Designing a New Chemical Pump for the Global Market

Related Vendors

The approach has been to offer two possible BEPs for each of the most popular sizes. The first hydraulic design provides relatively high flows, which leads to a downsizing of the pump size, i.e. the Mega CPK, pump size selected for a specific duty point is generally smaller than that following the values given in the standard. The customers will benefit from a lower price.

The second hydraulic design for the same pump size — with the same outline dimensions — follows the duty points specified in ISO 2858. This is important for replacement business. For 98 per cent of pumps, replacement is possible without changing the pipework.

Possible Variants of Chemical Pumps

Compliance with dimensional requirements alone is not enough to meet the expectations of the chemical industry. Even the requirements stipulated by the prescriptive ISO 5199 standard (Technical specifications for centrifugal pumps — Class II), which has to be fulfilled, may not be sufficient for specific applications. The main options for chemical pumps are discussed below.

Bearing Bracket Design

The minimum bearing lifetime required by ISO 5199 is 17,500 hours. For many customers, this service life is not in line with their requirement for 24/7 operation, while for other customers the investment cost aspect may be the most dominant parameter. As a result, KSB decided to accommodate both philosophies by offering appropriate technical solutions for both: The ‘economy’ bearing bracket version achieves a minimum bearing life of 17,500 hours, as stipulated by the standard. It is costeffective in that it uses single-row bearings.

The ‘medium-duty’ bearing bracket version, by contrast, is equipped with a roller bearing and angular contact ball bearings, so that bearing lifetimes of 100,000 hours ormore can be achieved in many cases.

Wet Shaft vs. Dry Shaft

Here, again, opposing philosophies have led to the development of different design options. While the wet shaft design aims to increase shaft stiffness, the dry shaft design is primarily used where cost plays a major role in combination with corrosion resistance.

(ID:42863778)