Shallow well jet pumps work in a simple principle. An electric motor drives an impeller which draws air from just above the water in the intake pipe. This creates a vacuum. Atmospheric pressure then pushes the water upward and into the pump. The jet pump needs water to pull new water up from the well so it must be primed. Priming simply involves pouring water down inside the pump body which is used to create a vacuum, a 1-way check valve is installed in the intake pipe leading to the jet. This keeps the water from running back down the well and helps to keep the jet pump primed. If the system is turned off for a long while this may cause the water in the pump body to evaporate in which case the pump will need to be re-primed. This type of set pumps can be used on walls where the static level is 26 feet or less.
2. Deep well jet pumps are for wells where the static level is 27′ or more. This system needs two pipes, a jet body and a foot valve.
These pumps are by far the most commonly used. The entire pump assemble including electric motor, which is water tight, is lowered into the well. Special waterproof cable is connecting to the electric motor providing power to the pump. The submersible works on an entirely different principle than the jet pump. This type of pump sucks the water from the well and pushes it up into the plumbing using a series of impellers. The impellers ride on top of each other separated by discs called diffusers and are connected to a central shaft which is driven by the electric motor. As water flows through each impeller its speed is increased and so is the pressure. Submersible pumps tend to be more efficient, producing more water with a smaller size motor.
Cold Storage Tank:
In older type pressure tanks the air and water are combined in the same chamber. Since air is lighter than water, it occupies empty space in the tank above the water. As more water is pumped into the tank the air becomes more and more compressed and pushes back against the water, creating a backpressure. This backpressure is used to push the water out of the tank and into the plumbing. There is one flaw in this design;however, air dissolves in water so over time the volume of air inside the pressure tank decreases and the backpressure created by it decreases. Therefore the tank must be recharged with air frequently. If the tank is not recharged, then pump continually will recycle.
The Bladder tank has a rubber bladder which keeps the water separated from the air. This keeps the air from being dissolved in the water and greatly reducing the frequency at which the tank needs to be recharged. The only downside to this type of tank is that the bladder flexes and contracts each time water is used and over time the bladder can develop holes. This is what’s known as water logging. In this case, the air volume inside the tank will gradually decrease just like with a captive air tank and if not properly charged, pump cycling will occur.