Ejector for a pumping station: principle of operation, device, installation rules

A deep aquifer is a common problem that is well known to many land owners.Conventional surface pumping equipment either cannot provide the house with water at all, or supplies it to the system too slowly and with low pressure.

This problem needs to be resolved as soon as possible. Agree, buying a new pump is an expensive undertaking and not always financially justifiable. A solution to this situation can be an ejector for a water supply pumping station.

We will tell you how to choose a suitable unit and install it without the help of specialists. We will also provide step-by-step instructions on how to make and connect a homemade ejector. All stages of work are accompanied by visual photographs.

Operating principle of the ejector

The deeper the water is, the more difficult it is to bring it to the surface. In practice, if the well depth is more than seven meters, surface pump copes with his tasks with difficulty.

Of course, for very deep wells it is more appropriate to purchase a high-performance submersible pump. But with the help of an ejector, it is possible to improve the performance of a surface pump to an acceptable level and at significantly lower costs.

An ejector is a small but very effective device. This unit has a relatively simple design; you can even make it yourself from scrap materials. The operating principle is based on giving the water flow additional acceleration, which will increase the amount of water coming from the source per unit of time.

This solution is especially convenient for those who are about to install or have already installed pumping station with surface pump. The ejector will allow you to increase the depth of water intake to 20-40 meters.

It should also be noted that the purchase of more powerful pumping equipment will lead to a noticeable increase in energy consumption. In this sense, the ejector will bring noticeable benefits.

The ejector for a surface pump consists of the following elements:

• suction chamber;
• mixing unit;
• diffuser;
• narrowed nozzle.

The operation of the device is based on Bernoulli's principle. It states that if the speed of a flow increases, an area of ​​low pressure is created around it. In this way, a rarefaction effect is achieved. Water enters through a nozzle, the diameter of which is smaller than the size of the rest of the structure.

This diagram allows you to get an idea of ​​the design and operating principle of an ejector for a pumping station. The accelerated reverse flow creates an area of ​​low pressure and transfers kinetic energy to the main flow of water

A slight narrowing gives the water flow a noticeable acceleration. Water enters the mixer chamber, creating an area of ​​reduced pressure inside it. Under the influence of this process, a stream of water under higher pressure enters the mixer through the suction chamber.

Water does not enter the ejector from wells, but from the pump. Those. The ejector must be installed in such a way that part of the water raised by the pump returns to the ejector through the nozzle. The kinetic energy of this accelerated flow will be constantly transferred to the mass of water that is absorbed from the source.

To create an area of ​​rarefied pressure inside the ejector, use a special fitting, the diameter of which is smaller than the parameters of the suction pipe

This will ensure constant acceleration of the flow.Pumping equipment will require less energy to transport water to the surface. As a result, its efficiency will increase, as will the depth from which water can be drawn.

Part of the water extracted in this way is again sent through the recirculation pipe to the ejector, and the rest enters the water supply system of the house. The presence of an ejector has another “plus”. It sucks up water on its own, which additionally protects the pump from running idle, i.e. from the “dry running” situation, which is dangerous for all surface pumps.

The diagram shows the structure of the external ejector: 1- tee; 2 - fitting; 3 — adapter for water pipe; 4, 5, 6 - corners

To regulate the operation of the ejector, use a regular tap. It is installed on a recirculation pipe, through which water from the pump is directed to the ejector nozzle. Using a tap, the amount of water entering the ejector can be reduced or increased, thereby reducing or increasing the rate of return flow.

Choice: built-in or external?

Depending on the installation location, there are remote and built-in ejectors. There is no big difference in the design features of these devices, but the location of the ejector still affects in some way both the installation of the pumping station and its operation.

So, built-in ejectors are usually placed inside the pump housing or in close proximity to it. As a result, the ejector takes up minimal space and does not have to be installed separately; it is enough to carry out the usual installation of the pumping station or the pump itself.

In addition, the ejector located in the housing is reliably protected from contamination. Vacuum and reverse water intake are carried out directly in the pump housing.There is no need to install additional filters to protect the ejector from clogging with sludge particles or sand.

A remote ejector for a pumping station is more difficult to install than an internal model, but this option creates a much less noise effect

However, it should be remembered that this model demonstrates maximum efficiency at shallow depths, up to 10 meters. Pumps with a built-in ejector are designed for such relatively shallow sources; their advantage is that they provide excellent incoming water pressure.

As a result, these characteristics are sufficient to use water not only for domestic needs, but also for irrigation or other economic operations. Another problem is the increased noise level, since the vibration of the operating pump is added to the sound effect of water passing through the ejector.

