Pressure capacity. What are pressure tanks for? Bottom connection of storage tank with membrane

18.10.2019

Today we have to study the control tanks in the water supply system. We will find out what they can be and what functions they perform. In addition, we will get acquainted with a number of popular water supply schemes with various types of containers.

First meeting

Our list includes:

Image	Description
	Accumulative non-pressure tanks. Them characteristics- large internal volume and no overpressure. Water is supplied to the consumer by gravity or by a pump.
	Heat accumulators and boilers. Their function is to create a reserve hot water to ensure its peak consumption. The volume of the tank varies from 10 to 3000 liters; this class of devices can heat water on its own or use an external heat source.
Attention: pumping station can lift water from a depth of no more than 8-9 meters. The limitation is related to physical constants: the maximum theoretically possible pressure drop at the ends of the suction pipe of 1 atmosphere for a surface pump is capable of raising the water column by only 10.3 meters. What are the advantages of a pumping station over a submersible pump? In simple maintenance. Lifting a well pump is a rather complicated operation, which can be prevented by deformation of the wellbore or a broken cable; In mobility. The surface pump can be taken away from the dacha for the winter; In cheapness. A pumping station with comparable performance will cost 2-3 times cheaper than a set of a borehole pump with a hydraulic accumulator. Water hammer absorber The water hammer damper can be mounted: At the water supply inlet with a series connection of water points; Directly in front of the plumbing fixture. In this case, it protects the device itself and its flexible connections from a pressure surge; On the collector of the radial distribution of water supply. Conclusion As you can see, under a common name, the most different types plumbing fittings. To learn more about where and how control tanks are used for water supply, the video in this article will help you. Good luck!

In modern heating systems and water supply systems, special membrane-type expansion water tanks are installed as protection equipment. Often such membrane tanks are called pressure tanks, and sometimes even "hydropneumatic tanks" and "hydraulic accumulators". In the water supply system, they are designed to perform three important functions.

The main function of membrane tanks is obvious - this is a reservation, or accumulation water resource, as well as maintaining water pressure in the pipes. The pressure tank in this case is a reserve tank that accumulates water reserves. When the tap is turned on and the water intake begins, the pressure of the water entering the system comes from such a tank. When the water reserves in the "hydraulic accumulator" decrease and the pressure level inside the pipes drops below the permissible limit, the pump starts. Further, if the tap is turned off, the pump does not stop working, but continues to pump water into the membrane tank. Over time, the tank is completely filled, the upper pressure limit in it is reached, and the automation turns off the pump. It is logical that the use of a membrane tank increases the life of not only the pump, but the entire system as a whole. And all because in its absence and a high frequency of turning on / off the taps of the water system, the pump would have to constantly switch from one state to another.

The second important function of the tanks is to prevent water hammer. Water hammer is such a pressure jump in the system when the energy of movement of a sharply stopped water flow in the pipeline is converted into energy that destroys the walls of the pipeline. The risk of water hammer is high when the valve suddenly closes. Such a blow is no less likely during the shutdown of various household electrical appliances, such as, for example, washing machine. "Hydroaccumulator". In this case, it does not allow a sharp change in pressure and plays the role of a silencer for such shocks.

Well, the third function is, of course, the creation of a supply of water in case of an accident: be it a temporary shutdown of a pumping station, or something like that. With a membrane tank in the house there will always be a spare vessel with water.

It is necessary to distinguish between membrane tanks for water supply and heating systems, although outwardly they are very similar to each other. In most cases, they look like spherical metal vessels. Unlike a pressure tank, the main function of a membrane tank for a heating system is to reserve excess water resulting from its thermal expansion for subsequent return to the system. Like pressure tanks, they act as a dampener for hydraulic shocks in the system. Both types of tanks have a special elastic membrane inside, made of heat-resistant rubber. This membrane divides the vessel into two parts (for air and for liquid) and is able to stretch, which allows the system to be in equilibrium with pressure drops. Our

One of the most annoying domestic problems is the lack of water in the tap. It is easy to survive the absence of light or gas, but water is an indispensable component of human life, and when it is not there or not enough, problems begin. You can constantly keep several containers of water in the house, for example, plastic bottles, but it is much more practical to determine what kind of storage tank for water supply and the system diagram for a private house are needed so as not to lose comfort and continue to use household appliances and a sink with a bathroom, no matter how what never happened.

Why is it needed and how to use it

If for some reason the pump in the autonomous water supply system does not work, or there is no pressure in the centralized city water supply, then it can be supplied to the sink or toilet bowl from a previously collected reserve tank. In other words, it is better to always have a supply in the house. drinking water and use it in emergency situations.

For the convenience of using the reserve water supply, the storage tank must be integrated into the water supply system so that it is either automatically used in the absence of external pressure, or it can be activated by simply turning the valve.

There are many variations on how to install and connect a storage tank, depending on the type of water source, the possible location of the tank, and even the layout of the house. Enough to choose suitable option and decide on the type of storage tank itself.

Types

The storage tank can be a tank with a sufficient internal volume, made of a material resistant to corrosion and safe for storing drinking water. The following materials are used:

polyvinyl chloride;
cross-linked polyethylene of high or low pressure;
polypropylene;
stainless steel;
steel coated with waterproof varnishes and ceramic coatings.

plastic tanks

Although galvanized steel is resistant to corrosion and waterproof, over time the protective layer of zinc can become thinner, especially at the joints and welds.

By design, allocate:

open containers that have a neck with or without a lid, but with sealed walls and a bottom;
closed fully sealed containers of membrane type.

In the first case, everything is simple, the entire internal volume is filled with water and, if necessary, drains through a pipe fixed at the lowest point.

