DIY water injector. Ejector pump: device, types, principle of operation

If desired, you can equip the house with autonomous water supply almost everywhere. But the main problem is the depth of groundwater. If the water mirror in the prepared well is at a level of 5-7 meters, then there are no particular problems, you can use almost any type of pump that is suitable for performance and power consumption. The situation is different with wells, where the water begins much deeper. In this case, the ejector for the pumping station will be able to cope with the task.

Natural restrictions for work are created by atmospheric pressure, water column pressure and the strength of the elements of the pumping station itself. To raise water from a great depth, it is necessary to use a submersible pump or significantly increase the weight and dimensions of the equipment, from which it simply becomes incapacitated and consumes a huge amount of energy. To avoid such problems, it is necessary to facilitate the rise of water by additional means, to push it towards the surface, for which an ejector is needed.

Operating principle

The ejector is structurally very simple device. It consists of the following main components:

• nozzle;
• suction chamber;
• mixer;
• diffuser.

The nozzle is a branch pipe, the end of which has a narrowing. The liquid flowing out of the nozzle instantly accelerates, escaping from it at great speed. According to Bernoulli's law, a fluid flow at high speeds exerts less pressure on the environment. A jet of water from the nozzle enters the mixer, where it creates a significant vacuum along its boundaries.

Under the action of this vacuum, water from the suction chamber begins to flow into the mixer. Further, the combined liquid flow through the diffuser enters further through the pipes.

In fact, in the ejector there is a transfer of kinetic energy from a medium with a higher speed to a medium with a lower speed. How can this be used in combination with a pump?

The ejector is included in the pipeline from the well to the pump. Part of the water that it raises to the surface returns back to the well to the ejector, forming a recirculation line. Escaping at great speed from the nozzle, it takes a new portion of water from the well, providing additional vacuum in the pipeline. As a result, the pump spends less energy to lift fluid from great depths.

By means of a valve installed in the recirculation line, it is possible to regulate the volume of water flowing back into the water intake system, and thereby adjust the efficiency of the entire system.

The excess liquid, not involved in the recirculation, is supplied from the pump to the consumer, determining the productivity of the entire station. As a result, you can get by with a smaller motor and a less massive pumping part, which will last longer and consume less energy.

The ejector also makes it easier to start the system, a relatively small volume of water is able to create a sufficient vacuum in the pipeline and initiate the initial water intake so that the pump does not idle for a long time.

Device and types of stations

Pumping stations can be equipped with an ejector in two ways. In the first, it is structurally part of the pump and is internal. In the second case, it is implemented as a separate external node. The choice of layout depends on the requirements for the pumping station.

Built-in ejector

At the same time, water intake for recirculation, as well as the creation of pressure in the ejector, is created in the pump itself. This arrangement allows to reduce the dimensions of the installation.

The pump with an internal ejector is practically not susceptible to the presence of suspension in the form of sand and silt. It is not necessary to filter the incoming water.

The station is used to draw water from a depth of up to 8 meters. It creates enough pressure to provide a large farm, where water is mainly used for irrigation.

The disadvantage of the internal ejector is the increased noise level during operation. Its installation is best done outside a residential building, best in a separate utility room.

The electric motor is selected obviously more powerful so that it can also provide a recirculation system. However, this comparison is relevant only in a situation with a well depth of up to 10 meters. At greater depths, pumps with an ejector simply do not have an alternative, except perhaps only a submersible type, for which it is required to equip a well with a large diameter.

Remote ejector

With a remote ejector device, an additional tank is installed separately from the pump, into which water enters. It creates the necessary pressure for operation and additional vacuum to lighten the load on the pump. The ejector itself is connected in the submersible part of the pipeline. For its operation, it is necessary to lay two pipes into the well, which imposes some restrictions on the minimum allowable diameter.

Such a constructive solution reduces the efficiency of the system to 30-35%, however, it allows extracting water from deep wells up to 50 meters, and also significantly reduces the noise of the operating pumping station.

It can be located directly in the house, for example in the basement. The distance from the well can be up to 20-40 meters without reducing efficiency. Such characteristics determine the popularity of pumps with an external ejector. All equipment is located in one prepared place, which increases the service life, it is easier to carry out preventive maintenance and configure the system.

