Hydraulic accumulators for pumping stations. Pumping station without accumulator: description, device and reviews

Well pumps

Purely technically, the water supply system can work without a hydraulic accumulator. Why, then, experts strongly recommend not to refuse to use this device?

The permissible pressure in the system is 1.5 to 3 atmospheres. If the readings are outside the specified limits, the pressure switch will respond and the pump will shut down.

The pump will start working again only when the pressure normalizes. Pressure jerks that accompany these processes adversely affect both the electrical and mechanical elements of the device. The accumulator is able to equalize the pressure in the process of using the pumping station.

The scheme of action is quite simple. Reaching a pressure of 3 atmospheres, the pump naturally shuts down, but the system continues to expend water from the accumulator until the pressure drops to the limit required to resume pump operation. The time interval between switching on and off is significantly reduced, which determines the functionality of the entire system.

Different models of hydraulic accumulators give unequal indicators of the maximum number of pump starts per hour. For example, when operating a household unit with a capacity of 24 l, the pump will be activated about 20 times per hour. The larger the capacity of the accumulator, and in some industrial units it can reach 500 liters, the less the number of starts per hour.

It is important that the pre-inflated air pressure in the accumulator is several tenths less than the pressure level required to turn on the pump. Deviation from this requirement upwards will lead to a noticeable reduction in the interval between switching the pump on and off. Failure to comply with the downward direction is fraught with rupture of the membrane, which naturally excludes the accumulator from the water supply system.

Why do I need a hydraulic accumulator? Video

Technologies in the field of pumping equipment today allow a private homeowner to completely take on the task of providing water. Models of pumping stations with compact dimensions cover the needs for irrigation, and powerful units with increased productivity realize the rise of water to the second floor. To maintain a stable pressure in the circuits, developers are increasingly using a hydraulic accumulator. This solution has many obvious advantages, but such power additions are not always appropriate from the point of view of operational rationality. In turn, a correctly selected pump station without a hydraulic accumulator can provide the target with water with minimal financial and technological costs.

General information about pumping stations

The principle of operation of water pumping stations is in many ways similar to conventional pumps. The difference lies in the use of automatic means of process control and the possibility of additional equipment - primarily due to the same accumulator. But even models without a hydraulic tank outperform conventional pumps in terms of power. For example, on average, 2-5 m3 / h is required to supply a private house. In this range, there is a pumping station for a private house without a hydraulic accumulator, introduced into a well or a well. A significant difference is the strong elemental base, enclosed in a stainless steel case. It is models without a hydraulic accumulator that are given more attention in this sense, since they work at high loads without additional insurance against hydraulic shock.

How does it work without a hydraulic accumulator?

The design of the station is formed by a whole complex of functional elements. Without exception, all models are equipped with a pump, which ensures the pumping of water from the source. Unit functions are controlled by relays. At least through it, the user can adjust the sufficient pressure. To control the pressure, a pressure gauge is used, which is usually included in the basic package. Also, without fail, the pumping station without a hydraulic accumulator includes an electric cable, grounding terminals and a socket for connecting to the network. The above components are not always delivered complete. If you wish, you can build a station from different components - the main thing is that they correspond to each other in terms of characteristics.

Station assembly

The assembly process is carried out at the future site of operation, when a water supply line from a source — a well or a well — has already been organized. Complete nozzles for input and output are connected to the pump. Then hoses are connected to them - respectively, from the source of the intake and from the water supply circuit to the place of use. The return lines may be several depending on the design of the station. Properly assemble a pump station with your own hands without a hydraulic accumulator for several consumers is possible only taking into account the load on the power grid. As waste channels increase, productivity will increase. Therefore, it is recommended to ground with a residual current device. Such devices are usually present in the kit, as well as control fittings with sensors, measuring instruments and automatic devices. The latter are introduced into the infrastructure of the station at the final stage of installation.

