The concepts you need to understand centrifugal pumps 8-12

In my seminars I talk about the three magic formulas you need to know if you want to understand how centrifugal pumps function. Here they are:1.  As the velocity of a liquid increases, the pressure, ninety degrees to the flow, will decrease, and as the velocity of a liquid decreases the pressure, ninety degrees to… Continue reading The concepts you need to understand centrifugal pumps 8-12

Pump shaft radial thrust alternative calculations (in Imperial dimensions) 13-2.

n past papers I have given you the formulas for calculating the radial thrust force on an end suction centrifugal pump shaft. It sometimes becomes confusing when you read other publications and find alternative formulas. Which ones are the best, and are they all correct? The fact is they;re all close enough for the work… Continue reading Pump shaft radial thrust alternative calculations (in Imperial dimensions) 13-2.

The non seal pump 3-11

Non-leak pumps have been the dream of pump designers ever since the first pump was invented back in the dark ages. We all want a non leaking pump for the obvious reasons: Pollution problems. Cost of the product. Housekeeping problems. The product is a potential danger to personnel. Leaking seals are the major cause of… Continue reading The non seal pump 3-11

All about specific speed 7-3

Specific speed is a term used to describe the geometry (shape) of a pump impeller. People responsible for the selection of the proper pump can use this Specific Speed information to : Select the shape of the pump curve. Determine the efficiency of the pump. Anticipate motor overloading problems. Predict N.P.S.H. requirements. Select the lowest… Continue reading All about specific speed 7-3

Selecting the correct elastomer (O- ring) for your mechanical seal application 4-9

This paper is to be used with the O-ring selection guide you’ll find in the chart and data section of this web site. The guide is an attempt to select the fewest number of elastomers that will give you satisfactory sealing of most of the chemicals we find in the process industry. As you can see from… Continue reading Selecting the correct elastomer (O- ring) for your mechanical seal application 4-9

Rules of thumb for pumps 2-7

If you want to know a pumps capabilities, the rules are simple. Look at the manufacturer’s published pump curve. The problem is that you do not always have the curve available. Pump companies test their pump to determine its performance, they have no need for general guide lines or “rules of thumb.” Over the years… Continue reading Rules of thumb for pumps 2-7

The difference between specific speed and suction specific speed 9-12

The best way to describe the shape of an impeller is to use its specific speed number. This is a dimensionless number that was generated by the formula : In the metric system we calculate the capacity in liters/sec and the NPSH in meters. You should try to keep the final SSS number below 5200.… Continue reading The difference between specific speed and suction specific speed 9-12

Troubleshooting mechanical seals at equipment disassembly 3-9

All seals fail for the same reasons: The faces open up and allow dirt or solids to penetrate. One of the seal components has been damaged by either the fluid you are sealing, heat, or a cleaner used to flush the system. After the failure has occurred you’ll frequently get a chance to analyze the… Continue reading Troubleshooting mechanical seals at equipment disassembly 3-9