In most cases, the accumulator is a cylindrical tank with spherical, hemispherical, elliptical, etc. bottoms (this is necessary for uniform distribution of pressure on the walls). Inside, it is divided into two cavities interacting through an elastic membrane: air (gas) and water. For the manufacture of the barrier, various types of rubber are used: natural and synthetic (butadiene, ethylene-propylene, butyl).
Today, two main structural types are used:
- Diaphragm. It has a concentric disc-shaped shape and is attached along the perimeter of the tank in its equatorial plane;
- Pear-shaped. It resembles a balloon in shape, one side (bottom) of which is blind, and the other has a special flange for mounting on the tank flange. The latter is located on one of the bottoms of the container.
The difference between both schemes is obvious:
- In the first version, both the air and water volumes are located in the inner cavity of the tank, only divided in the middle by a membrane;
- In the second version, the water volume is inside the pear, and the air volume is between it and the inner walls of the tank.
In any case, on one of the ends of the accumulator there is a flange with a valve for supplying / removing water, and on the other - for air. The pressure in the tank and the system is set by changing the volumes of the two cavities. This can be clearly seen in the example of the last illustration, therefore, the principle of operation of such an installation can also be formulated:
- At the initial stage, when the pump does not work, when there is no draw-off, and the pressure in the system is established, the water cavity remains empty, respectively, the air cavity has a maximum volume;
- When the pump is turned on, water begins to flow into the tank and displace air. The latter presses on the valve disc, blocking it;
- Since water, in terms of its physical and mechanical characteristics, is a practically incompressible medium, the volume of the air cavity decreases. Accordingly, at the same time, the pressure in it increases, which is controlled by the corresponding relay. As soon as the threshold is reached, it disconnects the pump from the network;
- At the beginning of the water draw, for example, when the consumer opens the tap, water from the tank under pressure goes into the supply line, thereby allowing the pump to remain off.
As it is not difficult to guess, the relay will give voltage to the pump contacts at the moment when the pressure in the tank reaches the lower threshold mark and the cycle described above will be repeated again.
Important! Despite the statements of many "knowledgeable" consultants in stores, the statement that the accumulator maintains constant pressure in the system is fundamentally wrong. Firstly, because its only working body is a rubber membrane, which does not have a drive, which means that it is not able to independently change its shape and influence the pressure inside the tank. This process occurs due to the inflow / outflow of water that is pumped by the pump! Secondly, the role of the GA boils down to ensuring a smooth change in pressure in the system, excluding its sharp increase or decrease when closing or opening the taps, and therefore, leveling the risk of water hammer.
Another, possibly basic, principle of the classification of accumulators is the installation method: vertical and horizontal. Their principle of operation is the same, but the main difference lies in the scheme for removing air that accumulates in the system. In vertical-type tanks, a special valve is located in the upper part, and in a horizontal layout, a special section of the pipeline is equipped outside the tank. Similar solutions are used with tank volumes above 50-100 liters, and on small-sized accumulators, regardless of the scheme, air is bleed off by completely draining the water.
Volume selection
Obviously, in order to ensure optimal operating conditions for the water supply system, the accumulator is primarily selected based on the required volume. In this case, you can use both general (approximate) recommendations, and adopt quite specific calculation methods. In the first case, the final choice may be influenced by the purpose for which the container is supposed to be used. As practice shows, there are plenty of options here.
Minimizing the number of pump starts
From the point of view of saving energy and extending the service life, the pump should be turned on no more than 30 times per hour. For an approximate calculation of the volume in this case, you will have to take into account two more parameters:
- Pump capacity (QH). In most household appliances, it is approximately 2-3 m3 / h (2000-3000 l / h);
- The useful volume of the accumulator (VEF). This is the amount of water that can be withdrawn from the tank within the minimum and maximum pressure of the relay (respectively, turning on and off the pump). In practice, it is about 40% of the total capacity.
To ensure this condition, you need to choose a tank with a total volume of at least:
V_min = Q_H / (30 ∙ V_EF) = (2000… 3000) / (30 ∙ 0.4) = 170… 250 l
Most manufacturers draw up special tables based on pump on / off pressures and air pre-pressures.
