Feb 282011

At Jim Murray, Inc. we specialize in sump, sewage and wastewater pump and pumping related products for residential and commercial applications. In this blog article we will try to break down the most common categories and offer a description to help you identify your product and how it works.

4 Pump Calcifications We Deal With

Dewatering Pump:

Generally referred to as a drainage or clearwater sump pumps. Dewatering pumps have screens which prevent the solids from entering the pump. These pumps are used to pump ground water out to grade or to a storm sewer. These pumps usually have a 1-1/4″ or 1-1/2″ discharge.

Effluent Pump:

Effluent pumps are rated for the use in sanitary sump drainage applications. These pumps are designed to pump grey water and capable of passing limited amounts of ½” or 3/4″ solids. The sump basin used must be gas tight and vented according to code. Most often these pumps are 1-1/2″ discharge, and sometimes they are 2″ discharge. Effluent type pumps are often used in septic and or mound systems.

Sewage Pump:

Sewage pumps are used in sanitary pumping applications where toilets are being used. These pumps are capable of passing 2″ solids. As with effluent pumps, sewage pump basins must be gas tight and vented according to code. 2″ discharge is very common, but 3″ discharge may also be found on older residential or commercial applications.

Sewage Grinder Pump:

Grinder pumps are very powerful sewage handling pumps that actually chop, grind, and shred the sewage and reduce it to a slurry. Sewage grinder pumps are capable of pumping this slurry through smaller diameter pipe and for much higher and longer distances than a sewage handling pump. 1-1/4″ discharge is common, however the discharge pipe may be increased to a larger pipe size.

How your pump works:

All of the above pumps have impellers that are attached to the shaft of the pumps motor and turn inside of the pump volute to eject the liquid. Below is a list of common sump and wastewater impellers. Attached are cut away drawings that will give you a visual idea of the internal design of each impeller.

Vortex Impeller:

A vortex impeller is located at the top of the pump volute, as it spins it creates velocity that transfers the liquids and solids. By theory, this impeller is a better selection for handling solids than a deep vane impeller because the solids are less likely to come in contact with the impeller. (Please see 18S cut away)

18S Cut Away

Deep Vane Impeller:

The deep vane impeller paddles the liquid and solids. Pumps with these type of impellers typically will produce a greater gpm outlet. (Please see 16S cut away)

16S Cut Away

Vortex Grinder Pumps:

A grinder pump uses a cutter and shredder to reduce the solids to a slurry. As the solids pass through the cutter they reach the volute where a vortex impeller passes the slurry along. (Please see Omni Grind+ cut away)

Omni Grind + Cut Away

Progressive Cavity Grinder Pumps:

This grinder too has a cutter and shredder to reduce the solids to a slurry. The slurry is then removed by the positive displacement of a rotor and a rubber stator. (Please see UltraCav cut away)

UltraCav Cut Away

So there you have it, hopefully you now have a better understanding of how your pump works.

Feb 092011

A lot of motor powered tools and appliances are rated by horsepower. The technical definition of horsepower is, horsepower is a unit for measuring the power of motors, one horsepower equals 33,000 foot pounds of work per minute. A foot pound is the amount of energy required to raise a one pound weight a distance of one foot.

What does all that mean? If you were an engineer you would be familiar with a formula that could chart the efficiency and recommend the best product for the job. For the average Joe or Jim, more horsepower means more power, which is not always the case….

In terms of sump pumps we look more at gallons per minute and hour more than at horsepower. Most sump pumps are rated by horsepower, but are also rated by gallons per minute and gallons per hour. Every pump has a performance curve that is based on the gallons per minute on the horizontal axis; and the vertical lift which is also called total dynamic head on the vertical axis. (Please see below for examples of various pump curves)

Pump Curve Example 1

Pump Curve Example 2

Most 1/3 horsepower sump and effluent pumps will deliver between 35 and 50 gallons per minute at 10 feet of vertical lift or total dynamic head. There are 1/3 horsepower effluent pumps that will pump 60 gallons per minute at a 10 foot total dynamic head. I can also site examples of pumps that are rated at ½ horsepower that will pump less than 70 gallons per minute. The actual performance has to do with the RPM of the motor, the amount of copper or metal in the motor, the size of the impeller and the design of the pump volute (the pump base or case).

What does this mean? Well, it means don’t purchase a sump or effluent pump based on horsepower, look at the gallons per minute or gallons per hour first. Then I suggest looking at how much electricity or the amp hour rating the pump has. The lower the amp rating the more efficient, or less energy will be consumed.

There are now sump pumps on the market that are equipped with a PSC motor, a “Permanent Split Capacitor” that are very efficient and can consume up to 40 or 50% less energy and deliver more gallons per minute or gallons per hour than ever before. (Please see our specifications for model # PZM-EP-33V-SJ http://www.jimmurrayinc.com/pumps_detail.asp?id=120)

How much can you save with an energy efficient sump pump? If the average cost per kilowatt hour is $0.12 and your pump runs for 5 minutes per hour year round you could save as much as $50.00 a year. (Please see The Definition of Green is Pro Series Pumps)