SELF-PRIMING TANK

Installing a self-priming tank, if your SAL pump is used for vertical, upward suction, it will be possible for you to use the pump for the following applications:

1. Install where a general-purpose pump with foot valve is being used. There are many cases of problems arising with a foot valve pump because the valve does not operate correctly, breaks down or causes wear of the pump body.
2. Install where a self-priming pump is being used. There are many
cases of problems arising due to inefficiency caused by the length of time it takes for priming, malfunction of the check valve on the suction side and wear of the pump body.

3. Install where a submersible pump is being used. There are many
cases of problems arising from frequent breakdown of the mechanical seal due to dirt and sand, and extreme wear of the pump body.
4. Install where a vertical shaft pump is being used. There are many
cases of problems arising from wear of the submersible vertical shaft bearing, and the frequent necessity of inspection for repair.

Principles of Self-Priming:

Pumping by means of siphon action

Once the pipes are filled with water (a variety of methods can be used to do this) pumping will be sustained naturally. When the water in a section of piping beings drop, a vacuum is created at the upper end of the pipe.

The atmospheric pressure on the surface of the water in the water tank forces water in the tank up into the pipe so that it is once again full of water. (In a vacuum, atmospheric pressure has enough power to push water up 10 meters.) This is why pumping is sustained when the pipe are full. If the pipe
that is in the water tank is punctured, air will enter through the hole making siphoning impossible and forcing pumping to stop.

How to Use the Self-Priming Tank

1-Open the air release valve (a) and the feed water valve (b) and fill the tank with water.
2- After the tank has been filled to the point where water overflows from the top of the suction pipe, close valve (a) and (b) and start the pump.
3-As the water in the tank is sucked up by the pump, its level will gradually drop and the pressure level in the tank will also drop. However, once pressure has dropped to a certain point, the same siphon principle operates. The water in the water tank on the suction side is pushed by a atmospheric pressure into the tank.
4-Therefore, when a pump is operated with a self-priming tank there is no need for a foot valve. When the liquid pump contains slurry, the foot valve seat is often worn to the point where it no longer function and it becomes impossible to operate the pump. With an EBARA Self Priming Tank, however, this sort of trouble will never arise.

5- Even when the pump is stopped, all water in the tank will not drain which means it is possible to start the next pump operation without any preparation. Note, however, that if the tank is punctured or suction
piping is damaged, self-priming will no longer be possible and the pump will not be able to function.

Model and Specifications

DIMENSION – SAL QT SELF-PRIMING TANK

Notes on Installation

• One self-priming tank should be installed for each pump.
1 – Pump suction piping:

a- Connect self-priming tank and pump with no more than two meters of straight piping.
Avoid to use elbow as much as possible.

b- Never allow air in the suction side since pressure will drop.
2- Pump discharge piping:

a- Discharge piping should be higher than top of tank.Total discharge piping length should be as shown in table below

b- The end of the discharge piping should be higher than suction water level

c- Do not use a check valve. Install so that there will not be a reverse flow at the end of the discharge piping.

d- Do not use a check valve. Install so that there will not be a reverse flow at the end of the discharge piping.

e- When a pump is not operating for extended periods, or when it is a type that does not use external feedwater, add water to the tank occasionally.