Reserve water source
There are plenty of cases when electricity goes out, which means that the pump does not work. In such a situation, the useful volume of water in the accumulator can be used as a reserve without the need to withdraw it from the system. Obviously, the minimum value should be determined according to the previous method, and the optimal one - taking into account the number of consumers and the approximate water consumption.
So, in most cases, for a family of 1-2 people, a tank with a capacity of 24 liters is enough, with three consumers - from 50 liters, and with four or more - from 100 liters. The first thing that comes to mind in this situation is that the more volume, the better. But, one should not forget that water reserve is more of a side effect or a bonus than a main function. The main thing here is not to overdo it, so that unpleasant consequences do not arise (more on this later), but it is better to use special containers, which are intended for this.
Minimum volume of GA
For theoretical calculations, you can use the following relationship:
V_min = (K ∙ A_max ∙ (P_max + 1) ∙ (P_min + 1)) / ((P_max-P_min) ∙ (P_AIR + 1))
In this formula: K is the power factor of the engine; Аmax - maximum pump flow rate, l / min; Рmin, Рmax - pressure on and off the pump, bar; Rozd - air pressure in the HA chamber, bar. All of these parameters are listed in the device specification sheet.
A hydraulic accumulator is a special metal sealed container containing an elastic membrane inside and a certain volume of water under a certain pressure.
A hydraulic accumulator (in other words, a membrane tank, a hydraulic tank) is used to maintain a stable pressure in the water supply system, protects the water pump from premature wear due to frequent switching on, and protects the water supply system from possible water hammer. When the power is turned off, thanks to the accumulator, you will always be with a small supply of water.
Here are the main functions that a hydraulic accumulator performs in a water supply system:
- Protection of the pump from premature wear. Due to the water supply in the membrane tank, when the water tap is opened, the pump will turn on only if the water supply in the tank runs out. Any pump has a certain rate of inclusions per hour, therefore, thanks to the hydraulic accumulator, the pump will have a supply of unused inclusions, which will increase its service life.
- Maintaining constant pressure in the water supply system, protection against water pressure drops. Due to pressure drops, when several taps are turned on at the same time, sharp fluctuations in water temperature occur, for example, in the shower and in the kitchen. The accumulator copes with such unpleasant situations successfully.
- Protection against water hammer, which can occur when the pump is turned on, and can spoil the pipeline in order.
- Maintaining a supply of water in the system, which allows you to use water even during a power outage, which happens quite often nowadays. This function is especially valuable in country houses.
Accumulator device
The sealed body of this device is divided by a special membrane into two chambers, one of which is designed for water, and the other for air.
The water does not come into contact with the metal surfaces of the case, as it is in a water chamber-membrane made of strong butyl rubber material, resistant to bacteria and complying with all hygienic and sanitary standards for drinking water.
There is a pneumatic valve in the air chamber, the purpose of which is to regulate the pressure. Water enters the accumulator through a special threaded connection pipe.
The accumulator device must be mounted in such a way that it can be easily disassembled in the event of repair or maintenance, without draining all the water from the system.
The diameters of the connecting pipeline and the discharge branch pipe should, if possible, coincide with each other, then this will avoid unwanted hydraulic losses in the system pipeline.
In the membranes of accumulators with a volume of more than 100 liters, there is a special valve for bleeding the air released from the water. For small-capacity accumulators in which there is no such valve, a device for bleeding air should be provided in the water supply system, for example, a tee or a tap that blocks the main line of the water supply system.
In the air valve of the accumulator, the pressure should be 1.5-2 atm.
The principle of operation of the accumulator
The accumulator works like this. The pump supplies water under pressure to the accumulator diaphragm. When the pressure threshold is reached, the relay turns off the pump and water stops flowing. After the pressure begins to drop during water intake, the pump automatically turns on again and supplies water to the accumulator membrane. The larger the volume of the hydraulic tank, the more efficient the result of its work. The actuation of the pressure switch can be adjusted.
During the operation of the accumulator, air dissolved in water gradually accumulates in the membrane, which leads to a decrease in the efficiency of the device. Therefore, it is necessary to carry out preventive maintenance of the accumulator, bleeding the accumulated air. The frequency of prophylaxis depends on the volume of the hydraulic tank and the frequency of its operation, which is approximately once every 1-3 months.