Operation Nuances

It is advisable to place the assembled unit in the hozblok on a stable flat surface. Both connection lines (to the source of water intake and the power supply network) must be isolated and protected from external influences. During pumping, the pump will not cycle for a supply of water, as is the case with a hydraulic accumulator. The fence will take place directly to the point of consumption, which increases the responsibility of the control equipment. At the same time, the operation of a pumping station without a hydraulic accumulator involves automatic shutdowns and turns on. Threshold values \u200b\u200bcan be set via the control relay, but in this case it is important to correctly assess the load on the station, not counting on the support of the buffer unit.

Positive feedback on stations without accumulator

Basically, users indicate an ergonomic design that is simplified compared to pumps supplemented with a hydraulic accumulator. These are small and lightweight units that do not cause any special problems in installation and operation. The possibility of convenient placement of such models in pits with a frame base is noted. But this aspect will depend on in what form factor the pump station is made without a hydraulic accumulator. Reviews of downhole modifications, for example, emphasize the variety of mounting options in the vertical and horizontal planes. Stations with a hydraulic accumulator do not provide such opportunities - as a rule, only a single horizontal placement is allowed.

Negative reviews about stations without accumulator

There are also many weaknesses in this type of model. In practice, equipment owners have noted modest performance. Moreover, the use of the maximum resource to fill the lack of power is not allowed. Here we are talking about a drawback in the form of the risk of water hammer. These are less protected structures, therefore, in the process, it is desirable to establish average operating parameters. On the whole, a pumping station without a hydraulic accumulator is perceived on the market as an aging solution. This is partly due to performance limitations, but there is also a process of reducing optional content, as manufacturers lose interest in the segment.

Conclusion

The inclusion of a hydraulic accumulator in the design of pumps undoubtedly raised the possibility of organizing private water supply to a new level. This also applies to increasing the reliability of equipment, and increasing its power indicators. Nevertheless, there are tasks that pump stations without a hydraulic accumulator are better able to cope with. The price of such units, which averages 7-15 thousand rubles, also acts as an important factor in favor of this choice. For example, for 10 thousand, you can buy a high-quality installation, the capabilities of which are enough to water the garden and cover household needs in the country. A hydraulic accumulator for such a system will not bring much benefit, but it will certainly become another item of energy consumption. Ordinary stations can serve and a private house, but in this case you will have to turn to the most productive models in the segment.

Let's analyze the seven most common myths about accumulators and their functionality.

Myth 1. The hydraulic accumulator is designed to create constant pressure in the water supply system.

Such a phrase can often be found in descriptions of hydraulic accumulators. Variations - the accumulator maintains a constant pressure, etc.

To begin with, the membrane (rubber bulb) in the metal casing is not able to create any pressure, either constant or "variable". Pressure is generated only by the pump. What pressure the pump provides, the same pressure will be in the accumulator. The only thing that can be said is that the accumulator, in the absence of water consumption, supports the pressure created in it and contributes to its gradual decrease with the beginning of the tapping and a smooth increase after closing all the taps. Those. without it, the pressure would change instantly, and with it changes smoothly, due to a change in hydraulic volume by stretching-compressing the membrane. This is the main point of its use. For the correct functioning of the system with the ubiquitous pressure switch, it is precisely a smooth change in pressure that is provided with the help of a hydraulic accumulator.

Talk about constant pressure in a standard system with a pressure switch and a hydraulic accumulator is not necessary at all. The whole point of the functioning of such a system is that the pressure is constantly changing, due to which the pump is automated by means of a pressure switch. Constant pressure can only be at a constant flow rate, but as soon as the water flow rate changes (opened or closed an additional tap), the pressure instantly changes. All that a hydraulic accumulator can do is set inertia for the system, which is what is actually required of it. Constant pressure in variable flow systems can only be achieved by using a frequency converter, when the speed of the pump changes depending on the flow of water.

Myth 2. The larger the accumulator volume, the better.

So much the better for what? For the accumulator itself, for the reliability of the system, for the pump? A large hydraulic tank is more expensive, takes up more space, the cost of replacing the membrane is higher. Some cons.

But there is a certain logic in the statement and it consists in the following: the larger the volume of the hydraulic tank, the less often the pump will turn on. And the less often the pump turns on, the longer it will work, since the resource will be saved (the starting mode of the electric motor is the most intense - a jump in the starting current, a high starting moment, an increased load on the pump parts).