Connection

In the case of an internal ejector, if it is included in the design of the pump itself, the installation of the system is not much different from the installation of an ejectorless pump. It is enough just to connect the pipeline from the well to the suction inlet of the pump and equip the pressure line with related equipment in the form of a hydraulic accumulator and automation that will control the operation of the system.

For pumps with an internal ejector, in which it is fixed separately, as well as for systems with an external ejector, two additional steps are added:

• An additional pipe for recirculation is laid from the pressure line of the pumping station to the inlet of the ejector. The main pipe is connected from it to the suction of the pump.
• A branch pipe with a check valve and a coarse filter for drawing water from the well is connected to the suction of the ejector.

If necessary, a valve for adjustment is installed in the recirculation line. This is especially beneficial if the water level in the well is much higher than the pumping station is designed for. You can reduce the pressure in the ejector and thereby raise the pressure in the water supply system. Some models have a built-in valve for this setting. Its placement and method of adjustment is indicated in the instructions for the equipment.

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 delivers it to the system too slowly and with low pressure.

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

We will show you how to choose the right unit and install it without the help of specialists. And also we will give a step-by-step instruction on the manufacture and connection of a home-made ejector. All stages of work are accompanied by visual photographs.

The deeper the water is, the more difficult it is to raise it to the surface. In practice, if the depth of the well is more than seven meters, it is difficult to cope with its tasks.

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 characteristics of a surface pump to an acceptable level and at a much lower cost.

The ejector is a small device, but very effective. This assembly has a relatively simple design, it can even be made independently from improvised materials. The principle of operation is based on giving the water flow an additional acceleration, which will increase the amount of water coming from the source per unit of time.

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Many owners of private houses or garden plots often think about arranging an autonomous water supply system. However, not everyone knows how best to do this.

1 How to choose the type of pump?

An autonomous water supply system can be installed in almost any private house and on any garden plot. The only problem in this case will be the depth at which the waters lie. If the water in a pre-prepared well is at a depth of seven meters, then there should not be any difficulties with its extraction. In this case, a pumping unit of absolutely any model is suitable.

The situation is quite different with those wells where the water is at a deeper level. In this case, only a pump with an external ejector can be used. An obstacle to the operation of an ejector water pump will be atmospheric pressure, the level of strength of the individual elements of the water pump itself with an ejector.

To carry out the process of raising water from a great depth, the so-called steam jet vacuum pump should be used, or the size or mass of a surface water pump with an external ejector should be increased several times. However, this can lead to the failure of the steam jet water pump.

2 What is the principle of operation of the ejector for the pump?

Ejector pumps have an extremely simple design. They consist of the following elements:

1. Nozzle.
2. Diffuser.
3. Mixer.
4. suction chamber.

The nozzle of the ejector pumping device is a branch pipe having a narrow end. The principle of operation of the ejector for a water pump is to instantly accelerate the water flow flowing from the nozzle. In accordance with the laws of physics, a water flow that has a high speed has the least effect on the atmosphere. Water from the nozzle enters the internal mixer, where it is separated along the boundaries. As a result of this separation, water from the chamber begins to flow into the mixer.

After that, the centrifugal flow of water is fed through the diffuser further through the pipes. That is, in the ejector of the water intake installation, the process of transferring energy from the medium with the highest speed to the medium with the lowest speed is carried out.

The ejector is part of the pipeline that runs from the well to the pump. That part of the water that was raised to the surface of the well, after a certain time, begins to flow back into the well, namely to the ejector, resulting in the formation of a circulation line.

Having escaped from the nozzle at high speed, the water takes with it part of the water from the well, thus providing additional discharge in the plumbing system. As a result, pumps use much less energy to lift water from depth.

Thanks to a special valve installed on the so-called circulation line, the process of adjusting the volume of water that is fed back to the intake system can be carried out, and thereby gives additional efficiency to the intake system.

Excess water that did not take part in the circulation process is transferred by ejector pumps to consumers, thus setting the productivity level of the entire ejector pumping station. This helps to get by with engines with the lowest power level, as well as a less massive water intake.

In addition, ejectors help to significantly facilitate the process of starting the pumping system, thanks to them, even a small volume of water can create sufficient vacuum in the plumbing system, thereby initiating the process of initial water intake so that the system does not work, as they say, idle.