These devices can be in vertical or horizontal configuration.
The principle of operation of the devices does not differ, except that vertical accumulators with a volume of more than 50 liters in the upper part have a special valve for bleeding air, which gradually accumulates in the water supply system during operation. Air accumulates in the upper part of the device, therefore, the location of the bleed valve is chosen precisely in the upper part.
In horizontal devices for bleeding air, a special tap or drain is mounted, which is installed behind the accumulator.
From devices of small sizes, regardless of whether they are vertical or horizontal, air is vented by completely draining the water.
Choosing the shape of the hydraulic tank, proceed from the dimensions of the technical room where they will be installed. It all depends on the dimensions of the device: which one fits better into the space allotted for it, this will be installed, regardless of whether it is horizontal or vertical.
Accumulator connection diagram
Depending on the assigned functions, the connection diagram of the accumulator to the water supply system may be different. The most popular schemes for connecting hydraulic accumulators are shown below.
Such pumping stations are installed where there is a large water consumption. As a rule, one of the pumps at such stations runs constantly.
At the booster pumping station, the accumulator serves to reduce pressure surges during the activation of additional pumps and to compensate for small water drawdowns.
Such a scheme is also widely used when there is a frequent interruption in the supply of electricity to the booster pumps in the water supply system, and the presence of water is vital. Then the water supply in the accumulator saves the situation, playing the role of a reserve source for this period.
The larger and more powerful the pumping station, and the more pressure it must maintain, the larger the volume of the hydraulic accumulator, which plays the role of a damper, must be.
The buffer capacity of the hydraulic tank also depends on the volume of the required supply of water, and on the difference in pressure when the pump is turned on and off.
For long-term and trouble-free operation, a submersible pump must perform from 5 to 20 starts per hour, which is indicated in its technical characteristics.
When the pressure in the water supply system drops to the minimum value, the pressure switch automatically turns on, and at the maximum value it turns off. Even the smallest water consumption, especially in small water supply systems, can reduce the pressure to a minimum, which will instantly give a command to turn on the pump, because the water leak is compensated by the pump instantly, and after a few seconds, when the water supply is replenished, the relay will turn off the pump. Thus, with minimal water consumption, the pump will run almost idle. This mode of operation adversely affects the operation of the pump and can quickly damage it. The situation can be corrected by a hydraulic accumulator, which always has the necessary supply of water and successfully compensates for its insignificant consumption, and also protects the pump from frequent switching on.
In addition, the accumulator connected to the circuit smooths out a sharp increase in pressure in the system when the submersible pump is turned on.
The volume of the hydraulic tank is selected depending on the frequency of switching on and the power of the pump, the water consumption per hour and the height of its installation.
For a storage water heater, in the connection diagram, the hydraulic accumulator plays the role of an expansion tank. As the water heats up, it expands, increasing the volume in the water supply system, and since it does not have the property of contracting, the very minimum increase in volume in a confined space increases pressure and can lead to the destruction of the elements of the water heater. Here, too, a hydraulic tank will come to the rescue. Its volume will directly depend and increase from an increase in the volume of water in the water heater, an increase in the temperature of the heated water and an increase in the maximum allowable pressure in the water supply system.
The hydraulic accumulator is connected in front of the booster pump along the water flow. It is needed to protect against a sharp drop in pressure in the water supply network at the moment the pump is turned on.
The capacity of the accumulator for the pumping station will be the greater, the more water is used in the water supply system and the smaller the difference between the upper and lower pressure scales in the water supply in front of the pump.
How to install a hydraulic accumulator?
From the foregoing, it can be understood that the device of the hydroaccumulator is absolutely not like an ordinary water tank. This device is constantly in operation, the membrane is in dynamics all the time. Therefore, the installation of the accumulator is not so easy. The tank must be strengthened during installation reliably, with a margin of safety, noise and vibration. Therefore, the tank is fixed to the floor through rubber gaskets, and to the pipeline through flexible rubber adapters. You need to know that at the inlet of the hydraulic system, the cross-section of the supply line should not narrow. And one more important detail: the first time you need to fill the tank very carefully and slowly, using a weak pressure of water, in case the rubber bulb has stuck together from a long inactivity, and with a sharp pressure of water, it can be damaged. It is best to remove all air from the pear before commissioning.
