Benefits of Mag-Drive Pumps

A Closer Look at the Benefits and Operation of Mag-Drive Pumps

Ever since the days of the “shadoof”, a primitive lever-and-bucket device employed in Ancient Egypt to transfer water, and the more efficient “Archimedean screw” that followed, the use of pumps has grown steadily. Today, all manner of pumping devices, in all shapes and sizes, play a vital role not just within several industrial sectors but also in the day-to-day lives of most of the world’s citizens. Although not all of those in use will be of the type known as mag-drive pumps, each design is most suitable for its allocated task.

Everyday Uses for Pumps

The treatment of drinking water at municipal plants and its delivery to homes and business are only possible with some form of pump. If you happen to occupy a penthouse, several of these devices will probably be necessary to ensure that the water will reach your level. Similar, but more specialised, versions of these devices circulate the water needed to cool car, boat and aircraft engines, or to circulate the oil required to lubricate them. In certain circumstances, however, the only viable option will be to employ mag-drive pumps.

Potential Risks to Pumps

While capacity, delivery rate and pressure differential are all important properties of a pump, it must also be able to resist any potential damage that might arise from the fluids it is required to handle. The most common sources of damage it may have to face are the corrosive properties of certain chemical solutions and the abrasive effect of fluids that contain particulate matter. However, corrosion and abrasion are not the only potential threats to which a pump may be exposed. Transporting flammable liquids carries the risk of fire or explosion. In practice, handling such liquids is a task for which mag-drive pumps are well suited.

Pumps, Motors and Fires

It is the motor that poses a risk when pumping a flammable liquid such as kerosene, petroleum, or a volatile organic solvent such as benzene, alcohol or ether. Electric motors are prone to arc, and just a single spark can be enough to result in ignition – thereby increasing the chance of a fire or an explosion that could destroy costly plant equipment and threaten the lives of nearby factory workers. The innovative design of modern mag-drive pumps ensures that, at no stage, is it possible for a stray spark to make contact with any flammable liquid they may be transporting. So how does the design of these units achieve this?

Mag-Drive Pump Design

In most other types of unit, the motor is attached directly to the shaft that carries the impeller responsible for moving its contents. This direct connection requires seals that are subject to wear and tear, which might expose a flammable liquid to arcing by the motor. By contrast, in a mag-drive pump, the motor is not directly attached to the drive shaft but is located outside of hermetically sealed pump housing. By positioning it externally where there is no contact with the contents, this also removes the need to rely on the protection provided by vulnerable seals.

So, if the motor is not connected to the drive shaft, how can it be made to rotate? The answer lies in a physical phenomenon with which most people will have been familiar since childhood. Instead of turning the drive shaft, the motor drives an outer shell made up of magnets, each with the same pole facing the pump housing. Inside the housing of a mag-drive pump, and connected to the drive shaft, is a second shell of magnets. In this case, each of the magnets is arranged so that its outward-facing pole is opposite to those on the external shell but facing inwards. Because unlike poles attract, as the outer shell rotates it will pull the inner one in the same direction. In this manner, the motor’s kinetic energy can be transferred indirectly but safely to the impeller.

These units are not only useful for transferring flammables, however: the absence of seals with their tendency to become worn means that mag-drive pumps eliminate the possibility of leakage in any situation. Therefore, they are also the ideal choice for handling highly corrosive acidic or basic liquids and any that might be toxic or harmful in other ways. Also, when handling high-value exotic materials, a seal-less unit offers a means to prevent costly losses that might otherwise occur due to leakage.

Talk to Prochem

Prochem is a South African leader in pump technology and a supplier of a broad range of world-class products including mag-drive pumps, backed by expert service. Get in touch today and learn more about our products and services.

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