Wells & Pumps
“From well to tap, the pumping system makes the difference”
Well pumps and pressure tanks are 2 very important components of your well system. We at Gallants have the knowledge and expertise to help you select the right water system for your needs and circumstances. We are a certified Sta-rite pump dealer. Sta-rite manufactures some of the best pumping systems in the industry. In addition to Sta-Rite, we also work with Gould systems and other major brands of pumps and water systems. Below you will find more detailed information. Don’t hesitate to contact us if you have any questions.
Shallow Well Pumps
Shallow well vacuum pumps are designed to extract water from cisterns and from wells no deeper than 25 feet. They can be either centrifugal pumps or jet pumps but jet pumps are more common.
Centrifugal pumps are designed for low suction heads (vertical lifts) and high capacities. As a rule they develop low pressures, usually 45 to 55 pounds per square inch maximum. They are most frequently used as water pumps when high volumes and low pressures are required.
A Jet pump is really a combination of two pumps: the injector jet and a centrifugal pump. If the jet is located in the pump itself, it is known as a shallow well pump and will lift water up to about 25 feet. If the jet is located down in the well below the water level then it is a deep well pump.
Jet pumps are self-priming, have no moving parts and do not require lubrication. Their efficiency is typically low (on average about 40%) and they provide low flows at high pressure. They also have a tendency to clog from scale and to collect mineral deposits in the pipes, which can break loose into the water supply. The use of copper tubing or plastic pipe in the well tends to reduce the clogging problem. Since the motors are above the water, they are easily accessible for service.
Deep Well Pumps
Deep well pumps are simple in operation. The foot valve below the jet holds water in the system. Above the surface is a standard impeller-diffuser type pump. The output of the pump is split, and half to three-fourths of the water is sent back down into the well through a pressure pipe.
The ideal working lift for a single stage deep well jet is 30 to 75 feet, although deeper levels are possible, while a shallow well jet is limited to about 25 feet
The Foot valve is mounted below the pump at the bottom of the well. It is the first mechanical component to contact the water in the well. It is a crucial element in the system and performs a number of key functions.
- It receives the water into the system and feeds the pump.
- It filters sediment and debris out of the well or cistern water and keeps it away from to the pump.
- It maintains the pump prime and prevents the pump from running dry by turning it off if there is no water in the valve.
- It prevents the backflow of water from the system back into the well.
The Foot Valve is designed with a slightly larger flow area than the pipe size to insure minimal head loss. They are designed to be self-cleaning. Fig. 3 illustrates a typical foot valve cross-section.
Submersible pumps are vertical turbine type pumps. They place all the major pump components at the bottom of the well. This allows much greater efficiency in the operation of the motor, reduces friction, allows the water to cool the motor, and enables pumping from much greater depths. They can be single-stage or multistage for higher-pressure applications.
Pump bowls, which contain impellers and diffusers, are located below the water surface, and they should be submerged under pumping conditions. Submersible pumps eliminate the drive shaft and bearing systems of centrifugal pumps, thus reducing the mechanical complexity and required maintenance. Submersibles in deep settings are much more cost effective than other pumping means. Submersibles also do not require structures to enclose them and do not produce surface noise. Standard submersible motors are water-filled and rely on water as the internal lubrication for the motor. These motors are extremely reliable when applied within their design limits of temperature, hydraulic loading, and power requirements
We offer Grundfos Constant Pressure System pumps - submersible pumps that use a variable-speed motor to provide extra pressure when you need it. Constant Pressure submersible pumps offer the benefits of a municipal water supply by providing quiet, consistent water flow using an electronic controller that adjusts the speed of the pump to maintain the water pressure as need changes. The variable-speed motor handles most of the work and permits a smaller pressure tank.
Once the well has been drilled, the water in the well is available for use, but it must be extracted from the well and delivered under pressure to the building. This is accomplished by means of a well pump and a pressurized tank. The pump pressurizes the system as it extracts the water from the well and conveys it to the tank. The tank acts as a pressure regulator to the system by maintaining a constant outlet pressure.
One type of pressurized tank is called a bladder tank; it houses an inflated pre-pressurized polybutyl diaphragm (bladder). The pump feeds the inlet and, as it pumps, water stretches the diaphragm and displaces the air space it contained. As the tank fills with water, air pressure behind the diaphragm then builds inside the tank. Air pressure controls the water pressure. When the air pressure in the tank reaches the upward limit, a governing cut out switch turns the pump off. The system is protected with a pressure relief valve should the cut out switch fail. As water is drawn off by a faucet or fixture, the bladder retracts and the air pressure begins to drop inside the tank. When it reaches the lower limit of the range, the cut in switch turns the pump on again to recharge the system.
A typical pressure range is 30 to 50 psi. The pump cut in switch should be set at 2 psi higher than the pre-set tank pressure. That establishes the minimum allowable pressure and ensures that the pump will be turned on before outlet pressure to the house drops below the desired level. A pressure regulator controls the outlet pressure to the house so that it remains constant even though the internal pressure of the tank varies. The tank serves as a storage device as well as a pressure regulator. By storing water under a range of pressures, it permits small drawdowns such as in the flushing of a toilet or the washing of hands without turning the pump on. This saves wear and tear on the pump, which is important because repeated on/off cycling puts unnecessary stress on the motor.
The volume of water in gallons that can be drawn from the system before pressure drops to the cut in level is called the draw down, and the percentage of maximum draw down is called the maximum acceptance factor. Tanks are available in a wide variety of sizes and configurations. Tanks are designed for the location in which they will be installed, and for the type of pump that will feed them. They are rated as to size and output. An important concern is the length of time the pump must run to re-pressurize the system; the shorter the time, the better. The object is to keep pump run time to a minimum.