The installation of the accumulator should be carried out so that during operation it was possible to freely approach it. It is better to entrust this task to experienced specialists, since very often the tank breaks down due to some unaccounted, but important trifle, for example, due to a discrepancy in the diameter of the pipes, unregulated pressure, etc. Experiments cannot be carried out here, because the normal operation of the water supply system is at stake.
Here you have brought the purchased hydraulic tank into the house. What to do with it next? It is immediately necessary to find out the level of pressure inside the tank. Usually, the manufacturer pumps it up to 1.5 atm, but there are cases when, due to a leak, by the time of sale, the indicators decrease. To make sure that the indicator is correct, you need to unscrew the decorative cap on an ordinary automobile spool and check the pressure.
How can you check it? Usually a pressure gauge is used for this. It can be electronic, mechanical automotive (with a metal case) and plastic, which is supplied with some pump models. It is important that the pressure gauge has greater accuracy, since even 0.5 atm changes the quality of the hydraulic tank, so it is better not to use plastic pressure gauges, as they give a very large error in the readings. These are usually Chinese models in a weak plastic case. Electronic pressure gauges are affected by battery charge and temperature, and they are very expensive. Therefore, the best option is an ordinary car pressure gauge that has been tested. The scale should be in a small number of divisions in order to be able to measure the pressure more accurately. If the scale is designed for 20 atm, but you need to measure only 1-2 atm, then you should not expect high accuracy.
If there is less air in the tank, then there is a greater supply of water, but the difference in pressure between an empty and almost full tank will be very significant. It's all about preference. If it is necessary that a high pressure of water is constantly in the water supply system, then the pressure in the tank must be at least 1.5 atm. And for domestic needs, 1 atm may well be enough.
At a pressure of 1.5 atm, the hydraulic tank has a smaller water supply, because of which the pumping pump will turn on more often, and in the absence of light, the water supply in the tank may simply not be enough. In the second case, you will have to sacrifice pressure, because you can take a shower with a massage when the tank is full, and as it becomes empty, only a bath.
When you decide what is more important to you, you can set the desired operating mode, that is, either pump air into the tank, or bleed off excess air.
It is undesirable to reduce the pressure below the 1 atm mark, as well as excessively exceed it. A pear filled with water with insufficient pressure will touch the walls of the tank, and can quickly become unusable. And excessive pressure will not allow pumping a sufficient volume of water, since most of the tank will be occupied by air.
Pressure switch setting
You also need to adjust the pressure switch. Opening the lid, you will see two nuts and two springs: large (P) and small (delta P). With their help, you can set the maximum and minimum pressure levels at which the pump turns on and off. A large spring is responsible for turning on the pump and pressure. By design, you can see that it kind of helps the water to close the contacts.
With the help of a small spring, the pressure difference is set, which is specified in all instructions. But the instructions do not indicate a starting point. It turns out that the point of reference is the spring nut P, that is, the lower limit. The lower spring, which is responsible for the pressure difference, resists the water pressure and pushes the movable plate away from the contacts.
When the correct air pressure has already been set, you can connect the accumulator to the system. Having connected it, you need to carefully observe the pressure gauge. On all accumulators, the values of normal and maximum pressures are indicated, the excess of which is unacceptable. Manual disconnection of the pump from the network occurs when the normal pressure of the accumulator is reached, when the limit value of the pump head is reached. This occurs when the pressure rise stops.
The power of the pump is usually not enough to pump the tank to the limit, but there is even no special need for this, because when pumping, the service life of both the pump and the pear is reduced. Most often, the pressure limit for shutdown is set 1 to 2 atm higher than that for switching on.
For example, when the pressure gauge reads 3 atm, which is enough for the needs of the owner of the pumping station, you need to turn off the pump and slowly rotate the nut of the small spring (delta P) to decrease, until the mechanism is triggered. After that, you need to open the tap and drain the water from the system. Observing the pressure gauge, it is necessary to note the value at which the relay turns on - this is the lower pressure limit when the pump turns on. This indicator should be slightly more than the pressure indicator in an empty accumulator (by 0.1-0.3 atm). This will make it possible for the pear to last for a longer period of time.
