Glossary

The piston pump is a positive displacement type of pump and it’s pretty much just like it sounds. As the piston is pulled back it draws in the fluid, and then as it’s pushed forward it pushes the liquid out. A piston pump can have up to four pistons depending on the application. They should only be used for clear liquids as any solids and/or abrasives in the fluid can damage the pump. Piston pumps are for low flow, high head applications. (Back to Top)

Manufacturers – Myers and General Pump

A slurry is defined as a suspension of solids in a liquid. Typically the liquid is water and the solids can be anything from soft materials such as sewage and food processing waste (potato skins, fish parts) to abrasive solids like sand, fly ash and coal. Mitchell Lewis & Staver Co. offers pumps to handle either a “soft” or “hard” slurry. Keep in mind a typical centrifugal pump really can’t handle more than 3% solids by weight. Specialty pump manufacturers like Toyo, Yamada and Liberty Process can handle higher solids concentrations.

Manufacturers for Soft Slurries – Yamada, Toyo, Landis, Polaris, Grindex and Liberty Process

Manufacturers for Hard Slurries – Toyo, Townley, Polaris, Grindex, Liberty Process and Yamada

The split case is almost synonymous with multi-stage and can be either horizontal or vertical.  Used where high pressures are needed such as boiler feed.

Manufacturers – Goulds and Weinman

Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses ultraviolet (UV) light at sufficiently short wavelength to kill microorganisms. It is used in a variety of applications, such as food, air and water purification. UVGI utilizes short-wavelength ultraviolet radiation (UV-C) that is harmful to microorganisms. It is effective in destroying the nucleic acids in these organisms so that their DNA is disrupted by the UV radiation, leaving them unable to perform vital cellular functions.

The wavelength of UV that causes this effect is rare on Earth as the atmosphere blocks it. Using a UVGI device in certain environments like circulating air or water systems creates a deadly effect on micro-organisms such as pathogens, viruses and molds that are in these environments. Coupled with a filtration system, UVGI can remove harmful micro-organisms from these environments.

The application of UVGI to disinfection has been an accepted practice since the mid-20th century. It has been used primarily in medical sanitation and sterile work facilities. Increasingly it was employed to sterilize drinking and wastewater, as the holding facilities were enclosed and could be circulated to ensure a higher exposure to the UV. In recent years UVGI has found renewed application in air sanitization.

Manufacturers – UV Atlantic and UV Pure

A variable-frequency drive (VFD) is a system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. A variable frequency drive is a specific type of adjustable-speed drive. Variable-frequency drives are also known as adjustable-frequency drives (AFD), variable-speed drives (VSD), AC drives, microdrives or inverter drives. Since the voltage is varied along with frequency, these are sometimes also called VVVF (variable voltage variable frequency) drives.  Variable-frequency drives are widely used. For example, in water booster stations, pump speed is controlled by the VFD based on system demand.

Manufacturers – Danfoss

Aeration is a unit process where air and water are brought into close contact. The main purpose of aeration is to remove dissolved gases like carbon dioxide, and to oxidize dissolved metals, for instance iron. Aeration can also be used to get rid of volatile organic chemicals in the water. Mitchell Lewis & Staver offer two basic type of aeration via our Landia line.

The combined mixer/aerator is submerged in tanks or lagoons.
The combined mixer/aerator work this way: The fast-revolving propeller create a strong vacuum immediately behind itself, which leads to atmospheric air (or pure oxygen) being drawn down through a pipe.
The injected air is mixed with the liquid while the liquid in the tank/lagoon is being mixed.

The Venturi AirJet system consists of one or two venturi nozzles which are connected to the well known Landia chopper pump.
When the pump is running, the liquid is drawn into the pump’s knife system, where any lumps are chopped into pieces.
The liquid is then pressed out through the mixing nozzle under high pressure. This creates a strong vacuum inside the ejector which draws atmospheric air (or pure oxygen) down through a pipe.
The injected air is mixed with the liquid while the liquid in the tank/lagoon is macerated and mixed.