However, on the other hand, it is logical to assume that there is a certain limit on the volume of the accumulator, which must be stopped. After all, it doesn’t occur to anyone to buy a thousands of liters of hydraulic accumulators for a private home. Although with such a tank, the pump can turn on only once or twice a day or not at all. Do not forget that the useful accumulator volume is about 30%.

The misconception is that even if we reduce the number of pump starts per hour by half (increasing the volume of the accumulator), the pump will not ultimately last twice as long. Even knowing the number of starts per hour, we cannot estimate the total operating time in each cycle, which is much more important for the resource. Similarly, if you use the pump for only six months, for example, in the summer season, you do not need to expect that the pump will last two times longer than that of a neighbor who uses the pump all year round.

Engine manufacturers do not give a certain limit on / off for the entire period of operation, after which the engine fails or requires repair. The engine life is affected by the total operating time and thermal conditions. But at the same time, it is really important that the number of short-term pump starts per hour does not exceed the values \u200b\u200bspecified by the manufacturer (these data are in the technical documentation for the pump). This is the main criterion by which the volume of the accumulator is selected. And if the pump is equipped with a soft starter, then the number of these same starts can be increased. Those. tank volume can be reduced.

Myth 3. All accumulators are the same. If it makes no difference, why pay more?

If we pay attention only to the external aspect, then it is difficult to disagree with this statement. If we are talking about standard hydraulic tanks with a replaceable membrane, then externally they really look alike like twin brothers.

But as often happens, the most important thing is inside. Although accumulators have a really simple device, even here there is a place for nuances. That is why in some hydraulic tanks air escapes, and the membrane fails after a year or two, while others hold pressure and last much longer.

Myth 4. The accumulator needs to install an air vent.

The water supply system (not to be confused with the heating system) can do without an air vent without problems. Air bubbles with correctly laid pipes are removed through the tap during drawdown. And with incorrectly laid pipes (with the possibility of air pockets), the air vent will not save the case.

Note that pressure switches can also work with air (for example, installed on compressor equipment).

You can install an air vent for complacency, but this does not give a real effect.

Myth 5. All accumulators are blue.

Helping the buyer to navigate the variety of expansion tanks, most manufacturers actually produce accumulators (expansion tanks for water supply systems) of a blue color. The standard color association works, which is nothing bad.

However, the accumulator is painted only on the outside, so there are no technological problems for color change.

Hydraulic accumulators are an integral part of many domestic and industrial pumping stations (come with them in the kit). Manufacturers of pumping equipment do not independently produce expansion tanks and purchase them from specialized enterprises. For marketing purposes, these tanks can have not only a different nameplate with a name different from the original (which is not uncommon today), but also a different color. At the request of the customer, the manufacturer of hydraulic accumulators can paint them in the factory in any color.

For example, Grundfos used green accumulators for a long time, Pedrollo had red tanks, and DAB used white ones. Moreover, even different consignments of goods could be of different colors. Sometimes the choice of accumulator color depends on the general color scheme of the pump manufacturer.

The color itself does not in any way affect the technical characteristics of the accumulator and, by and large, can be anything.

Therefore, if your green hydraulic tank from the Grundfos station is out of order, it makes no sense to look for a tank of a similar color.

Of course, blue is the most common accumulator on the market, but not the only one.

Myth 6. For the winter, from the accumulator it is necessary not only to drain all the water, but also to bleed air.

Indeed, if you plan to still use your accumulator in the next year, then it is necessary to drain the water from the tank. However, there is no need to bleed air after draining the water. The membrane is strongly compressed under air pressure and squeezes out all the water.

It is believed that the membrane is easier in the free state and it is better to remove it for the winter. Without arguing or even not taking into account labor costs, we will give only one important counterargument. All hydraulic accumulators go on sale with a preliminary factory air injection, which strongly deforms (compresses) the membrane, since in the unconnected state there is no back pressure of water. In this form, a new tank can be stored for more than one month, or even a year, until it finds its owner. And there’s nothing wrong with that. The hydraulic accumulator is installed, the air pressure is controlled, the system is launched and everything works great.

