Pumps Industry
Pumps are everywhere. There are pumps in your car, pumping fuels, coolants, controlling battery temperatures; pumps in your house, pumping the central heating, pumping in the white goods; pumps in your factory doing all manner of jobs and pumps in your hospital, pumping blood and other fluids. Bigger pumps will deliver the water in the mains and pump sewage, and work hard in refineries. The list just goes on.
Driving pumps with electric motors uses a remarkable proportion of the world’s electricity. Some estimates suggest that 50% of all the electricity generated in the world is driving pumps.
Changes in the industry
The pump industry is well established, with original inventions going back many centuries, originally for irrigation. But it isn’t standing still. The new requirements are for control, efficiency and reliability. Look at it like this: Years ago, a cooling pump simply stopped a system from overheating. Now a temperature control pump will maintain a system at a tightly controlled temperature, and keep it operating within close limits. Sophisticated variable speed electric drives are replacing fixed speed drives. The need for improved efficiency cuts two ways; there’s the reduction in use of energy to drive pump, but also the improved efficiency of the system the pump is serving. Reliability is also a major focus, as an inexpensive pump that let’s down an expensive system isn’t an inexpensive pump at all.
Different Supplies
At Motion Control Products, we have supplied motors and drives for many different types of pump system. A clear division is between AC and DC supplies. DC is becoming more common, not just in vehicular transportation applications but also in machines where DC is used for all ancilliaries.
We supply a wide range of DC motors with a huge range of capabilities. Pump applications vary widely: at one extreme, we see applications with short duty cycles and a low cost requirement where a brushed DC motor will be satisfactory. We also see applications where duty is continuous, reliability is paramount and control is essential. For those, we will supply brushless dc motor systems and sophisticated control systems. For OEM applications, we can even design bespoke motor control systems and develop them for our customers.
We are seeing many applications for new technologies such as the maintenance of temperature in battery systems and fuel cells. These systems often require really consistent temperatures to be maintained and a variable speed pump will be needed to perform this type of duty.
In the world of AC motors, some of our customers use induction motors. Although unsophisticated, for an application with a reasonably consistent loading, the induction motor remains a reliable solution and can have reasonable efficiency. Induction motors are made in colossal volumes and benefit from well established technology and economies of scale. AC motors can be controlled with inverters which vary the frequency of the electrical supply to control the speed of the motor. This again is well established technology and inverters are both robust and competitive.
Getting the Size and Performance Right
Sizing of electric motors for pump applications is all about performance and temperature. In the most adverse conditions, we need to be confident that the motor temperature will stay within acceptable limits. We work with our customers to define what the most difficult conditions are, which might be the highest ambient temperature and highest loading, and then help to carry out tests to ensure that the motor is working effectively within limits.
Fundamental Pump Types
There are two fundamentally different types of pump. Positive displacement pumps deliver approximately the same amount of fluid for each rotation of the pump. For these pumps, the traditional method of flow control was to use a relief valve, so that when a certain pressure is achieved, the relief valve opens and surplus flow is re-circulated. This is intrinsically inefficient, and a speed control system is a far better option. More precisely manufactured positive displacement pumps can use rotational speed as a measure of flow rate, though less precise pumps will rely on a flow meter which will have some sort of feedback to the motor speed control. Positive displacement pumps generally rely on contact between pumps parts and are typically used for more lubricating and viscous fluids.
Centrifugal pumps are different. These pumps are more frequently used for water and lower viscosity fluids. Although there isn’t the same relationship between speed and flow rate, the energy used by these pumps increases dramatically with speed and there is every incentive to control their speed. Centrifugal pumps are common in cooling and heating systems, whether this is a system for heating a house by a heat pump or a traditional boiler, or a pump for maintaining battery temperature in an electric vehicle.
The diaphragm pump is a popular type of pump. Very rugged and durable, they put up with a lot of abuse and work effectively with difficult and contaminated fluids. Smaller diaphragm pumps are used in recreational vehicles and boats and bigger ones in various industrial applications. The larger ones tended to be driven by air but electric drives are becoming more popular due to their efficiency and ability to be controlled. We're familiar with the application of diaphragm pumps and their special characteristics, notably the need to have larger bearings on the pump side of a motor.
Enclosures
The enclosure for a motor driving a pump is rated according to IP ratings. Some of our customers require very high IP ratings, such as IP69K which allows for pressurised washing. At the other extreme, some customers build machines where the machine itself acts as the enclosure and motors are open frame offering in themselves no protection at all to keep costs down.
Customisation
We find that many of our OEM customers want to build the pump directly onto the motors they buy from us. We sometimes make special shafts, special terminal boxes, special end castings and other changes that are required to make fitment of pumps easy and to minimise cost and dimensions. We can also help with the design of the special parts, with their prototyping and the tooling for the parts and help control the supply chain from our factories.
In Summary....
We have the experience to help develop the specification for motor and drive systems for pumps and the capability of sourcing solutions and supporting development programmes. Let us know if we can help you with your development programme.
MCP can supply the following for your project:
Induction Motors
We supply a range of induction motors. These are an economical purchase and are sturdy and reliable. They are ideally suited to OEM applications, for which we can make custom designs to suit your pumps.
Servo Motors
With ever increasing requirements for control over systems, our ranges of servo motors will offer feedback on speed and where required position. Feedback on speed is ideal for control of such as cooling systems.
Gearboxes
Although many pumps run at synchronous motor speeds, some applications will run relatively slowly and benefit from a gearbox. Examples of these are positive displacement pumps such as lobe and gear pumps, or specialised pumps such as peristalitic pumps.
AC Inverters
An AC Inverter is a form of Variable Frequency Drive, taking in mains power and supplying variable frequency output. This can be used to operate pumps at a higher rotational speed than normal to increase output, or at a slower speed to save energy.
Servo Drives
Where precise control is required, our ranges of servo drives will give the ultimate in control.
The Full Solution
We always integrate our different offerings to create a coherent overall solution for our customers' applications. Do speak to us about your needs, and we will always work with you.