Manufacturers – Landia

Centrifugal pumps are the most common type of pump in use today. A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the velocity of a fluid. Centrifugal pumps are commonly used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber, from where it exits into the downstream piping system.  A centrifugal pump works by the conversion of the rotational kinetic energy, typically from an electric motor or turbine, to an increased static fluid pressure. This action is described by Bernoulli’s principle. The rotation of the pump impeller imparts kinetic energy to the fluid as it is drawn in from the impeller eye (centre) and is forced outward through the impeller vanes to the periphery. As the fluid exits the impeller, the fluid kinetic energy (velocity) is then converted to (static) pressure due to the change in area the fluid experiences in the volute section. Typically the volute shape of the pump casing (increasing in volume), or the diffuser vanes (which serve to slow the fluid, converting to kinetic energy in to flow work) are responsible for the energy conversion. The energy conversion results in an increased pressure on the downstream side of the pump, causing flow.

Manufacturers – Price Pump, Gorman Rupp, Myers, Toyo, Wastecorp, Berkeley, Goulds, Sta-Rite, Deming, Weinman and AMT

A chopper pump is a centrifugal pump, which is equipped with a cutting system to facilitate chopping/maceration of solids that are present in the pumped liquid. The main advantage of this type of pump is that it prevents clogging of the pump itself and of the adjacent piping, as all the solids and stringy materials are macerated by the chopping system. Chopper pumps exist in various configurations, including submersible and dry-installed design and they are typically equipped with an electric motor to run the impeller and to provide torque for the chopping system. Due to its high solids handling capabilities, the chopper pump is often used for pumping sewage, sludge, manure slurries, and other liquids that contain large or tough solids.

Manufacturers – Landia

Any pump capable of removing water from an unwanted area.  They are usually small portable pumps that run on single phase power, compressed air or a small engine, but can be large permanently installed units as well.

Manufacturers – Toyo, AMT, Gorman Rupp, Myers, Grindex, CET Pump and Prosser

A dredge pump is a submersible, centrifugal pump capable of handling high solids concentrations and is typically used for clearing out and/or deepening harbors and waterways.  The material being moved, sand, dirt, soil, etc is carried away along with the water it is suspended in.

Manufacturers – Toyo, Grindex and Polaris

A grinder pump is a waste management device. Waste from water-using household appliances (toilets, bathtubs, washing machines, etc.) flows through the home’s pipes into the grinder pump’s holding tank. Once the waste inside the tank reaches a certain level, the pump will turn on, grind the waste into a fine slurry, and pump it to the central sewer system.

Manufacturers – Myers and Barnes

Most metering pumps are either a piston or bellows type of pump. They are used for precise introductions of chemicals into a tank, existing fluid stream or some other liquid handling equipment.

Manufacturers – Stenner

The multi-stage pump is used for clean, clear liquids requiring significant discharge pressure.  A multi-stage pump is nothing more than a standard centrifugal pump with the discharge of the initial volute discharging directly into the suction of the next volute.  The numerous “volutes” are all internal to the pump and many times the individual volutes are hard to spot individually.  The number of stages is dependant on the desired Total Discharge Head required by the application.  These types of pump can be either horizontal or vertical configuration.  Commonly used for boiler feed.

Manufacturers – Goulds, Berkeley, WILO, Price Pump, Burkes and Weinman

Powder pumps are normally of the Air Operated Diaphragm type and really can pump just powder and powder like materials such as flour and other fine grained, low bulk, dry-density powders in a dust free operation.

Manufacturers – Yamada

The progressive cavity pump is really a different type of animal. The pumping mechanism consists of a rotor that looks like a corkscrew inside a stator with a corkscrew shape cut out of it, but they are purposely off center from each other. As the rotor turns cavities in the stator are created and eliminated by the rotor/stator off center relationship. These pumps are ideal for thick slurries such as food waste, sludge, or any thick fluids. PC pumps have been used to pump ice, fish waste and even cookie dough. PC pumps typically operate at lower speeds, usually below 1000 rpm, and consist of the pump end, motor and reducing gear box.

Manufacturers – Liberty Process

Propeller pumps are similar to other impeller pumps, but the fluid being pumped is not sent in a circular path. Rather, it proceeds more or less in a straight direction up to the discharge. Here, the motor sits above the discharge shaft. The distance to the propeller is usually well under 100 feet and often between 10 and 20 feet. The propeller can be placed below the surface of the liquid, where it will always be primed. Propeller pumps are generally low-speed but low heads. They can be quite large, measuring over a dozen feet in diameter and moving over 50,000 gallons per minute. Some have adjustable-pitch blades.

Manufacturers – Fairbanks Morse

A Gear pump uses the meshing of gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. Gear pumps are also widely used in chemical installations to pump fluid with a certain viscosity. There are two main variations; external gear pumps which use two external spur gears, and internal gear pumps which use an external and an internal spur gear. Gear pumps are fixed displacement, meaning they pump a constant amount of fluid for each revolution. Some gear pumps are designed to function as either a motor or pump.