Our experience in operating domestic water supply systems indicates that the positive effect of the complete emptying of the air cavity in the winter period has no practical confirmation.

Of course, you can go to extremes, take apart half of the water supply system for the winter and a hydraulic tank in addition. Rinse, dry and fold everything at home in a warm place. But this option is best left to the "experts."

Myth 7. It is better not to replace the membrane, but to replace immediately the whole accumulator.

When the membrane fails, it is necessary to decide whether to replace the membrane alone or to replace the entire accumulator.

Want to extend your membrane life? Remember to control the air pressure.

It is logical that the decision is made on the basis of comparing the cost of the new membrane and the entire accumulator assembly. For some expensive European brands, the cost of the membrane is about 60-70% of the total cost of the goods. Of course, this is not the real cost of the membrane, but the impudent policy of the manufacturer, trying to make money on spare parts and service, which is quite common today. In addition, it is far from always possible to find a similar replacement, since manufacturers can specifically manufacture membranes with a non-standard neck. Therefore, it is not surprising that the buyer decides to purchase new equipment.

And in what cases is it justified to assemble the pumping station from disparate parts that can be bought at the store.

Why assemble the pumping station yourself.

First of all, it seems to me that a pump station should be assembled on its own if you already have some of its components, usually the most expensive. This is a pump and a hydraulic accumulator. Because the cost of the pump is about half the cost of the pumping station, respectively, the accumulator is about a third. That is, it makes no sense to buy a new pumping station if your accumulator was crushed in the winter or the pump burned out for some reason. You can buy both, and the other separately, and just replace what you have broken, the benefit of the pump fasteners and the accumulator mounting platform, as a rule, are standard and you can easily connect one to the other.

Another reason to assemble a pumping station yourself can be a mismatch of your requirements and the characteristics of the equipment of the finished pumping station. For example, you need a pump with a greater pressure or flow rate than the pump stations offered to you, and what suits you according to its characteristics does not suit you - in terms of cost or reliability. Or the dimensions of the pumping station are too large for the place where you are, or you are not satisfied with the capacity of the accumulator, well, etc. Just need to keep in mind that the total cost of the pumping station may well be much more than what you planned.

The third, most common option, when you are forced to assemble a distributed pumping station because of the very. As a rule, in this case they use a powerful submersible pump, and the accumulator with the automation unit is put somewhere at home.

Is the accumulator really needed?

A reasonable question: is it possible to do without a hydraulic accumulator? In principle, this is possible, but with a conventional automation unit, the pump will turn on and off very often, reacting even to a small flow of water. After all, the amount of water in the pressure pipe is small, and the slightest flow of water will lead to a rapid drop in pressure and the same rapid increase when the pump is turned on. It is due to the fact that the pump does not turn on for each of your "sneezes", they put a hydraulic accumulator, at least a small one. Since water is a non-compressible substance, air is pumped into the accumulator, which, unlike water, is well compressed and acts as a kind of damper that regulates the accumulation and flow of water. If there is no air in the accumulator or too little, then there will be nothing to compress, that is, there will be no accumulation of water.

Ideally, the capacity of the accumulators should be only slightly less than the debit of your water source, and the pump, in this case, will only be switched on when some, rather decent supply of water is used up, i.e. very rarely, but for a long time. But then it will be very expensive.

Now on sale are pumping stations with improved automation units with built-in dry run protection, which smoothly start and stop the pump, and adjust its power depending on the set pressure. It is believed that the accumulator, in principle, they do not need. But all this works well only in the absence of power surges, which our outback and holiday villages cannot boast of. And, unfortunately, stabilizers do not always save from this disaster. In addition, the price of such a station is very often much higher than usual, which, as it seems to me, does not justify itself.

Ready-made automation systems.

Wistan.

Of all the ready-made automation systems for pumping stations, our domestic development Vistan, which is intended exclusively for the organization of a pumping station based on a vibration pump, stands out especially. I am not a supporter of the use of vibration pumps in the water supply systems of private and summer cottages, but I can not help but pay attention to this device because of the great popularity of the "Kids", "Brooks", etc. in the post-Soviet space.

