Many industrial chemical applications involve mixing to create a different product, keep chemicals in suspension, for wastewater treatment purposes, or to dilute the chemical. Polyethylene tanks are well-equipped to handle that type of process, as most chemicals being mixed can be safely combined. There are two basic types of mixing systems that our tanks use—mechanical mixers and pumps.
Properly designed mixer systems should be simple to own and operate. Let’s explore the components and considerations of a safe, cost-effective chemical mixing system for polyethylene tanks.
Mechanical Chemical Mixer Systems
Poly Processing offers several different styles of mixer mounts, depending on the mixer configuration:
Clamp-on mixer attachment—Used on small vertical tanks with very small and lightweight mixers
Small freestanding mixer support—Ideal for small open-top tanks with small and lightweight mixers
Vertical tank supported mixer bridge—For small to medium size vertical tanks.
Large vertical or open-top tank freestanding mixer bridge—Used on vertical tanks and open-top tanks with very large mixers.
Poly Processing Company can install baffles into the tank wall, if required.
Several loads and strains must be considered when identifying the best type of mechanical mixer for your poly tank. It’s critical to determine the downward load, bending load, weight of the mixer, torque load, horsepower, and correct angles to ensure the proper bracketing is designed into the tank mixing system.
If the mixer isn’t properly mounted and bracketed, improper mixing can result in additional costs of wasted materials, and potential damage to the mixer or even the tank. The mixer agitator must be supported by a bracketing system or attachment that is compatible with your particular storage tank.
The mechanical mixing system is efficient and reliable when installed properly, but there are some disadvantages to using it, including:
Space—often the mixing brackets are very large and take up a great deal of space
Chemical compatibility—the mixing arm is usually made of metal, which can be susceptible to oxidizing chemicals
Cost—the mixer and corresponding bracket or attachment can be expensive
Chemical Mixing with a Pump
Mixing chemicals without a mixer involves using one or more strategically placed pumps to mix the chemicals inside the tank. It can be a better solution than mechanical mixing, if you’re concerned about avoiding the disadvantages of an agitator.
Pump mixing is similar to a swimming pool, which drains water from the bottom of the pool and pumps it back in near the top of the pool, just under the water line. In a chemical tank, the liquid in the storage tank is mixed using a pump, which is plumbed to the tank to create a combination of vertical and lateral flows. In-tank mixing draws the fluid out of the tank, usually at the bottom, and returns it to the tank via a nozzle on the dome.
This nozzle, called an in-tank eductor, uses principles of fluid dynamics to pressurize the fluid. The combined stream produces a high-velocity flow that creates agitation, which mixes the chemicals in the tank. In some cases, mixing can occur with a pump discharge fitting only. Many pump experts, some of which even represent products called circulating tank eductors & tank liquid agitators, can assist you in proper sizing. This is often a great alternative to your tank having mixer equipment, but rather just fittings to accept the pump mixing system.
As in any chemical storage application, proper system setup comes down to the chemicals you’re using. The location and placement of the eductor and pump, their level, and their angles are all determined according to the particular chemical application. A chemical storage expert can help you choose the right locations and fittings for your mixing system.
Successful Tank Mixing Setup
We recommend contacting us before you begin designing the tank mixing system. We have engineers on staff that can help with selecting the proper mixer mount for your specific requirements.