2.1 The principle of operation of the ejector (video)

3 What are the types of ejector pumping stations?

Ejectors on the water intake unit can be installed in 2 ways. The first implies that the ejector is one of the constituent elements of the design of the pumping station. In the second case, the ejector is an external node. The choice of a particular option will depend, first of all, on the requirements that apply to the water intake installation.

3.1 Embedded devices

This option implies that the creation of pressure for the ejector is carried out in the installation itself. Due to this, the dimensions of the pumping unit can be significantly reduced. Pumping stations with a built-in ejector are almost immune to the presence of various kinds of small particles in the water.

That is, there is no need to filter the water. This type of water intake installations is mainly used for taking water from a depth of more than eight and a half meters. Allows you to create a pressure of the necessary power to provide a garden plot of large sizes, where water is used mainly for irrigation.

However, pumping stations with built-in ejectors have such a disadvantage as an increased noise level during operation. For this reason, it is not recommended to install this type of water intake in the immediate vicinity of a residential building.

It is best if such an installation is mounted in a separate utility room. The electric motor for this type of pumping installation should be selected in such a way that it can provide the necessary water circulation system.

3.2 External devices

When using an external ejector, an additional water collection tank must be installed separately from the water intake unit. In such a tank, the pressure necessary for the operation of the system and additional discharge will be created, which, in turn, will significantly reduce the degree of load exerted on the pumping unit. The external ejector itself should be connected to the immersed part of the plumbing system.

To ensure the normal functioning of the external ejector in the well, it will be necessary to lay two pipes, however, this may impose certain restrictions on the allowable diameter. This constructive solution, despite the fact that it reduces the efficiency of the water supply system by about thirty-five percent, allows pumping water from a depth of up to fifty meters and significantly reduces the noise level during the operation of the pumping unit.

A water intake station with an external ejector can be located directly inside a private house. For example, in various kinds of basement-type premises. In this case, the distance from the well can be from twenty to forty meters.

It has absolutely no effect on the degree of efficiency. This is what explains such a wide popularity of this type of water intake stations among the population. All equipment is located in one place, which significantly increases the operating period, greatly simplifies the process of carrying out various kinds of preventive maintenance and setting up the plumbing system.

4 How to connect the ejector?

If you use an internal ejector, that is, it is one of the constituent elements of the design of the water intake station, then the installation process of the system will practically not differ from the installation of a water intake unit without an ejector.

In this case, it will be enough for you to just connect the water supply from the well to the suction hole, and then complete the process of arranging the pressure line with the appropriate equipment in the form of batteries, as well as other automatic devices that are necessary to ensure the functioning of the system.

If you are using an intake unit with an external ejector, or an intake unit in which the internal ejector must be fixed separately, then two more steps will be added to the connection procedure described above:

1. The first stage involves laying an additional pipe, which is necessary for the circulation of water from the pressure line of the water intake to the inlet of the ejector.
2. At the second stage, the process of connecting a special pipe with a coarse filter and a return pipe to the suction hole of the water intake station is carried out.

If necessary, a special valve can be built into the water circulation line, which is intended to adjust the system. This will be beneficial if the water level in the well exceeds that for which the intake unit is designed. It is possible to reduce the power of pressure supplied to the ejector, thus increasing the power of pressure in the plumbing system.

Some water intake station devices have a pre-built valve to make this adjustment.

Let's see what an ejector is. It is worth starting with the fact that it is an integral part of the pumping stationdesigned for pumping water. What is its essence?

The main purpose is to help the pumping station. In such cases, when the water is at a great depth, for example, at a depth of 7 meters, a conventional pump may not be able to cope with the water supply. And then, to solve the problem of pumping water even from such a depth, an ejector is installed to help the pump. In this way, the problem is easily solved. In other words, the device is used to improve the efficiency of the pumping station.

Of course, if the water is too deep, then you will need to use a technique such as a powerful submersible pump.

Device Features

The device of the ejector is very simple, it can even be assembled by hand from ordinary materials. The design of the device consists of such parts as:

• Diffuser;
• Node to offset;
• Water suction chamber;
• Nozzle narrowed down.