When the nut of the large spring P rotates, the lower limit is set. To do this, turn on the pump to the network and wait until the pressure reaches the desired level. After that, it is necessary to adjust the nut of the small spring "delta P" and complete the adjustment of the accumulator.
In the air chamber of the accumulator, the pressure should be 10% lower than the pressure when the pump is turned on.
The exact indicator of air pressure can be measured only when the tank is disconnected from the water supply system, in the absence of water pressure. The air pressure must be constantly monitored and adjusted as necessary, which will add a lifetime to the membrane. Also, to continue the normal functioning of the diaphragm, a large pressure drop must not be allowed when the pump is turned on and off. A drop of 1.0-1.5 atm is normal. Stronger pressure drops reduce the life of the membrane, stretching it strongly, moreover, such pressure drops do not make it possible to use water comfortably.
Hydraulic accumulators can be installed in places with low humidity, not susceptible to flooding, so that the flange of the device will successfully serve for many years.
When choosing a brand of accumulator, it is necessary to pay special attention to the quality of the material from which the membrane is made, to check the certificates and sanitary and hygienic conclusions, making sure that the hydraulic tank is designed for systems with drinking water. You also need to make sure that you have spare flanges and diaphragms, which should be included, so that in case of a problem you do not have to buy a new hydraulic tank.
The maximum pressure of the accumulator for which it is designed should be no less than the maximum pressure in the water supply system. Therefore, most devices can withstand a pressure of 10 atm.
To determine how much water can be used from the accumulator when the electricity is turned off, when the pump stops pumping water from the water supply system, you can use the diaphragm tank filling table. The water supply will depend on the setting of the pressure switch. The higher the pressure difference when the pump is turned on and off, the more water will be in the accumulator. But this difference is limited for the reasons stated above. Consider a table.
Here we see that in a 200-liter membrane tank with the pressure switch settings, when the pump is turned on is 1.5 bar, the pump is turned off - 3.0 bar, the air pressure is 1.3 bar, the water supply will be only 69 liters, which is about a third of the total tank volume ...
Calculation of the required volume of the accumulator
To calculate the accumulator, use the following formula:
Vt = K * A max * ((Pmax + 1) * (Pmin +1)) / (Pmax- Pmin) * (Pair + 1),
- Amax - maximum flow rate of liters of water per minute;
- K is a coefficient that depends on the power of the pump motor;
- Pmax - pressure when the pump is turned off, bar;
- Pmin - pressure when the pump is turned on, bar;
- Air - air pressure in the accumulator, bar.
As an example, we will select the required minimum volume of a hydraulic accumulator for the water supply system, taking, for example, a pump Aquarius BTsPE 0.5-40 U with the following parameters:
| Pmax (bar) | Pmin (bar) | Air (bar) | A max (cubic meters / hour) | K (coefficient) |
| 3.0 | 1.8 | 1.6 | 2.1 | 0.25 |
Using the formula, we calculate the minimum volume of GA, which is 31.41 liters.
Therefore, we choose the next closest GA size, which is 35 liters.
The volume of the tank in the range of 25-50 liters is ideally consistent with all methods for calculating the volume of HA for domestic water supply systems, as well as with the empirical purposes of different manufacturers of pumping equipment.
With frequent power outages, it is advisable to choose a larger tank, but at the same time it should be remembered that water can only fill the tank by 1/3 of the total volume. The more powerful the pump is installed in the system, the larger the volume of the accumulator should be. This dimensional alignment will reduce the number of pump strokes and extend the life of the pump motor.
If you bought a large-volume hydroaccumulator, you need to know that if water is not used regularly, it stagnates in the GA tank and its quality deteriorates. Therefore, when choosing a hydraulic tank in a store, you need to take into account the maximum volume of water used in the water supply system at home. Indeed, with a low water consumption, it is much more expedient to use a tank with a volume of 25-50 liters than 100-200 liters, the water in which will be wasted.
Repair and maintenance of a hydraulic accumulator
Even the simplest hydraulic tanks require attention and care, like any working and useful device.
