal pump used in the chemical plant are briefly described.
1) pump (B, D type, SH type)? Whenever transporting clear water and physical and chemical properties similar to water cleaning liquid, are able to use pumps.
B type pump is named single-stage single suction cantilever centrifugal pump, the most widely used, its structure is shown in Figure 2 - 24. The pump body and the pump cover are made of cast iron. Full range of head size is 8 ~ 98m, the flow rate of 4.5 to 360m3/h.
If the pressure head is higher and the flow is not too large, can use a multi-stage pump. As Figure 2 - 25 shows, series a plurality of impeller in a shaft, an impeller from the outflow of liquid after the pump shell guide guide liquid flow changes and to convert a part of the kinetic energy into pressure energy and into a impeller, due to liquid from several impeller often bear the energy, so it can be reached a higher pressure head. Domestic multi-stage pump series code named D, known as D type centrifugal pump. Impeller series is generally 2 to 9, up to 12. Full range of head size is 14 ~ 351m, the flow rate of 10.8 to 850m3/h.
If the transport of liquid flow is larger and the required pressure head is not high, you can choose a double suction pump. Double suction pump impeller has two suction inlet, as shown in figure 2-26. Because the width of the impeller of double suction pump and the ratio of diameter increased, and there are two personnel, and thus a large amount of fluid infusion. Double suction pump series codenamed Sh, a full range of head size of 9 140m, the scale of 120 - 12 500m3/h flow.
2) resistant to corrosion pump (type F)? When the transport of acid, alkali and other corrosive liquids should be selection of corrosion-resistant pump, the pump is the most important characteristics is corrosion resistant material used in touch with the liquid pump components. A variety of materials to manufacture the corrosion resistance pump in the structure is the same, so they use F as its serial code. In the back of the F plus a letter indicates that the information code, to show differences.
Corrosion resistant pump another feature is the high sealing request. Because the filling material itself is difficult to completely solve the problem of corrosion, so F pump more choice of mechanical seal equipment. F type pump full range of head of the scale of 15 - 105m, the flow size of 2 ~ 400m3/h.
3) oil pump (Y type), the pump is called oil pump. Features of oil is flammable, explosive, and therefore a major request for the oil pump is sealed and perfect. When the delivery of more than 200 DEG C oil crystal, also request outstanding cooling of bearings and seal equipment, so these components are often equipped with cooling water jacket.
Domestic pump series code for y, single suction and double suction, single stage and multistage (2 - 6) pump, the full range of head size is 60 - 603m. Flow scale to 6.25 ~ 500m3 / h.
4) impurity pump (P)? Impurity pump for delivery of suspension and thick liquid, the series code for P, and subdivided for sewage PW pump, sand PS, mud pump PN etc.. The request of this kind of pump is not easy to be blocked impurity, wear-resistant, easy unpick and wash so it features is impeller width, leaf number less, often used in semi closed or open impeller. Some pump casing is lined with wear-resistant cast steel guard board.
In in order to facilitate the selection and pump production department and sometimes the same type of pump production series of characteristic curve, is on the verge of the same type of various types of pumps and a higher power scale corresponding to the a H - Q curve drawn in a general. Figure B is a series of 2-27 type water pump characteristic curve. Figure fan-shaped surface above the curved lines represent fundamental types, below curved lines on behalf of the impeller diameter than the basic types of smaller level of type a. If the sector three arc lines, center line arc represents the type of a, below the curved line represents the impeller diameter than the basic types of again a small level of type B.
