Pumping horsepower

The handiest pump horsepower formula for a process where ... 

A rapid method to estimate pump horsepower is by the following formula ... 

Power costs for fan and pump horsepower, approximate pump efficiency for water, and any special data peculiar to the economics of the installation. This will allow the manufacturer to select a tower giving consideration to the economic factors involved. 

The economics of forced and induced draft cooling tower operation require a study of fan and water pump horsepower and usually dictate a fan static pressure requirement not to exceed 0.75-1.0 in. of water. For atmospheric and natural draft towers the economics of pumping water are still very important. This means that the ground area must be so selected as to keep the height dovm while not dropping the unit rates so low that performance becomes poor. This then, is a balance of ground area versus total deck height. Pritchard [16] presents an... 

The horsepower is established by the manufacturer by testing the various types and models. In general, the horsepower requirements will be a combination of the power to pump the liquid inside the compressor casing plus the power to compress the gas or vapor. If a recirculating seal liquid system is used, the recirculating pump horsepower is not reported as a part of the compressor requirements. 

Pump horsepower P is the power actually imparted to the fluid by the rotary pump in Equation 3-32. 

A coal slurry that is characterized as a power law fluid has a flow index of 0.4 and an apparent viscosity of 200 cP at a shear rate of 1 s-1. If the coal has a specific gravity of 2.5 and the slurry is 50% coal by weight in water, what pump horsepower will be required to transport 25 million tons of coal per year through a 36 in. ID, 1000 mi long pipeline Assume that the entrance and exit... 

What size pump (horsepower) is required to pump oil (SG = 0.85, p = 60 cP) from tank A to tank B at a rate of 2000 gpm through a 10 in. sch 40 pipeline, 500 ft long, containing 20 90° elbows, one open globe valve, and two open gate valves The oil level in tank A is 20 ft below that in tank B, and both are open to the atmosphere. 

Determine the fire water requirements (gpm, number of sprinklers, and pump horsepower) to protect an inside process area of 200 ft2. Assume that the sprinkler nozzles have a 0.5-in orifice, the nozzle pressure is 75 psig, and the rate is 50 gpm. 

To determine the change in pump efficiency for a given seal size, material and construction, a coyistant difference in horsepower should be used, not a constant decrease in points of efficiency (rj). Fig. 4 shows pump horsepower at operating conditions vs. loss of efficiency when using double mechanical seals. (Fig. 4 is to be applied to pumps that have been tested at 1,750 or 3,550 rpm.)... 

Table III shows the additional horsepower that would be added to the calculated pump horsepower that has been adjusted by two or three points for the change in speed.

There can be a significant increase in pump brake horsepower when using double mechanical seals on pumps driven by low-horsepower motors at low rpm. Depending on the type of seal and pump horsepower, the decrease in efficiency will vary from M2 to 10 points. 

The increase in horsepower required should be applied to the operating pump horsepower to calculate the resulting efficiency. This differential is greater when pump horsepower has been stepped from one speed to another by using the affinity laws (rather than by actually measuring efficiency at the speed in question). 

Power to Pump Water.—If C = cubic feet per minute, p = pressure (pounds per square inch) including static head, e = pump efficiency then horsepower = Cp 4- 230e. Taking boiler horsepower = 120C, pump horsepower boiler horsepower = p -r- 27,600e. 

The mechanical efficiency of a pump is the power utilized in percentage of the power expended. Em — Pump horsepower/Indicated horsepower. Ov Em — Pump horsepower Brake horsepower, in the case of a power pump. It accounts for all mechanical losses in transmitting the power from the power end to the pump end. Table VIII gives usual Em for various types of pumps and different lengths of stroke. 

The pump horsepower is the total work done by the pump, HPp = IIPw —... 

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