The operation of the device is based on Bernoulli's law. When the speed of a certain flow increases, a field with a low level of pressure is created around it. As a result, there is an effect vacuum. The liquid, passing through the nozzle, narrowed downwards according to its design, gradually increases the speed. After that, the liquid, getting into the mixer, creates a low pressure in it. Thus, the pressure of the liquid that enters the mixer through the water suction chamber is greatly increased.

It is also worth noting that for the ejector to work properly, it must be installed on the pump so that some of the liquid that rises with the pump remains inside the device, or rather, the nozzle, creating the necessary pressure constantly. It is thanks to this principle of operation that it is possible to maintain a constant accelerated flow. The use of such a device can significantly save energy.

The main types of ejectors

Depending on the installation, the ejectors may be different. They are usually divided into two main types: built-in and remote. The difference between these types is small, that is, they differ only in the place of installation, however, this slight difference may affect the operation of the pumping station. . Both types have their own advantages and disadvantages..

Built-in, as you might guess from the name, is mounted directly into the pump housing, being its integral part.

Embedded model

The built-in ejector has its advantages:

1. It is enough just to mount the pump itself, without installing additional equipment, while saving space in the well.
2. It is located inside, that is, it is protected from dirt getting inside the device, and this, in turn, allows you to save money on purchasing additional filters.

Of the shortcomings, only a small efficiency can be noted at great depths exceeding 10 meters. However, the main purpose of built-in models is to use them for pumping water from shallow depths. And one more nuance in protecting embedded devices: they provide a powerful and uninterrupted water pressure. Therefore, they are often used for irrigation and other household needs.

Another minor disadvantage may be the high level of pump noise, which is amplified by the noise of the water flow. Such pumps are usually installed outside a residential building.

Remote instrument

A remote, or external, device is mounted on a pumping station at a depth of at least 20 meters. And according to some experts, it is completely necessary to install the device at a distance of half a meter from the pump. That is, it can be placed directly in the well or brought to a water source. Thus, the noise from work will not be a problem for the residents. However, even here there are some nuances. For example, to connect a pump to a source, a pipe is needed so that water can return to the device. The length of the pipe must match the depth of the well. In addition to the pipe for recirculation, a tank is also needed from which water will be drawn.

Steam, steam jet and gas

Steam ejectors are designed to pump gas out of confined spaces and to maintain the air in a rarefied state.

Steam jets, unlike steam jets, use the energy of a steam jet. The principle of operation is based on the fact that the flow of steam leaving the nozzle carries with it at high speed the flow passing through the annular channel around the nozzle. Similar station used for pumping water from ships.

The air or gas ejector is used in the gas industry. During operation of the device, a low-pressure gas medium is compressed, compression is achieved due to high-pressure gas vapors.

Vacuum fixtures

The operation of vacuum ejectors is based on the Venturi effect. They are multi- and single-stage. Compressed air enters the device and passes through the nozzle, and this leads to an increase in dynamic pressure and a decrease in static pressure, that is, a vacuum is created. Therefore, compressed air entering the ejector, mixes with the exhaust air and exits through the muffler.

In multi-stage ejectors, unlike the first type, the vacuum is created not in one, but in several nozzles, which are located in one row. Thus, the compressed air passes through the nozzles and exits the muffler. Advantage of the second kind is that when using the same volume of air, greater productivity is provided than in single-stage ones.

Difference from injector

Both of these devices are jet, that is, for the suction of liquid and gaseous substances.

An ejector is a device in which kinetic energy is transferred from the working medium to a non-working, that is, passive medium, by means of their displacement.

Injector - device where gases and liquids are compressed.

The main difference between these devices lies in the way energy is transferred to the passive medium. For example, in the injector, the supply occurs due to pressure, and in the ejector, the supply occurs due to the creation of a self-priming effect.

Pumping stations are in high demand among the population when arranging individual water supply due to their versatility and reasonable cost, their only serious drawback is the small depth of water intake, not exceeding 9 meters. For this problem, there is a simple engineering solution based on the physical Bernoulli's law - an ejector for a pumping station, with a similar device, a surface electric pump is capable of sucking water from deep sources at a distance of a water mirror from the earth's surface of tens of meters.

This device, when used with a surface pump, is useful in cases where the water level of the source with which the surface pump previously worked has fallen for some reason (silting of the well and well, intensive water intake).