Manufacturers – Gorman Rupp

Sanitary pumps describe the materials used for construction of how a pump is built.  Typical describing words are “FDA Compliant”, “Food Grade” and “CIP (Clean in Place)”.  Sanitary pump are normally built from stainless steel, PTFE, EPDM and other “clean” materials.  We carry progressive cavity, air operated diaphragm and centrifugal type sanitary pumps.

Manufacturers – Yamada, Liberty Process and Standard Pump

Self priming pumps are centrifugal pumps with an abnormally large and odd shaped volute.  The purpose of the large volute is to allow the pump to pull or “lift” liquid up to the impeller.  Initially the pump volute (casing), must be filled with liquid manually.  As the pump starts it pumps out the liquid that was manually put into it while also drawing up the air in the suction pipe along with pulling up the liquid to be pumped.  As the lifted liquid enters the volute the final volume of air is pumped out of the discharge and through an air release valve.  Once the liquid hits the air valve, it closes and the pump now operates as a standard centrifugal pump.

Manufacturers – Gorman Rupp, Myers, Price, Yamada (AODD) and Crown

Many types of pumps can be used for solids handling.  The size and concentration of solids in the fluid will determine the best type of pump for the application.  For sewage applications such as lift stations where the solids concentration does not exceed 3%, but the solids size can reach 3” or 4” a centrifugal pump is usually the best choice.  For solids concentration above 3%, Air Operated Diaphragm, Progressive Cavity or even specialty centrifugal pumps can be used.  We do offer the Toyo line of centrifugal pumps which can handle up to 70% solids concentration by weight.

Manufacturers – Myers, Gorman Rupp, Toyo, Liberty Process, Yamada, Polaris, Grindex, AMT, Deming, Wastecorp and Rampart Pumps

A submersible mixer is a mechanical device that is used to mix sludge tanks and other liquid volumes. Submersible mixers are often used in sewage treatment plants to keep solids in suspension in the various process tanks and/or sludge holding tanks. The submersible mixer is operated by an electric motor, which is coupled to the mixer’s propeller, either direct-coupled or via a planetary gear-reducer. The propeller rotates and creates liquid flow in the tank, which in turn keeps the solids in suspension. The submersible mixer is typically installed on a guide rail system, which enables the mixer to be retrieved for periodic inspection and preventive maintenance.

Examples of applications where submersible mixers are commonly applied:

• Anoxic/anaerobic tanks and oxidation basins (activated sludge) at sewage treatment plants
• IFAS, MBBR, and other fixed film biocarrier processes.
• Mixing of sewage wet wells
• Reception tanks and post-digestion tanks at biogas facilities
• Liquid Manure storage tanks at dairy, hog, and poultry farms
• Waste processing at slaughterhouses, poultry abattoirs, fish processing plants, etc.

Manufacturers – Landia

Just like it sounds, these guys operate within the fluid they are pumping.  Submersible pumps can be either centrifugal or AOD type pumps.  The centrifugal versions are common used in sewage lift stations, while the AODs are used in chemical transfers.

Manufacturers – Myers, Gorman Rupp, Toyo, Yamada, Polaris, Grindex, Barnes, WILO Hydromatic, Goulds and Burkes

This style of mixer uses an extended shaft between the motor and mixing blade such that the motor is above and out of the liquid. These also incorporate a gear reducer to slow the speed of the mixing blades to achieve the desired fixing/tank turnover rate.

Examples of applications where submersible mixers are commonly applied:

• 55 gal drums
• Plastic and stainless steel totes
• Water and effluent treatment
• Rapid/flash mixing
• Flocculation
• Activated carbon slurry mixing

Manufacturers – Dynamix

A vertical turbine pump is a centrifugal type pump, often with multiple stages, where the motor is set at ground level and connect via shaft to the pump below.  Used as well pumps for irrigation, they can also pump from rivers, lakes and other bodies of water.

Manufacturers – Fairbanks Morse and Goulds

Well pumps are a centrifugal, submersible type of pump used for bringing underground water up to the surface for domestic use.  They can consist of one or several “stages” depending on the well depth and desired discharge pressure.  Electrically powered the motor is typically on the bottom of the pump with the suction in the middle and the water is pumped upwards through the impeller(s) and upwards toward the surface.

Manufacturers – Berkeley, Sta-Rite, Goulds and Aeromotor