If you decide to install a pump with a built-in ejector, you will have to take special care of sound insulation. It is recommended to install pumps or pumping stations with a built-in ejector outside the house, for example, in a separate building or in a well caisson.

The electric motor for a pump with an ejector must be more powerful than for a similar model without an ejector.

An external or external ejector is installed at a certain distance from the pump, and this distance can be quite significant: 20-40 meters, some experts even consider 50 meters acceptable. Thus, a remote ejector can be placed directly in a water source, for example, in a well.

The external ejector does not so much increase the pump’s performance as it is designed to increase the depth of water intake from the source, which can reach 20-45 m

Of course, the noise from the operation of an ejector installed deep underground will no longer disturb the residents of the house. However, this type of device must be connected to the system using a recirculation pipe through which the water will return to the ejector.

The greater the installation depth of the device, the longer the pipe will have to be lowered into the well or well.

It is better to provide for the presence of another pipe in the well at the design stage of the device. Connecting a remote ejector also involves installing a separate storage tank from which water will be drawn for recirculation.

Such a tank allows you to reduce the load on the surface pump, saving some energy. It is worth noting that the operating efficiency of the external ejector is somewhat lower than that of models built into the pump, however, the ability to significantly increase the intake depth makes one come to terms with this drawback.

When using an external ejector, there is no need to place pumping station directly next to the water source. It can be installed in the basement of a residential building. The distance to the source can vary within 20-40 meters; this will not affect the performance of the pumping equipment.

Device installation features

As already mentioned, installing an ejector built into the pump does not cause any particular problems, since the device is already located in the device body. The surface pump is simply connected to the water supply hose on one side, and also to the water supply system on the other side.

If it is used as part of a pumping station, then the pump is connected to hydraulic accumulator through a special fitting for five outputs.In addition, the pump will need to be connected to the contacts of the pressure switch to ensure that it turns on and off automatically.

This diagram clearly shows the procedure for connecting a remote ejector to a pumping station, indicating the installation locations of all necessary components.

Before turning on the surface pump, it must be filled with water through the filling hole provided for this purpose. You cannot turn on such equipment without water, it may burn. If the pump is installed correctly, the ejector will operate without interruption.

But the installation of a remote ejector is carried out according to a more complex scheme. First, you will need to install a pipe that will ensure the return flow of water from the storage tank to the ejector. Install on the suction section of the ejector check valve. A mesh filter should be placed behind it to protect the device from clogging.

An adjustment valve must be installed on top of the recirculation pipe to regulate the amount of water that is directed to the ejector. This unit is not mandatory, but can significantly improve the situation with water pressure in the house.

The less water is returned to the ejector, the more of it will be left for the home's plumbing system.

The ejector is assembled before operation according to the standard scheme. A mesh filter is connected to the ejector body from below, and a Venturi tube made in the form of a plastic socket (+) is connected to the top through the nozzle.

In this way you can influence water pressure in the water supply. If it is insufficient, you should slightly tighten the adjusting valve on the return line.

If the pressure is too high and creates unnecessary stress on the plumbing system, it makes sense to direct more water to the ejector in order to increase the efficiency of the pumping equipment.

Some industrial models of ejectors are already equipped with such an adjustment system. The instructions that come with the device usually describe in detail how to configure the ejector.

Using a homemade external option

A built-in ejector is usually purchased at the same time as a pump, but the external model is often made by hand.

It will be useful to consider the creation process and the procedure for connecting such a device. In order to make an ejector, you will need such parts as a tee with internal threaded connections, fittings, fittings, bends, couplings, etc.

Personal assembly of the ejector

Assemble the device as follows:

1. Connect the lower part of the tee to the fitting so that the outlet pipe is at the top, and the fitting with a smaller diameter is inside the ejector.
2. Then you need to modify the design by cutting off the narrow part of the fitting if it protrudes from the tee.
3. If the fitting is too short, it is extended using a polymer tube.
4. An adapter with an external thread is screwed onto the top side of the tee.
5. A PVC water pipe is connected to the other end of the adapter using a fitting.
6. Now, a bend in the form of an angle should be attached to the lower side of the tee, into which a narrow fitting is already inserted.
7. A pipe is connected to this outlet, through which the reverse flow of water will flow to the ejector.
8. Another corner is attached to the side pipe of the tee.
9. A pipe is attached to this corner using a collet clamp; water will be sucked through it from a well, well, etc.

The distance between the edge of the tee and the fitting should be approximately 2-3 mm. This will ensure the creation of a vacuum region with the necessary characteristics. To secure the recirculation pipe, use a crimp nut.