There are different reasons for repairing a hydraulic accumulator. These are corrosion, dents in the body, violation of the integrity of the membrane or a violation of the tightness of the tank. There are also many other reasons that oblige the owner to repair the hydraulic tank. In order to prevent serious damage, it is necessary to regularly inspect the surface of the accumulator, monitor its operation in order to prevent possible problems. It is not enough to inspect the GA twice a year, as stipulated in the instructions. After all, you can eliminate one malfunction today, and tomorrow you will not pay attention to another problem that has arisen, which within six months will turn into irreparable and can lead to the failure of the hydraulic tank. Therefore, the accumulator must be inspected at every opportunity so as not to miss the slightest malfunctions, and to carry out their repairs on time.
Causes of breakdowns and their elimination
The reason for the breakdown of the expansion tank may be too frequent switching on and off of the pump, water outlet through the valve, weak water pressure, weak air pressure (below the calculated one), weak water pressure after the pump.
How to fix a hydroaccumulator malfunction with your own hands? The reason for the repair of the accumulator can be a weak air pressure or its absence in the membrane tank, damage to the membrane, damage to the casing, a large difference in pressure when turning the pump on and off, incorrectly selected volume of the hydraulic tank.
You can troubleshoot as follows:
- to increase the air pressure, it is necessary to pump it through the tank nipple with a garage pump or compressor;
- a damaged membrane can be restored at a service center;
- the damaged case and its tightness is also eliminated in the service center;
- you can correct the difference in pressure by setting a differential too large in accordance with the frequency of pump starts;
- the sufficiency of the tank volume must be determined before installing it in the system.
For city dwellers, a hydraulic accumulator for water supply systems (water accumulator or hydraulic tank) is a completely unfamiliar concept. Having bought, for example, a summer cottage or a country house in an area without a central water supply, the owners are stunned by the multitude of complex abbreviations, technical requirements, and concepts. Such as: an autonomous water supply system, a submersible pump with a frequency converter, setting the minimum and maximum pressure, the maximum number of starts of the submersible pump. And all this just so that water flows from the tap in the house. In this article, we will discuss the role of this device in pump-type systems.
The most common type of hydraulic tank
Note! Not to be confused with an expansion tank for a heating system, the two devices are similar in shape and design. For the most part, the expansion tank is red, and the accumulator is blue, but not always. Check with the sales manager when purchasing what function the device you need should perform.
This structural element has two main purposes:
- Ensuring uninterrupted and uniform operation of the pumping station;
- Ensuring the reliability and integrity of the DHW system (hot water supply).
The role of the accumulator in the pumping station
In the absence of a central water supply, the owners of private houses, to supply water to the house, drill a well or erect a well equipped with a deep pump. With its help, water is supplied to the room, fills the water accumulator, is necessarily filtered and branched out to the places of consumption.
Let's take a closer look at the operation of this scheme. When you quickly open and close the water tap, for example, you rinsed your hands, a small amount of water is consumed and it is at this moment that the accumulator begins to work. The pump did not turn on, the pressure was created by the pressure of the membrane of the water accumulator, since it contains a certain amount of water. Numerous sources claim that an emergency water supply is the main function that a hydraulic accumulator performs for water supply systems. This information is incorrect. The unit with a capacity of 100 liters can hold no more than 35 liters of water.
The primary purpose of installing this unit is to save an expensive submersible pump from overheating and irrational starts. In the absence of this device, the pump, in the case described above, will start and turn off immediately, without gaining maximum power. At this moment, a water hammer is created in the circuit, that is, a sharp pressure drop. The unit with the combination of these factors will quickly fail. Conclusion - a hydraulic accumulator in water supply systems serves to evenly distribute the pressure in the circuit and long-term operation of pumping equipment.
Accumulator in the DHW system
There are three main types of hot water supply using a hydraulic tank:
- Installation of an indirect heating boiler;
- Installation of a double-circuit solid fuel boiler, with the function of supplying hot water;
- Scheme with a single-circuit boiler in conjunction with an indirect heating boiler.
