This article discusses about jet pump use. In the name it suggests that jet pump is associated with a fast moving stream of fluid particles under high pressure.
A jet is nothing but a stream of fast moving particles due to high pressure. The high pressure pushes the fluid particles through a narrow opening due to which the velocity increases drastically increasing the force / impulse of the fluid stream. A pump as we all know is used to take fluid from lower potential to higher potential.
What is a pump?
A pump is a mechanical device that is used to transport water from a lower potential energy state to higher potential energy state. The potential energy value depends on the height of the fluid.
This means the water is pumped from a place which is at lower height to a place which is at higher altitude. Without any force, the water or any other fluid moves from higher potential to lower potential, it needs external force to take fluids from lower potential to higher potential. This external force is provided by a pump. We shall limit our discussion to jet pump in this article.
What is a jet pump?
A jet pump is basically an assembly of a centrifugal pump and a jet nozzle called as injector. The jet pump works on the principle of high pressure jet of fluid and the venturi effect.
The jet pump uses a jet of steam, air or water to displace the fluid from one place to another. The impulse produced by the jet of steam is used to displace the fluid particles. Jet pump is basically a centrifugal pump with a jet attached to it. In this article we shall study more about jet pump.
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How long should a jet pump run?
The pumos are not supposed to be operated for long hours. The pumps can although run on ON and OFF cycles. Simply put the jet pump should be run on an average ON OFF cycle of 2 minutes.
In a complete day, with repititive ON and OFF cycles, a jet pump can run for about two and a half hours. It should be given rest for some time and then again it should be turned ON. The closing time of the jet pump should also be equal to two minutes. This was the pump runs for two minutes and gets turned off for another two minutes.
How often should a jet pump run?
As discussed in the above section, a jet pump has a capacity to run for about two and a half hours in one day. To complete the task, we can run it intervals.
Intervals means that for some time the pump will turn ON and for some time it will turn OFF. The ON and OFF times of jet pump are same that is two minutes on average. So the jet pump will be turned ON for two minutes and will be turned OFF for another two minutes. This way the task can be completed in intervals.
How deep does a jet pump work?
The jet pump is of two types depending upon the depth of the water it has to work on. The two types will be discussed in detail in later sections of this article.
The shallow water jet pump can work upto depths of 25 feet. The water having a head of 25 feet can be drawn out by shallow water jet pump. Whereas to draw from deeper depths, deep water jet pump can be used. A typical deep water jet can draw water from the depths between 25 feet to 110 feet.
Types of jet pump
The classification of jet pumps are done on the basis of depth of water it has to draw from. According to this, the jet pumps can be classified into two main types. These types are given in the list below-
- Shallow water jet pump– As already discussed this type of jet pump is used to draw water of shallow depths. That is this jet pump can draw water out of a water column which is 25 feet deep.
- Deep water jet pump- As already discussed in the above section this type of jet pump is used to draw water out of deep water columns. The depth can vary from 25 feet to 110 feet deep.
Can you use a jet pump without using a pressure tank?
Jet pump uses high pressure jets to displace the water or any other fluid from one place to another. In most cases the jet pump uses a pressure tank which provides pressure to the stream.
This pressure makes the flow of stream faster and displaces the targeted fluid. Although, a jet pump can work without a pressure tank also. This can be done in expense to wearing of the pump. Hence it is desirable to have a pressure tank in a jet pump.
How far can a jet pump pull water?
The pump at ground level have a theoretical lifting capacity of water up to a height of 30 feet. If near vacuum conditions are made then the number may rise up to 35 feet!
The above cases were ideal and are correct in theory only. In practice we can have a design of centrifugal pump or jet pump with a lifting capacity of 25 feet only. This is because near vacuum conditions can not prevail and some mechanical losses are always present inside the pump.
Jet pump advantages and disadvantages
We have discussed about the concept of jet pump in this article. Now let us move forward to the most important part of this article that is advantages and disadvantages of a jet pump.
The advantages and disadvantages of jet pump are given in the section given below-
Advantages
- The jet pump does not have mechanical or moving parts in it. So the chances of wear and tear are less.
- It has a good capability to produce high productivity.
- It has a very long service life.
- The maintenance of this pump is very low and incurs less costs.
- To increase or decrease the productivity, a single injector displacement can adjust the magnitude of pressure.
- It can run for longer hours without any human intervention.
- It has a very high tolerance to abrasives present inside the liquid.
Disadvantages
- The efficiency of jet pumps are lower than other artificial lifts.
- Problem of space limitation arises.
- The jet pump has very high pressure surface lines.
- The jet pumps consume high power.
Can a jet pump overheat?
Any mechanical device gets heated after long hours of operation. Let us discuss when can a jet pump overheat while operation.
As the jet continuously works in the voltage range of 170 V to 240 V, the pump can get over heated. To prevent the over heat, a thermal sensor is attached to it which alerts the user before it touches excessive pressure.
What is a turbine pump?
A turbine pump is a centrifugal pump which is installed underwater connected to an electric motor via shaft. The basic function of the turbine pump is to pressurise the fluid and send it to the outlet.
The efficiency of these pumps are very high and they are mainly used for large pumping applications. The pump works with various stages, analogous to a train being pulled by multiple engines because the load of train is so much that a single engine cannot drive. Turbo pumps are usually used inside rockets to pressurize the rocket fuel and oxidizer.
Hi ….I am Abhishek Khambhata, have pursued B. Tech in Mechanical Engineering. Throughout four years of my engineering, I have designed and flown unmanned aerial vehicles. My forte is fluid mechanics and thermal engineering. My fourth-year project was based on the performance enhancement of unmanned aerial vehicles using solar technology. I would like to connect with like-minded people.