At the same time, it should be understood that the price of obtaining a high suction depth is the low efficiency of the electric pump, because part of the raised water is sent back to the suction pipe to increase the kinetic energy of the inlet flow. This factor hinders the use of surface ejector electric pumps for lifting water from great depths - for these purposes, wells are drilled and submersible pumps are used, the head of which in a domestic version can reach up to 200 m.

Rice. 1 The device and appearance of the ejector for the water station

An ejector is a device in which two media are connected in a mixing chamber, while one of them moves at high speed and is fed through a narrowed nozzle, and the second fills the chamber naturally. The flow leaving the nozzle with acceleration transfers its kinetic energy to the moving medium, which is then carried away from the suction point. Also, a reduced pressure is created in the zone at the exit of the narrow section of the nozzle - this leads to the fact that the transported medium is simultaneously sucked in by the ejector.

The moving and accelerating medium can have a different physical state; in jet pumps, air or steam is supplied through a narrow nozzle, which heats the water flow and pushes it out at high speed.

Rice. 2 Ejector design

What is an ejector and why is it needed

The design of the ejector is not very complex, its main elements are:

• Nozzle. It is a cylindrical branch pipe with a conical narrowing at the end. According to Bernoulli's law, as the cross section of the pipeline decreases, the pressure in it becomes lower, and the speed of the passing flow increases. Thus, there is a movement of the transported flow with high pressure into the low pressure area (suction) and at the same time it is pushed out by a jet of water, moving at high speed (transfer of kinetic energy).
• suction pipe. Through this element of the ejector, the transported liquid enters it, usually its diameter exceeds the size of the inlet pipe of the nozzle.
• Mixing chamber. In this node, two flows collide, while the kinetic energy from the auxiliary is transferred to the main one.
• Neck. After mixing the two streams, the liquid enters the narrowed part, where its speed increases.
• Diffuser. The element has a cone-shaped expansion at the end, as a result of which the pressure of the liquid at the outlet increases, and the flow rate decreases. The cross section of the diffuser is designed for connection to a pressure pipeline of standard diameter.

Rice. 3 Centrifugal pump - interior

The use of an ejector in domestic pumping stations is justified only in exceptional cases - when it is used, depending on the depth of immersion of the suction pipe, the efficiency drops by 50 - 70%, which leads to unjustified waste of electricity. Therefore, to draw water from great depths, everyone uses submersible electric pumps and drills special wells for them. This is also more efficient because the efficiency of submersible pumps is higher than surface pumps, which spend part of their energy on suction and lifting the water column to the impeller (65% to 50% ratio).

On the pumping equipment market, there are still surface centrifugal electric pumps with built-in or remote ejectors, and in order to answer the question of why an ejector is needed in a pumping station, you should consider options for its use:

• Dry summer or long periods of rainless weather. In this case, the static water level in the well or well decreases, and at a mark of more than 9 m from the surface, a conventional centrifugal surface pump will not be able to raise it. In this situation, you can connect an external ejector and use the source for some time with a loss of performance until the static level rises.
• If there is a one-time intensive water intake. The situation may arise if a shallow source has a low flow rate (replenishment rate), but it is necessary to raise a large volume of water, for example, for a bath, filling containers for irrigation and other household needs in a private house, leading to a drop in level.
• Operational lowering of the water mirror in the source. Any well on sand has a short service life and silts up over time, the same problem occurs with wells, so the static water level in them drops. Installing an ejector will allow you to raise water from depths of more than 9 meters before cleaning the source or solving problems by other methods.

Rice. 4 Ejector pumping stations

What are the pumping stations

The pumping station is a structure assembled into a monoblock, the main part of which is a centrifugal electric pump located above the hydraulic accumulator tank, its mandatory elements are a pressure switch and a pressure gauge fixed on a five-inlet fitting.

The principle of operation of a centrifugal electric pump is to supply the suction liquid to the center of the impeller with blades, which, when rotated, due to centrifugal force, push it out through the side outlet pipe.

A standard centrifugal pump has an inlet in the center of the hydraulic compartment and an outlet located perpendicular to its axis in the side, but there are pumps with a different design.

