Pumps
Pipe Vibrations
To minimize pipe vibrations it is necessary to design pipe runs so that the “acoustic length” of the pipe run does not create a standing wave that adds to the pressure pulsations in the system. The acoustic length is the total overall length from endpoint to endpoint including all elbows, bends, and straight pipe runs. [...]
12Sep2009 | admin | Comments Off | ContinuedPulsation Dampeners
In many instances where the sizing recommendations previously discussed are used, there is not need to install dampeners to reduce liquidpulsations. However, in most instances, it is possible to further reduce pulsations and thus reduce pump maintenance costs and piping vibration with the use of pulsation dampeners. Dampeners are recommended for all major multipump installations, [...]
12Sep2009 | admin | Comments Off | ContinuedSuction and Discharge Piping
It is absolutely imperative that the suction piping be sized to assure that the NPSH available exceeds the NPSH required by the pump. Often, this can be arranged by elevating the suction tank or by providing a lowhead centrifugal charge pump to feed the reciprocating pump. If the NPSH available is too low, valve breakage [...]
12Sep2009 | admin | Comments Off | ContinuedCentrifugal Pump Installation Consideration
Figure 11-14 shows a typical mechanical flowsheet for two centrifugal pumps installed in parallel. It is presented to illustrate some of the considerations necessary for a good pump installation. Every installation has different objectives and very few will be exactly like this one.
The suction piping is sized for about 2-3 ft/sec and the discharge piping [...]
Wear Rings
These are easily renewable leakage seals between the impeller or shaft and casing designed to prevent leakage from high pressure to low pressure areas. They require a difference in hardness to avoid galling, and in sandy service a flushing fluid for cleaning.
12Sep2009 | admin | Comments Off | ContinuedSeals
Seals are necessary to prevent leakage at the point where the shaft enters the pump case. The most inexpensive seal is made of packing material that acts as a pressure breakdown device. Packing must be flexible and capable of being compressed for proper operation. Packing material may be made of flexible metallic strands with graphite [...]
11Sep2009 | admin | 1 comment | ContinuedBearings
Ball bearings transmit a load from a rotating surface to a fixed surface via a series of rotating balls. They are generally inexpensive, do not require any separate lubrication system, and can be designed to be selfaligning. However, they have limited ability to handle thrust, high loads, or high speeds.
Roller bearings transmit load from a [...]