In any of the options, the water accumulator plays the role of an expansion tank, since water increases in volume when heated, and this device compensates for the amount of water. Despite the fact that both in the boiler and in the solid fuel boiler there is a safety group in the form of a bypass valve, with constant operation, the bypass valve quickly fails, this entails damage to the boiler or a leak in the water supply circuit.
Note! The appearance and shape of a hydro accumulator tank for cold water supply is very similar to a hydroaccumulator for hot water supply. Their difference is in the temperature resistance of the built-in membrane. When purchasing, carefully read the technical specifications of the device. Inexperienced managers often offer a sample that you do not need.
Accumulator classifications
A hydraulic accumulator, as a concept, has many areas of application. It is used in all types of mechanical engineering, in heavy industry. In this article, we will look at hydraulic tanks used only in the domestic water supply. The most popular in this industry are pneumatic units. They are divided into two types:
- Membrane disposable. Samples in which the membrane is enclosed in a retaining ring in the center of the tank;
- Water accumulators with the possibility of membrane replacement.
Each of these types has a different form of execution:
- Vertical;
- Horizontal.
Related article:
In the article, we will look at how to solve the problem of insufficient water pressure, which complicates the adoption of water procedures and the operation of auxiliary household appliances, how to choose the right pump, and what to look for.
Principles of operation, design and advantages of a hydraulic tank in water supply systems
What does the hydraulic tank consist of?
- The body of the device is most often made of ordinary steel. There are stainless steel samples. They are more durable, but less common due to their high cost;
- Rubber membrane. It is made of elastic material, which ensures long-term operation;
- The working pressure is controlled through a spool, using a conventional machine pump and a pressure gauge;
- A coarse filter is installed in the housing, in addition to a separate filter built into the circuit.
The group of battery equipment also includes a pressure switch - this is an automatic sensor for starting and stopping the pumping unit.
The advantages of pneumatic equipment are:
- Simplicity of construction;
- The possibility of replacing the membrane;
- Simple connection to a pumping station;
- Compact dimensions;
- Light weight;
- Affordable price
Let's briefly describe the operation of the water accumulator
When water is consumed at any point of the water intake, the pressure switch turns on the pump unit. Water entering the hydraulic tank stretches the membrane. Further, when the tap is closed, the pump continues to work. The diaphragm expands to increase the operating pressure of the unit. When the pressure rises to the maximum value, the pressure switch turns off the pumping unit.
When planning a water supply system, all the constituent elements are interconnected. Before buying any device, be it a pumping station, a hydraulic accumulator, water pipes, filters and so on, consult with a specialist or carefully study all the necessary information in order to avoid waste of money.
You should start planning water supply by calculating the water consumption of your home, how many points of water intake are planned. For example: two bathrooms, two showers, washing machine, dishwasher, kitchen faucet, watering faucet. How many people live in your house, that is, the simultaneous operation of water at different points.
There can be a great variety of variations. These points are very important, since when buying a deep-well pump of insufficient power, there is not enough water for everyone, you cannot wash off the soap from yourself in the shower until the washing machine finishes working. In the case when your house has a standard number of taps: one bathroom, one kitchen faucet, a washing machine, one shower cabin and there are 4 people in your family, a device with a volume of 25-50 liters will suit you. Such specimens are almost always ideally suited to any pump of the corresponding power.
In the case of a larger number of people and water consumption points, a rational calculation is carried out according to the formula:
With a standard scheme, where water comes, for example, from a well or a shallow well, the power of a conventional pump is quite enough to supply water even to the second or third floor. In this case, the system does not cause any difficulties and the hydraulic device is installed indoors.
What is required to assemble the entire hydroaccumulator group
The hydraulic tank group, in addition to the pressure switch, includes a pressure gauge.
For the convenience of connecting all components, a five-way fitting is used.
When assembling the entire group, it is recommended to use American cranes. For the smooth removal and replacement of any device in the event of a breakdown. That is, to the outlet to the accumulator, to the pipe leading to the pump and to the wiring to consumers. If you gather a group without "American women", with a minor breakdown or replacement of the membrane, for example, you will have to drain the water from the entire system.