On the Internet there are a lot of flattering reviews about this device. In life, unfortunately, not everything is so rosy. So, briefly.

Advantages:

- Special design for vibration pumps;

- Automatically maintains system pressure at a level of 1.5-2.0 bar;

- Has built-in protection against dry running;

- Has a built-in voltage stabilizer, can work with voltages from 160 to 250 volts;

- It can work without a hydraulic accumulator, smoothly changes the power of the pump;

- Soft start and stop of the pump;

- Has protection for excess of electric current: 5 amp fuse;

- Automatically resumes operation when parameters are restored: mains voltage, the appearance of water pressure at the pump head (dry running).

- Ease of mounting and disassembling the circuit: the manufacturer recommends using a flexible ½ inch eyeliner.

Disadvantages:

- The pump must create a pressure at the inlet of the device of at least 3.0 bar: not every vibration pump is capable of this, given the difference in height between the water mirror in the well (well) and the location of Wistan.

- Water consumption is limited by the internal cross-section of the flexible eyeliner, or you need to put a hydraulic accumulator.

- Dry running protection has been solved in a peculiar way: the device switches off the pump if the inlet pressure does not rise above 0.8 bar in 10 seconds. Those. there is actually water, and the pump pumps it properly, it just doesn’t have enough strength to raise the pressure to the required level.

- There is no way to regulate the pressure in the system.

- The high price of the device compared to the cost of vibration pumps. The cost of the Wistan + Pump set is comparable to the cost of a finished pump station of not the worst quality (and Chinese, one and a half times cheaper).

In general, this option of organizing a pumping station is suitable for summer residents accustomed to their vibrational pumps and not spoiled by the benefits of civilization in the country. In addition, the system is easy to assemble in the spring before use and disassemble in the fall, taking the entire farm with you to the city and not being afraid that it will be stolen or torn by frost. For a more serious water supply system at home, this device, however, like use, is hardly suitable.

Automation unit for centrifugal pumps.

To organize a pumping station on the basis of, whether immersed or surface, an automation unit is needed. The simplest thing is to assemble it yourself using purchased items: a collector, a pressure switch, and a pressure gauge. But you can buy a ready-made unit, on which all this will already be installed. It remains only to install it on the pump head in a convenient place for maintenance.

Various firms offer a wide variety of such units, differing in configuration and cost. The simplest and most inexpensive, include only the necessary elements mentioned above. Blocks in which a dry-running sensor is added will be slightly more expensive. The automation units are considered to be the most sophisticated, which independently, by adjusting the pump power, maintain a given pressure in the system, and also have several (up to three) protections against various unpleasant things (dry running, overload of the pump, rupture of the pressure pipe).

Collector.

Actually, everyone is free to make their choice. It is easier for someone to assemble such a block themselves, for someone it is easier to buy it. It seems to me that the only drawback of such blocks, except for the price, is precisely their blockiness. Those. if something breaks down as part of such an automation unit, then the entire unit will have to be changed, and this is sometimes expensive.

Schemes of pumping stations.

The most common scheme of a pumping station is when all its elements are assembled together, as one of the readers wrote: “pump on a barrel”. In this case, the automation unit is placed on the pump head, and water is discharged to the hydraulic accumulator through a separate pipe or flexible connection. It turns out that you can put a pump and a hydraulic accumulator (GA) in different places, simply replacing the branch to the GA with a longer one.

But the best option would be to put the automation unit on the GA, connecting the collector of the unit with the pump pipe. Then we get a distributed pump station, where the pump can stand, for example, in a well (or in a well for a submersible pump), and the pump is in a warm house.

Continuing to improve our circuit, you can find the most convenient place for the automation unit. I think the distribution manifold is such a place cold water, where the automation unit will maintain constant pressure (after all, this is exactly what we need). The hydraulic accumulator, in this case, can be placed under the bathtub or in any other free place in the bathroom, and the pressure pipe will come from the pump. The pump itself can be put closer to the source of water supply and away from the house, so as not to hear its noise, or buy a submersible pump (again, no noise in the house).

