Case and impeller, front and back wear rings Not required and not available in most Wear Rings are required. Wear ring clearences, attachment designs due to the use of open impellers. Buka menu navigasi. Tutup saran Cari Cari. Pengaturan Pengguna. Lewati carousel. Karusel Sebelumnya. Karusel Berikutnya. Apa itu Scribd? Apakah menurut Anda dokumen ini bermanfaat?
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Tirta Budiawan. Speedy Gonzales Riba Riba. These single with a profitable plant personnel if allowed to leak. The operating system. If a vapor release is exposed to a spark, the vapor discussed on this problem in recent years. This load cloud may even explode or catch fires.
We BEP. If the pump operates beyond the BEP, the must also be very conscious about personal safety. Examination of the resultant the API pump must take into account the specific shaft deflection problems has indicated that the fluid properties, as well as the operating conditions. This is particularly evident in the smaller sizes that involve low-flow rates and lower specific speeds of the impeller.
As shown in Figure 1, the area of the volute increases at a rate that is proportional to the rate of discharge from the impeller, thus producing a con- stant velocity at the periphery of the impeller. This velocity energy is then changed into a pressure ener- gy by the time the fluid enters the discharge nozzle. Figure 2. Double volute case Most of the larger API pumps are produced with a double volute design to reduce these loads on high-flow and high-head units. See Figure 2.
This is accomplished by balancing the opposing out-of- balance loads from each volute. While the cost of this is a slight reduction in efficiency, it is consid- ered a small price to pay for the increased reliabili- ty that ensues. Single volute case ent configuration in a vertical inline pump design. In this arrangement with a horizontal pump, the The peculiar shape of the volute also produces suction nozzle is located at the top of the casing an uneven pressure distribution around the adjacent to the discharge nozzle, rather than on the impeller, which in turn results in an imbalance of end.
On the vertical inline design, the suction noz- the thrust loads around the impeller and at right zle is once again on the side, but now it is opposite angles to the shaft. In the ANSI design shown in Figure 3, the back cover and gasket are held against the pump casing by the bearing frame adaptor, which is most frequently supplied in cast iron. This usually results in a gap between the mating faces of the frame adaptor and the pump casing that has the Figure 3.
Typical ANSI pump potential to permit uneven torquing of the bolts. In the event of a higher- The drawback of this design is, for most of than-normal pressurization of the casing by the these pumps, that the NPSH required is often con- process system, this may cause a fracture of the siderably greater than it would be in the end suction adaptor arrangement.
The adaptor is bolted indepen- dently to the back cover and does not play a part in the pressure boundary of the pump casing. Mounting Feet Another difference be- tween the two pump styles is the configuration of the mounting feet. Typical API pump ing from the underside of the casing and bolted to the baseplate.
If these pumps are used on high-temperature applications, the casing On the other hand, API pumps are mounted at will expand upwards from the mounting feet and the horizontal centerline of the casing on feet pro- cause severe thermal stresses in the casing that will jecting from each side of the casing and bolted to detrimentally affect the reliability of the pump.
This Operation at lower temperatures will not be affect- arrangement provides the API pump with the ed by this feature. As the pump comes up to vices is also evident in the bearing housings of the temperature in such cases, any expansion of the API pumps, which tend to be much more robust in metal will be above and below the casing centerline, design and also accommodate cooling jackets with and will exert minimal amounts of stress to the cas- a greater capacity of cooling water.
Materials of Construction The ability to handle higher temperature ser- Pump manufacturers can provide ANSI and API pumps in a wide assortment of mate- rials, the selection of which depends on the operating stress and effects, as well as the type of wear from the product being pumped. Repair Considerations It is important to remember, before any repair procedures are performed on any pump compo- nent, that the material of construc- tion must be accurately identified by means of the appropriate tests.
Prior to any repairs being conduct- ed on a pump casing, it is also Circle on Reader Service Card advisable to consider the economic advantage of the repair under con- sideration. Smaller and medium-sized ANSI pumps are designed with a high degree of interchangeability and produced in volume. In addition, both the indi- years in the pump industry—many of them working vidual parts and complete pumps are available fairly with both ANSI and API pump applications.
Today, quickly. API for horizontal single and multlstage pumps. Flange Rating flat faced is standard. No casing thermal growth limitations. Stainless steel is also available. Impelller materials are cast iron, carbon steel, and stainless steel. Maximum impeller diameter is about 13 inches.
Practical limit is feet. Horizontal API pumps can have as many as 14 stages. Impeller Design and Attachment Open impellers are common. Some enclosed impellers are available. No standard for attachment to the shaft. Most are threaded on the end of the shaft.
All are enclosed design. Some open designs are available for special coke crushing services.
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