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All About Explosion-Proof Pumps

Mike Jeffries | December 3, 2018

explosion-proof pumpIn certain pumping applications, there can be sensitive hazardous conditions. It could be that the environment around the material to be pumped is explosive for one of several reasons. Or the material to be pumped itself could be considered hazardous. In both cases, the situation may call for a particular type of pump, known as an explosion-proof pump. This type of pump is designed to protect both the environment and the material to be transferred from pump related conditions that could cause detonation.

What Are Explosion-Proof Pumps?

Explosion-proof pumps are pumps that have a particular design to prevent internal or external explosions. The pumps have a construction that encloses the parts that could ignite the material being transported or found in the surrounding area. They are also designed to operate at a lower temperature than comparable standard pumps.

This pump type has many applications in different industries where potentially hazardous situations can arise.

Explosion-Proof Pump Design

In many ways, the explosion-proof pump is built like a standard wastewater unit. However, their durable housings, typically cast iron, are hydrostatically tested to withstand the forces of an internal explosion. In this way, any internal combustion is safely contained.

Explosion-proof pumps feature a long exhaust path built into their construction. This forces any released gases to travel the extended distance, reducing their exhaust temperature to a value considered safe for the immediate area.

The pumps incorporate a pilot thermal sensor located in the stator windings to monitor operating temperature. Thanks to the sensor, the pump will not exceed a safe temperature threshold at its surface, avoiding potential detonation of environmental gases. The maximum temperature allowed for exposed surfaces of explosion-proof pumps is 115 degrees Fahrenheit.

Explosion-proof pumps operate on either a dynamic or positive displacement design. The dynamic pump type uses fluid momentum and velocity as a means of generating pumping pressure. This version works well with variable flow requirements and low viscosity material. Dynamic explosion-proof pumps can deliver a high flow rate in hazardous areas. Centrifugal pumps are a dynamic pump design.

Positive displacement explosion-proof pumps use changes in cavity volume to transfer material. The positive displacement type is well suited for applications requiring a constant flow at high pressure with relatively low flow rates. This type of explosion-proof pump is ideal for hazardous areas with high viscosity fluids.


The major factors for requiring an explosion-proof pump are the material to be transported and the classification of the area. In many wastewater applications, explosive gases are a byproduct of their handling. Explosion-proof pumps are preferred in these applications.

Industrial Water can contain explosive material, such as oil, chemicals, and cleaning products. For safe transport of this type of material, explosion-proof pumps are usually the preferred means of liquid transport.

The environment at the pumping location can also dictate the use of explosion-proof pumps. Class I, Division 1, Groups C and D designations will typically mandate their use, but special zone designations can also require them.

Certain other situations can also call for the use of explosion-proof pumps. Class II, Division 1, Groups E, F, and G hazardous locations, such as coal and grain storage, typically use this type of pump.  Class II, Division 1 environments will also incorporate explosion-proof pumps.

Industries that regularly use explosion-proof pumps include refineries, petrochemicals, and other such areas. It should be noted that this type of pump is not rated for use in handling deliberate high concentrations of explosive material, including petrol and gas products.

Explosion-proof pumps are a particular pump type designed for hazardous locations and material. Mader Electric, Inc. specializes in explosion-proof pump repair and installation, as well as pump training. Contact us to see how we can help with your pumping needs.

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Topics: prevent industrial pump from needing repair, pump repair, explosion-proof motors, pump motors, pump technologies

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