The recognition that sanitary collection and disposal of domestic waste must be considered a necessity, bringing with it, the need for systems which could adequately and proficiently carry waste for treatment. This resulted in an underground network of collection lines resembling a large stream fed by many tributaries. The same basic waste transporting system prevailed right up to the present.... it is in this manner that the underground arteries of each community feed the main influent line to the sewage treatment plant. As communities continue to grow, new develpoments and new industries are, in many cases, forced to utilize undeveloped areas in relativly low elevation regions. In order to maintain a workable network of underground collection lines, the system must be supplemented by so called sewage lift stations located a strategic points.

The true hurdles to be overcome with this problem have become clearly defined only in actual application. In the case of the sewage lift station, this hurdle can be summed up in one word - solids! There have been numerous approaches to a solution, but in practically every case either the installation or the pumping mechanism requires an undue amount of care and maintenance to prevent clogging or breakdowns. The first consideration must be the elimination of the bar screen, which has its proper place in the sewage treatment plant... thus eliminating the need for cleaning screens, and the disposing of such screenings. Secondly, with the bar screen eliminated, the pumping mechanism must accommodate the free passage of any solids that flow through the infulent pipeline, fittings and valves. The unit muprovide a positive, non-clogging discharge action that will efficiently move any solids entering the station. Fourth, the installation should provide clean and sanitary operation... eliminating undesirable wet well conditions, and permitting easy inspection or maintenance checks without exposure to sewage.

As a safety precaution and from an asthetic viewpoint, the fifth concideration must be a hermetically sealed design that prevents the escape of toxic or combustable gases, as well as nuisance odors.

Finally, the mechanism should possess a resonably flexible capacity to accommodate variations in flow... including the ability to deliver at somewhat higher than rated capacity during periods of unusual peak loads.

What is a Pneumatic Ejector?
The pnuematic ejector is a extremly simple yet reliable mechanism. Fundamentally, it consists of a receiver or "pot' that allows liquids and solids to enter without restriction. When the pot becomes filled, compressed air is introduced to displace the contents up to a higher discharge line. The Pneumatic Ejector is unique as a pumping mechanism because no mechanical parts are involved in the actual pumping of the material... and it has no practical limitations on head. Under normal flow conditions, the equipment is designed to operate with a one minute cycle. The cycle consists of two phases. Filling the pot, and then the discharging of its contents. Operation is fully automatic with a choice of electric or mechancial control systems.

You can now use the Carter Plunger Pump Selection System to assit you in your search for the pump which fits your specific needs.