PUMP STANDARDS P048
A Quick check of existing pump standards will reveal that there are a number of them. The list includes:
- ANSI (American National Standards Institute) Standards for Chemical Pumps
- B73.1 for Horizontal type.
- B73.2 for Vertical Inline
- P3-A 003 End suction centrifugal pumps and mechanical seals for Active Pharmaceutical Ingredients
- Hydraulic Institute Standards
- API (American Petroleum Institute) 682 for centrifugal Pumps
- API 674 for Reciprocating Pumps
- API 675 for Controlled Volume Pumps
- API 676 for Rotary Positive Displacement Pumps
- API 682
- ISO (International Standards Organization) aimed at the medium duty single stage pumps ( Metric)
- ISO 21049
- DIN. West German industrial norm standard
- VDMA West German standard for pump seals.
The fact is that nationalism has caused many countries to adopt a standard for their own domestic pumps that is sometimes in conflict with the ISO (International Standards Organization) standard. There are two problems with almost all of these standards:
- Many of them were written for pumps equipped with jam-packing. Most of the standards were first written in the nineteen fifties at a time mechanical seals were not popular. In those days we had a lack of the modern materials that make mechanical seals practical. As an example Viton® was not invented until 1958 and did not come into general use until the sixties. Kalrez® did not come out until 1975 and in the eighties the duplex metals came into their own.
- The customer believes that by purchasing a standard design he is getting a high quality pump. Customers have the same problem with pump efficiency. They believe there is a correlation between efficiency and the quality of the pump. Needless to say there is none! Problems caused by these standards are reflected in continual poor seal performance. The fact of the matter is that these standards reflect only an attempt to standardize envelope (outside) dimensions, nothing more!
Unfortunately standardizing the envelope of pumps prevented manufacturers from designing shorter impeller shafts that were not prone to the bending problems associated with low cost ANSI and ISO (International Standards Organization) design pumps when they are operating off of their best efficiency point (BEP).