On a conventional pump, the spinning shaft has to pass through the casing to reach the impeller, and wherever it does there is a mechanical seal. Seals wear, and when they fail the liquid leaks out. For water that is a nuisance; for acid, solvent or anything toxic it is a serious problem. The magnetic drive pump does away with the shaft penetration altogether, and with it the leak.
We supply magnetic drive pumps from Gemmecotti and Flojet, and can source other makes for a specific duty. The ranges are below, or call +44 1332 913500 for help choosing.
A magnetic drive pump, also called a mag drive pump or magnetic coupling pump, connects motor to impeller through magnets rather than a physical shaft. The motor turns an outer ring of magnets, which spins around a sealed containment shell forming part of the pump casing. Inside that shell, a matching set of magnets on the impeller follows the outer ring through the magnetic field, so the impeller turns without anything crossing the casing wall.
Because the pumped liquid is sealed inside the shell and never touches a dynamic seal, the pump cannot leak through a failed gland. That single design choice is what makes a magnetic driven pump the natural answer for liquids you cannot afford to let escape.
The reason almost always comes down to containment. If the liquid is hazardous, corrosive, toxic, flammable, expensive or environmentally sensitive, a leak is a safety, compliance or cost problem, and a magnet drive pump removes that risk by design. The other benefits follow from the same seal-less layout:
The containment shell sets the pump’s chemical compatibility, so material choice is central:
Gemmecotti, one of the brands we supply, specialise in non-metallic mag drive pumps in PP and PVDF built for the chemical industry, covering flows from a few litres a minute up to large industrial duties. We also stock the Flojet magnetic drive range (AD, DC, GP, HPR, NDP and NEMP series), which covers lighter-duty and OEM applications.
Mag drive pumps are not right for everything. They want clean liquid, since solids and abrasive particles damage the shell, internal bearings and magnets. They must not run dry, because the liquid lubricates and cools the internal bearings and shell, and dry running overheats them fast. And they can decouple if the system resistance exceeds the magnetic coupling’s torque, which is why correct sizing genuinely matters here.
Selection runs on the usual centrifugal inputs, flow rate, total head, liquid properties (composition, viscosity, temperature, specific gravity) and material compatibility, with the added step of confirming the magnetic coupling has enough torque for the duty, particularly on high-viscosity or high-head jobs. Give us the duty and the chemical on +44 1332 913500 and we will recommend the right model and material.
If your questions have not been answered here, get in touch with our team for more information.
A magnetic drive pump is a seal-less centrifugal pump that uses a magnetic coupling to transfer torque from the motor to the impeller. Because no shaft penetrates the pump casing, there is no mechanical seal to fail and no possibility of leakage. Magnetic drive pumps are also known as mag drive pumps, magnet drive pumps or magnetic coupling pumps.
The motor drives an outer set of magnets mounted on the motor shaft. These magnets spin around a sealed containment shell that is part of the pump casing. Inside the shell, an inner set of magnets attached to the impeller rotates in sync with the outer magnets through magnetic force. The liquid is completely contained within the sealed casing at all times.
A mechanically sealed pump uses a rotating shaft seal to prevent leakage where the shaft passes through the casing. That seal wears over time and eventually leaks. A magnetic driven pump eliminates the shaft seal entirely by using a magnetic coupling to transmit torque through a sealed containment shell. The result is zero leakage and no seal maintenance.
No. The pumped liquid lubricates and cools the internal bearings and containment shell. Running a mag drive pump dry causes rapid overheating and can damage the bearings, magnets and containment shell. Every installation should include dry-run protection, typically a level switch or flow switch that shuts the pump down if liquid is lost.
Mag drive pumps handle virtually any clean liquid, including aggressive acids, alkalis, solvents, plating solutions, flammable hydrocarbons, pharmaceutical intermediates and ultra-pure water. The key requirement is that the liquid must be free of solids and abrasive particles. Material selection (PP, PVDF, ETFE, stainless steel, Hastelloy) is matched to the specific chemical being pumped.
The initial purchase price is typically higher than an equivalent mechanically sealed pump. However, the total cost of ownership is often lower because there is no seal to replace, less unplanned downtime, no fluid loss from leakage, and no environmental clean-up costs. For hazardous or expensive liquids, the payback on the higher upfront cost is usually rapid.