It turns out that two elements are simultaneously attached to the internal thread of the lower branch pipe of the tee. One of them (fitting) is located inside the tee, and the second (angle) is outside. In order for both of them to fit on one threaded connection, part of the thread of the fitting should be cut off.

Of course, all threaded connections must be sealed and sealed. Most often, FUM tape is used for this. Sometimes to connect the ejector to pumping station They do not use metal-plastic pipes, but polyethylene structures.

To install them, you should use special crimping elements, and collet clamps, which are good for metal-plastic, are not suitable in this situation.

All threaded connections of the ejector should be carefully sealed and sealed, for example, using FUM tape or other suitable material

Pipe connection procedure

You should think in advance about which pipes the remote ejector will be connected to. Polyethylene structures bend well when heated, which makes it possible to do without corners when connecting the ejector. The pipe is simply bent in a suitable place and at the desired angle, and then attached to the ejector.

To connect the ejector, you can use polyethylene pipes, which are easier to install than similar structures made of metal-plastic

So, the device has three outputs, to each of which a corresponding pipe should be connected. First, a pipe is usually installed through which water will be drawn from the source. It connects to the side outlet of the ejector.

A check valve must be installed at the end of this pipe, as well as a strainer. This pipe must be long enough to reach deep into the water. But you should not take water from the very bottom of the source, as this can lead to clogging of the ejector, even despite the presence of a filter.

You can then attach the pipe to the lower end of the ejector, which has a tapered fitting. This is the pipeline through which water is recycled. The second end of this pipe should be connected to a container from which water will be drawn to create a return flow.

The third pipe is a regular water main. One end of it is mounted on the upper pipe of the ejector, and the other is connected to the surface pump. It should be remembered that the diameter of the pipe through which water is drawn from the source must exceed the size of the pipe through which water is supplied to the ejector.

Three pipes are connected to the remote ejector: a pipe for sucking water from the source, a pipe connecting the device to the pump and a line for recirculating water

If an inch pipe is used for supply, then it is recommended to use a quarter-inch larger pipe for suction. After all connections are made, the ejector is lowered into the water.

Before starting the system for the first time, it must be filled with water. The pump is primed through a special hole. The pipes leading to the ejector must also be filled with water.

Before starting a pumping station with an ejector, it is necessary to fill the surface pump with water, as well as all pipes connected to the ejector

Initial launch and further operation

It is recommended to perform the initial start-up of the pumping station according to the following scheme:

1. Pour water into the pump through the special hole.
2. Turn off the tap through which water flows from the pumping station to the water supply system.
3. Turn on the pump for about 10-20 seconds and turn it off immediately.
4. Open the tap and bleed some of the air from the system.
5. Repeat the cycle of short-term pump on/off in combination with bleeding air until the pipes are filled with water.
6. Turn on the pump again.
7. Wait until the accumulator is filled and the pump automatically turns off.
8. Open any water tap.
9. Wait until the water flows out of the accumulator and the pump turns on automatically.

If water does not flow when starting up a system with an ejector, it is possible that air is somehow leaking into the pipes, or the initial filling with water was not performed correctly. It makes sense to check the presence and condition of the check valve. If it is not there, the water will simply pour into the well, and the pipes will remain empty.

These points should also be taken into account when using a pumping station with an ejector, which is started after long-term storage. It is best to check the check valve, the integrity of the pipes and the tightness of the connections immediately.

The lower pipe of the ejector, through which water is drawn, should be protected from contamination using a coarse strainer (+)

If everything is in order, but water does not flow, you need to check the voltage supplied to the pumping station.If it is too low, the pump simply cannot operate at full capacity. You should establish a normal power supply to the equipment, and the problem will disappear.

If an ejector is needed to improve the water pressure in the system, and not to increase the depth of water intake, you can use the homemade ejector model described above.

But it does not need to be immersed in water; it can be placed in a convenient place near the surface pump. In this case, the ejector will work approximately the same as the built-in industrial production model.

Conclusions and useful video on the topic

This video discusses in detail the issue of the suction depth of a surface pump and options for solving the problem using an ejector:

The principle of operation of the ejector is clearly demonstrated here:

An ejector is a simple but very useful device. This is a convenient and practical way to improve the performance of pumping equipment in a private home. But the installation of the ejector, especially the remote model, must be done correctly; this is the only way to ensure a noticeable increase in water pressure.

We invite everyone interested in the issue of choosing and connecting an ejector to join the discussions and leave comments on the article. The comment form is below.