The Safest Pumps for Chemicals
When handling dangerous or hazardous liquids, you must choose between the safest pumps for chemicals to ensure the safety of your staff and the environment. Hazardous chemicals are toxic, corrosive, or volatile chemicals that can affect your health and/or pollute the environment.
Hazardous chemicals are often found in the manufacturing and pharmaceutical industry, as well as wastewater treatment and chemical processing. Hazardous chemicals are also used for sanitation, metal finishing or food processing. Before deciding what pump can safely transfer hazardous liquids or chemicals, it’s important to understand the pumping principle and application.
The sealing system is crucial for the leak-free operation of a pump. Most shaft-sealed pumps need a sealing mechanism, which lies between the rotating shaft and the pumped fluid. These include:
- Lobe pumps
- Conventional Centrifugal pumps
- Conventional gear and vane pumps
- Progressive cavity pumps
A mechanical seal is a reliable way to prevent leaks. With spring-loaded tension, the mechanical seal creates a continuous sealing face with the pumped liquid – acting as both lubricant and coolant.
Magnetic drive pumps
The parts of a magnetic drive pump that come into contact with the pumped liquid are constructed from stainless steel or a plastic or metal lined with a polymer like ETFE. An effective lining such as ETFE provides resistance from corrosive chemicals and increases the durability of a metal casing. Because mag-drive pumps use two sets of magnets separated by a solid barrier, there is no physical connection or possibility of leakage or emissions. The seal-free design improves overall productivity, safety, and compliance.
Avoid magnetic-drive pumps when pumping viscous fluids (more than 200-250 cPs), or solids. Viscous fluids don’t enter the flow path easily, which places unnecessary loads on the bearings and assemblies of the mag-drive pump. Hard solids can also contribute to wear of the pump – and can even cause failure.
Positive displacement pumps
The peristaltic pump can be effective when used to pump chemicals. A peristaltic pump (hose pump) is useful for pumping abrasives, because it traps slurry or off-gassing fluids in the hose. The hose can be comprised of rubber compounds, which allows them to operate when the pumped fluid is a solvent or chemical not suited to rubber.
The hose affects the peristaltic pump’s lifespan. With normal wear, it loses elasticity, causing reduced suction capability and flow rate. To avoid hose rupture, it’s important to have a regular maintenance schedule and always check the hose for damage. One way to simplify this is to fit the hose with burst hose protection which can detect any build up in pressure.
If the pump’s hose ruptures, the pump’s casing, bearings, drive assembly and gear box can be damaged, often catastrophically.
Air Operated Diaphragm Pumps (AOD)
Air operated diaphragm pumps are made from metal or injection moulded plastics (like polypropylene or PVDF). These materials can handle most chemicals and solvents. If you’re facility pumps at high temperatures, moulded plastic pumps are limited to 90 degrees centigrade.
Diaphragms can be made from various materials, however for chemicals and solvents, PTFE is required. These diaphragms are crucial for separating the pumping liquid from the air chamber.
If ruptured, the liquid will enter the air suction. If a diaphragm pump is not made from a chemically-resistant material, the air chamber will be damaged by the hazardous chemical.
What to look for when choosing the most efficient pump for chemicals
Before selecting a chemical pump, consider the following:
- Correct pumping principal for the fluid’s characteristics, system, and frequency of operation
- Leak-free operation
- Chemical compatibility for all wetted parts
Always choose a chemical pump that you and your team can easily and safely operate without the risk of spillage, leakage, or off-gassing.
Can’t decide which pumping principle is right for you when trying to find the safest pump for chemicals? Give us a call on 1-800-367-4180 (toll-free). As your metering pumps supplier, we’re here to help you choose, install, maintain, and monitor a variety of equipment. And to answer questions about things you’ve previously tried gone wrong.