Hello, dear readers of "San Samych." It seems to me that there is no need to repeat the common truth that the pump is the "heart" of the water supply system ...

What is a pumping station? This is a set of equipment that maintains a certain water pressure in the water supply system. At the same time, water supplies the water supply system constantly. For example, a water supply network that supplies a house with water from a well using a pump. The pump itself cannot be called a station, because if you turn off the power supply, there will be no water in the water supply. And the station provides it constantly. Recently, pumps, which include a hydraulic accumulator, have come to be called such stations. This storage tank with a membrane inside creates not only a certain amount of water, but also water pressure. Is there a pump station without a hydraulic accumulator?

Storage tanks for water supply

Of course it does. It is only necessary to create the necessary conditions so that water under a certain pressure is always present in the water supply network. Therefore, a storage tank of any volume is attached to the pump installation, in which a float level sensor must be installed. The latter is responsible for shutting down and turning on the pump device if the water in the tank accordingly exceeds or exceeds the set level.

There are two layout schemes for the storage tank.

It is installed anywhere, usually the room where the water treatment system, for example, is mounted. But such a scheme does not make it possible to pump water above its level in the tank, so another pump is included in it, which will pump water from the storage tank to consumers.
The second scheme is the installation of the tank above the level of consumer location. In this way, the problem of pressure in the water supply network is solved. The principle of connecting vessels, long known to modern physics, will work here. Therefore, the storage tank is usually installed in the attic.

Attention! If the attic is an unheated room, then the container will need to be insulated.

By the way, the second water supply scheme without a hydraulic accumulator is still quite popular today. Indeed, with its help it is possible to organize a water supply system with a large volume of water, many times larger than with a hydraulic accumulator. True, you will have to calculate everything very accurately, because a tank with a filled tank is a huge weight acting on the floors of a house. Therefore, you must be sure that the supporting structure of the building will withstand such a mass.

Diagram of a pumping station without a hydraulic accumulator

In principle, the scheme is quite simple. Regardless of which pump will be used in the home water main (submersible or surface), the source itself must first be protected from silt and dirt from the source of water intake. Therefore, a strainer is installed at the very bottom, which will retain large suspended particles.

Further on the scheme goes either the pump itself, if it is deep, or the pipeline that will connect the filter to the pump mounted on the surface. In the first case, the same water supply will be stretched from the pump in the form of a pipe or hose. That is, the route will begin directly in the hydraulic structure. Therefore, it is very important to determine the level of soil freezing in the area of \u200b\u200bthe location of a well or well. Starting from this level, it is necessary to insulate the pipeline.

Scheme with additional pump

Now the internal wiring of the water supply. Firstly, it is necessary to think over a water treatment system. Unfortunately, from wells and shallow wells, water will not come into the house very clean. Therefore, the easiest option is to install two filters: rough and fine cleaning. They can easily cope with their responsibilities for water purification, but require that they often change the filter cartridges.

The next element is a storage tank with a float. It connects to the pump through a pipe and an installed filter. After it, the pipe is already being diverted to consumers.

Scheme with a tank in the attic

Storage tank

What is a storage tank? This is a simple container, it can be of various shapes and sizes. It has three nozzles. The upper one is the supply, through it the water enters the tank. The second lower one is discharge, through which water is discharged to consumers. The third, it is also lower, and is located below the second, it is a drain pipe for dirty water and precipitation, which is used in maintenance work.

Conclusion on the topic

So, a pumping station for a house without a hydraulic accumulator is considered the last century. This is probably the case. Indeed, the modern approach to the implementation of an autonomous water supply network is not only capacity, it is the possibility of installing it in a place where it is convenient. And although the accumulator itself should only be operated at positive temperatures, there is no need to install it in the attic. You can use the basement, caisson, any room for this. The main thing is that in it the air temperature does not fall below + 5C. But the system without a hydraulic accumulator has not yet lost ground. Moreover, there is always a choice, which at a price, unfortunately, is not in favor of the new technology.