Pumps are critical to a range of industries, from chemical production and food processing, to wastewater treatment and biogas production. There are a number of different pump types on the market and choosing the right one for your process can seem like a daunting task. However, in today’s squeezed economy, maximising productivity is essential if companies are to remain competitive – and correct pump selection is key to this.
Productivity is measured by the ratio of output per unit of input. Many companies see it as a balancing act – how can they increase their output without increasing their costs? It is closely linked to efficiency, ensuring that every piece of equipment and every part of the process is optimised, delivering greater value for money to the operator.
Knowledge is power
The most important criteria when specifying a pump is to ensure that it will be fit for purpose. To do this, it is important to understand the product to be pumped, and the process involved. Is the product liquid or semi-solid? Is it viscous? Will it need to be transferred over a long distance, or pumped to height, for example to storage vessels and silos?
Other information must be provided, too. For example, does the product contain solid particles? Consider also whether it is shear sensitive, if the process needs a self-priming pump, or whether a suction lift is needed. Also bear in mind the length of the discharge pipework and the configuration regarding bends and lifts. The more information an operator can provide, the more likely it is that they will get the right pump for the job.
After thoroughly researching the options available, it may transpire that more than one pump design is fit for purpose. In order to ensure optimum productivity, operators must then consider the total cost of ownership (TCO). The lifecycle cost of a progressive cavity (PC) pump, for example, is typically ten per cent capital purchase cost, ten per cent maintenance/spare parts, and eighty per cent energy costs (based on £0.10p per kW/hr over a 20-year period, using WIMES calculations).
With such a high percentage of a pump’s TCO coming from its running costs, selecting a pump which is energy efficient is key to enhancing productivity. Unlike piston, diaphragm and peristaltic pumps, PC pumps produce low pulsation flow and require smaller drives and motors for the same duty. And unlike air-operated pumps, they run on a direct energy source, without the conversion of electricity to compressed air. This all helps to reduce the energy required to run the pump. Some of the more intelligent pumping solutions on the market, such as SEEPEX’s Smart Conveying Technology (SCT), deliver even greater energy savings. By optimising the clamp between the rotor and stator, and using a variable speed drive, the SCT pump can be up to 20 per cent more energy efficient than traditional PC pump designs.
As maintenance and spare parts are responsible for 10 per cent of the TCO of a pump, finding a solution that is easy to monitor and maintain is also important. SEEPEX’s SCT range of progressive cavity pumps significantly improves whole life costs due to the ease of replacing parts and clearing blockages. The fact that these pumps can be remotely monitored also makes it easier to anticipate problems, enabling predictive maintenance. In addition, the use of variable frequency drives (VFD) means that speed can also be controlled. As pump performance drops over time, its speed will increase to maintain flow; the SCT pump can be quickly adjusted to regain its original capacity, keeping efficiency high and providing more time to plan for maintenance, resulting in less downtime. The use of level controls with VFD to speed and slow pumps, and the regular, laminar flow created, also helps to deliver a higher quality, more uniform pumped product and reduces the wear rate of the pump.
Beware hidden costs
Another cost consideration is whether a pump will require ancillary equipment. Many traditional pump designs require pulsation dampeners and check valves, all of which come at a cost to the operator, as well as being liable to blockages. In contrast, due to their constant, virtually pulse-free action PC pumps do not require dampeners, and the interference fit between rotor and stator negates the need for check valves, saving operators money and reducing downtime.
As well as keeping down the running, maintenance and system costs of a pump, operators can also reduce their initial purchase price by talking to their supplier about the different options available. For example, could a smaller, smarter pump do the same job as a larger, more expensive solution? Is it worth integrating a boundary layer injection system to reduce pipework friction losses further downstream? Could labour costs be cut by specifying a pump with excellent suction lift capabilities? A responsible pump supplier will work with an operator to specify the most cost effective solution for their needs.
A balancing act
While a low pump purchase price may appear attractive, with 80 per cent of the TCO coming from its running costs, keeping these lower over the lifetime of the pump will provide a greater return on investment. Whatever solution you choose, take into account its energy efficiency, maintenance requirements and the costs of any ancillary equipment before signing on the dotted line. Put simply, specifying the wrong pump could decrease your productivity – choosing the right pump will almost certainly increase it.