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Section I I - General Information

2.10.2 Pipe Sizing Guidelines 2.10.2.1 Suction Piping

Clayton tends to follow the guidelines set forth by the Hydraulic Institute (HI) for positive displace- ment piston pumps. Equivalent pipe lengths for pipe fittings (elbows, tees, etc.) can be found in the HI refer- ence charts.

NOTE While Clayton cannot assume responsibility for the piping system into which our pump is installed, we can provide valuable guidelines for designing a piping system properly.

Suction line sizing is a major factor in the successful operation of any pump. Many pump problems result from a suction line that is too small in diameter, or too long. A properly designed piping system can prevent problems, such as: • Fluid flashing—Entrained fluid gases effuse when pressure in piping or pump falls below fluid vapor pressure. • Cavitation—Free gases in a fluid being forced back into the fluid. These implosions cause severe pressure spikes that pit and damage pump internal parts. • Piping vibration—This can result from improper piping support, cavitation, or normal reciprocat- ing pump hydraulic pulses. • Noisy operation—Most present when pump is cavitating. • Reduced capacity—Can result from fluid flashing. If it is, this is an indication that the pumping chambers are filling up with gases or vapors. These problems can reduce a pump’s life and are a potential hazard to associated equipment and per- sonnel. It is possible to fracture piping and damage the pump components with high pressure surges occur- ring when fluid is flashing or cavitating. Suction piping must be a minimum of one size larger than the pump suction connection. The actual line sizes will depend on meeting flow velocity maximums (see Figure 2-8 and 2-9 on pages 2-19 and 2-20, respectively), acceleration head calculations (see paragraph 2.11.3), and NPSH requirements (see Table 2-4 on page 2-25). 2.10.2.2 Discharge Piping Normally, discharge pipe sizing is not an issue for a standard Clayton generator installation. But, when floor space is limited at the installation site, Clayton’s close-coupled reciprocating PD pump will require relocating from its originally-designed location. In these cases, certain precautionary changes must be made to the pipe runs between the reciprocating PD pump and the heating coil inlet. Clayton recommends contacting a factory engineer to discuss any piping changes and obtain the generator’s necessary feedwater pressure requirement.

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08/11/2016

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