Rice. 5 Built-in ejector - diagram

Stations with built-in ejector

Pumping stations with a built-in ejector incorporate a centrifugal electric pump, in the hydraulic part of which an ejector unit is located. The principle of operation of such a system is quite simple - the suction water enters the centrifugal impeller, which throws it out through the side pipe. At the same time, part of the liquid, to which the rotation of the wheel has given kinetic energy, is directed through the ejector channel to the nozzle and is pushed out of it under pressure. The flow accelerated due to the narrowed part of the nozzle mixes with the transported one, transferring its energy to it, and at the same time drawing it in due to the reduced pressure at the outlet. Thus, a significant increase in the immersion depth of the suction pipe is achieved, which in some models reaches 50 meters.

A distinctive feature of such pumps is the inlet, displaced relative to the central axis (in conventional centrifugal electric pumps, such an arrangement is also not uncommon), such units are very rare in the composition of pumping stations due to the above reasons (low efficiency).

Rice. 6 Electric pump device with built-in ejector

Remote ejector stations

A pumping station with a remote ejector has a significant advantage over equipment with a built-in ejector unit - it can operate in normal mode, we raise water from a depth of no more than 9 meters, and if necessary, you can always connect a device to increase the suction depth.

To do this, in the hydraulic part of the body there are two holes of different diameters with standard sizes of 1 1/2 and 1 inch, a pressure pipe is connected to the larger one, and a recirculation pipe is connected to the second one, supplying water to the ejector nozzle. The ejector assembly itself is placed in a water intake source along with pipelines. Since without supplying liquid to the ejector, it will not rise from a great depth, the entire system is filled with water before starting work.

In appearance, electric pumps with a remote ejector differ from standard models by the presence of two adjacent holes in the hydraulic compartment of the housing. A pumping station with an external ejector is produced by many domestic and foreign manufacturers, the Marina model from the Italian company Speroni is the most famous, and other Italians are also often found on the market: Aquatica, Quattro Elementi, domestic Unipump.

Rice. 7 Remote ejector station and its connection

How to make an ejector yourself

When a standard pumping station stopped sucking water during operation due to a lowering of the water table, it can be lowered by digging a hole of the required depth in the ground - there are no other ways to increase the suction depth. It is pointless to make a home-made ejector according to any drawings, to purchase and install it - the part cannot be connected to a housing in which there is one inlet for the pressure pipeline instead of the two required for the operation of the ejector assembly.

If an ejector pumping station was purchased, and the assembly was lost or broken, you can make an ejector with your own hands from parts of plumbing fittings and fittings.

A similar design scheme is shown in Fig. 8, its main components are:

• Tee(one). The part serves to connect the inlet pipes for two water flows and at the same time is a chamber in which they are mixed with the transfer of kinetic energy to the transported one. At the outlet of the tee, instead of a diffuser, an adapter is installed to connect the pressure pipeline.
• Union(2). The part replaces the nozzle in the standard model and is designed to accelerate the recirculating water flow. When installing it, the length of the fitting is chosen so that the flow coming out of it is on the central axis of the transported one.
• corners(6, 7). Necessary for connecting the recirculation pipeline and placing the ejector in a vertical position, the angle 7 has a small inner diameter due to the fact that the return flow is always fed into the ejector through a pipeline of a smaller cross section than the pressure one.
• Injection(5). Water from the source enters the ejector through this part, the nut at the end is for attaching the water filter.
• Adapter(4). The part is necessary to connect the pressure pipeline entering the pumping station.

Before assembly, grind the hexagonal part of the fitting to a cone-shaped state, shorten it to the desired length or lengthen it with a piece of vinyl chloride tube. After that, the entire structure is assembled, first screwing in the fitting, and then the rest of the parts with sealing the threaded connections with flax, plumbing thread, FUM tape.

Rice. 8 Homemade ejector

Water pumping stations for individual water supply with a built-in or remote ejector to increase the suction depth are rarely used in everyday life due to a very low efficiency of about 15%. The purchase of such devices is advisable in cases where the level of the water table is likely to temporarily drop below the maximum allowable mark of 9 m due to various circumstances - large volumes of water intake, drought, frequent siltation of the source with a decrease in water level.

Video

The principle of operation of the ejector

Aurora ejector pumping station, description