Pump Specifications

Following calculation and consideration of alternative pumps (see Appendix I), the final pump specification is presented in Table 11.2. For full details of the pump, its drive construction, and dimensions, refer to the sections of the AJAX manufacturers catalogue and details included in Appendix I. 

The demands of this hydraulic system are best satisfied by the use of a single-stage centrifugal pump. These pumps are widely used throughout the chemical processing industry and offer several key advantages over other types as listed below  

Flow Normal Maximum Flow Normal Maximum 

Net positive suction head (kPa) 850.0 848.0 Control valve (% dynamic loss) 68. 0 

Number of stages Single/double suction Operating efficiency Vertical/horizontal mounting Rotational speed Impeller type Impeller diameter Construction materials Casing 

---

Pump specifications depend upon numerous factors but mostly on apphcation. Typically, the following factors should be considered wmle preparing a specification. 

It is not practical to declare the flow without the accompanying head requirements. For this reason, when someone asks for the pump specifications, they need to know the flow in gallons per minute and the head in feet. 

Assume a velocity, v, ft/sec consistent with Figure 2-46. Use Table 2-21 for short, direct connected connections to the vacuum pump. Base the final specifications for the line on pump specifications. Also the diameter of the line should match the inlet connection for the pump. General good practice indicates that velocities of 100 to 200 ft/sec are used, w ith 300 to 400 ft/sec being the upper limit for the rough vacuum classification. 

Haltiangadi, U. S., Diagram Speeds Up Pumps Specifications Job, Chem. Engineering, July 13, 1970, p. 114. 

SINGLE SUCTION MIXED FLOW AND AXIAL FLOW PUMPS SPECIFIC SPEED, N. = PPMv/G-M... 

For volume and volumetric flow, m3 and m3/h are used in preference to m3/s, which gives ridiculously small values in engineering calculations. Litres per second are used for small flow-rates, as this is the preferred unit for pump specifications. 

Determine the sprinkler requirements for a chemical process area within a building with an area of 100 ft by 30 ft that handles reactive solvents. Determine the number of sprinkler spray nozzles and pump specifications. Assume 0.5-in orifice sprinklers with 35 psig at each nozzle, giving 34 gpm each, a 10-psig frictional loss within the system, and a 15-ft elevation of the sprinkler system above the pump. 

Determine the sprinkler requirements for a chemical process area 150 ft by 150 ft. Determine the number of sprinkler heads and the pump specifications for this system (HP and gpm). Assume that the friction loss from the last sprinkler head to the pump is 50 psi and that the nozzles (0.5-in orifice) are at 75 psig. 

The pumps specifically designed for HPLC are able to provide constant flow of the mobile phase against column pressure up to 10,000 psi. However, it is important to recognize that most HPLC separations are run at pressures lower than 6,000 psi. A comparison of various pumps used for HPLC is given in Table 15.3. 

Our goal is the rational design of molecules that have a specific set of properties, generally including efficient emissions, long luminescence t s, simple optical pumping, specific environmental sensitivity, and chemical and photochemical inertness. Unfortunately, some of these aims are mutually antagonistic. 

Case Study — Bleaching-Column Feed Pump Specification... 

In order to specify a pump to meet the required operating conditions it is necessary to calculate the forces opposing the pumping of this fluid, i.e. the pressure or head which makes pumping necessary. Calculations were performed for normal flow conditions and also for design conditions 20% above the normal. The pump specification is based on the larger design values. 

Full details of the pump design calculations and the choices in pump specifications are included in Appendix I. A summary of these calculations supporting the final pump specification is presented in Figure 11. 1 and Table 11. 1. ... 

---