When installing the system, there are many pitfalls and working little things. We will try to describe the main ones:
- How to detect a broken water battery;
- Energy saving method;
- Insurance in case of inattention when the pump is on;
- Tips for replacing the membrane;
- Increasing the volume of a hydraulic device when installing a solid fuel boiler;
- A recommendation for the purchase of hydraulic equipment with a volume of more than 100 liters.
A brief explanation for each item.
It is an integral part of modern automatic water supply systems for a private house, cottage or summer cottage. There are many types and configurations of cold water expansion tanks on the market.
Today we will analyze in detail the device and the principle of operation of the accumulator, its main purpose, installation rules and possible malfunctions. We will also try to understand the principle of operation, and how to choose the right accumulator for our pumping system.
Main types and features
Hydraulic accumulators for water supply systems differ in layout:
- horizontal
- vertical
By volume or capacity:
- standard household: 24-50 liters
- medium capacity: 80-100 liters
- large capacity: 150 liters and more
By the material of manufacture of the case:
- steel enameled
- made of stainless steel
Horizontal hydraulic accumulator for pumping station
The body of the steel accumulator is usually painted with blue or green enamel. Expansion tanks of red color are more often intended for heating systems.
Application area
Hydraulic accumulators are designed for:
- accumulation of water and maintaining its automatic supply to the point of water intake
- increasing the service life of the pump, removing the load on it when it is turned on frequently
- prevention of possible water hammer in the water supply system
The device and principle of operation of the accumulator
A typical hydraulic accumulator consists of the following elements (see diagram below):
1 - threaded nipple for connection to the water supply system, its diameter is usually 25 mm or 1 inch
2 - flanges for sealing
3 - the containers of different volumes
4 - rubber membrane for water
5 - pneumatic valve for pumping and venting air
6 - mounting platform for installing a surface pump on it
(for horizontal design)
7 - legs for structural stability
Hydraulic tank device
The principle of operation of the accumulator is based on the automatic supply of water from the tank to the consumer without turning on the pump. This is due to the fact that when the water tap is opened, the air pumped into the container begins to squeeze water out of the membrane under pressure.
The required pressure in the tank should be 1.5-2 atmospheres. As the consumer consumes water, after closing the tap, the hydroaccumulator automatically refills with water throughout its entire volume.
How to choose a hydraulic accumulator for a pump
If you plan to buy and do not know with what volume of the tank to choose it, or you already have a surface pump, but plan to purchase a hydraulic accumulator for it, then the following is recommended:
- for a pump with a power of up to 1000 W, a tank with a capacity of 24 liters is suitable
- for a pump with a capacity of more than 1000 W it is better to buy a tank with a volume of 50 liters
If you purchase a hydraulic accumulator for, then it is recommended for pumps with a capacity of:
- up to 500 W install a tank with a volume of 24 liters
- up to 1000 W, 50 liters are suitable
- up to 1500 W - 80 or 100 liters
Due to the nature of their design, submersible pumps turn on and off less frequently than surface pumps. Therefore, it is necessary for them to install somewhat large accumulators in volume.
In practice, expansion tanks with a volume of 24-50 liters are able to fully meet the need for household water for a small family, for one or two points of water intake. If the family is large, you can buy a larger hydraulic tank. For example, a tank with a volume of 80-100 liters should be enough for three to four points of water intake: a kitchen, a bathroom, a shower and a toilet.
Vertical type hydroaccumulators
Hydraulic Tank Installation Recommendations
1. Install the accumulator only in a heated room.
2. Before starting, remember to flush the water supply first.
3. Check if the air has been pumped into the tank with sufficient pressure.
If not, then pump up to 2 atm. independently through the pneumatic air valve. This procedure can be done, for example, with a conventional bicycle or car pump.
Problems at work and methods of their elimination
1. Insufficient air pressure.
Purge pneumatic valve and pump air in.
2. Lack of air under pressure in the accumulator tank.
Either the valve or the diaphragm will need to be replaced.
3. Water flows from the valve.
Replacement of the membrane is required. Watching the video.
Hydraulic accumulator for water supply systems- this is an indispensable attribute of a modern suburban private house or summer cottage. I hope you now understand its principle of operation and design features. And now you can easily choose a hydraulic accumulator for your conditions, as well as install it correctly, and prevent mistakes when starting the water supply system.