In the case of membrane storage tanks, the usable volume is at least a third less than the volume of the entire structure. Part of the volume is allocated under the air chamber, separated from the water by a strong elastic membrane. As the container fills with water, the membrane presses on the air chamber, creating excess pressure. When it is required to receive water back, the valve opens, and it enters the water supply system under the action of the accumulated pressure.

Bottom or top

There are three connection options storage capacity and use of the water supply:

Top location of the container. In this case, the water intake is carried out under the action of gravity. The higher the accumulator is located in relation to the consumer, the stronger the water pressure. Every 10 meters of altitude adds 0.1 atmosphere, or about 1 bar.
The lower location of a simple storage tank. Gravity will no longer help, and a pump is used to supply the water supply, raising the pressure to the optimum level.
Membrane-type storage tanks themselves create the required pressure for water supply. The lower location at the level of the consumer is optimal for them, since there will be no advantage from installation in an attic or tower.

How to determine the best option?

If a house with several floors and it is possible to place a storage tank in the attic, then this will allow you to do without additional installation pump, and no need to spend money on an expensive membrane tank. In fact, this is an analogue of a water tower. However, raise the container so high as to provide a comfortable pressure at the level of 2-2.5 atm. it's still difficult. Moreover, the question arises of insulating the tank, so that in winter period the water did not freeze.

In the event of an emergency shutdown of the available water pressure of 0.2-0.3 atm. will be quite enough to use the faucet in the sink, toilet or even shower, but it will not be possible to use part household appliances such as a washing machine or dishwasher that requires more pressure to operate the solenoid valves.

Installing the tank at the level with the consumer is suitable in cases where it is not possible to raise the tank to the attic or at least one floor higher. The same applies to the installation of a storage tank in the apartment. You will need a small pump to supply water to the water supply under pressure. To ensure adequate operation, the pump will require an expansion membrane tank.

A storage tank with a membrane is perfect for storing water both when using a centralized water supply system and in an autonomous system. However, it does not require additional equipment or top location. However, its cost is much higher than any conventional storage tank, even when combined with a simple pump.

Volume of the tank

In the event of problems on the city water line and water cuts, it is usually repair work done in a day or two. However, accidents also happen on holidays, and in places where a quick repair is simply impossible, then you have to wait much longer. The optimal supply of water for 2-3 days is based on the use of the toilet, maintaining personal hygiene and cooking.

For a family of three, 100 liters per day is enough when using water in economy mode. For one wash, approximately 80 liters of water are required, you can find out more precisely in the passport for the washing machine. Same for dishwasher.

It turns out that for 2-3 days when using household appliances, you need to look for a storage capacity of at least 500 liters, half a cubic meter.

However, there are a number of limitations:

The larger the volume of water and the storage tank of an open type, the faster it will begin to overgrow with sediment. It is not recommended to use containers with a volume of more than 200-250 liters in everyday life for long-term storage of water.
Consideration should be given to the margin of safety of the overlap and bearing walls. The installation of the tank must be laid at the design stage of the house.
When using autonomous water supply, the volume of the storage tank, especially of the membrane type, should not exceed the debit of the well. If this rule cannot be observed, then the pump must be protected from idling.

Membrane-type storage tanks are limited in their volume and are not able to give up the entire supply of stored liquid. To form a stock of more than 300 liters, you will have to connect several tanks of a smaller capacity in parallel to each other.

General connection rules

A water tank is installed on a prepared site: concrete base tied with a foundation, or a reinforced metal frame made of profiled pipes. The design must withstand one and a half weight of the tank and the water in it when completely filled.

The inlet pipe can be of any suitable diameter, water is supplied under pressure. The outlet pipe and the pipe to the water supply are chosen with a diameter one and a half to two times larger than the cross section of the main line. Optimal size 32 mm.

Insulation, even of the highest quality, only slows down the decrease in temperature in the tank. To prevent freezing of water when installing the tank in an unheated attic or on the roof, any suitable heating system for pipes and the tank itself should be used.

With centralized water supply

Any type of storage tank connection requires check valve at the entrance to a house or apartment. It is the valve that will prevent the flow of stored water back into the pipeline, and not to the consumer.

Top connection

The tank is installed under the ceiling of the first floor, the floor above the bathroom and kitchen or in the attic. The tank should have a fitting at the top for water supply, another one a little higher for discharge into the sewer when overflowing, and a fitting at the very bottom for water intake.

After entering the coarse filter of the shut-off valve, the meter and the check valve, a tee is installed, from which the pipe goes to the tank inlet pipe, a shut-off valve or a controlled valve is installed in front of the fitting.

A shut-off valve is connected to the outlet fitting and the pipe is lowered back to the water supply, to which it is connected by means of a tee.

The excess discharge hose is lowered into the sewer or led out of the house into the front garden or drainage system.

To control the filling, a mechanical valve with a float is used, similar to those used in the toilet bowl.

To use the stored water, it is enough to open the outlet valve.

Bottom connection

Connection is identical to the first option. However, a pump must be installed at the outlet to create additional pressure in the water supply. Before each use of water, you will have to turn on the pump first.

A ready-made pumping station or a pump addition will help simplify life. expansion tank membrane type and pressure switch.

Bottom connection of storage tank with membrane

To connect the tank, only one pipe is used, connected to the water supply through a tee with a valve. The insert is also carried out after the filter, counter and check valve.

Before use, the pressure in the air chamber must be adjusted. This must be done strictly in accordance with the instructions for the selected model. Preliminary study normal pressure in the water supply, moreover, taking into account fluctuations during the day. As a result, the average value is taken, which is used to adjust the tank. This is the only way to use the maximum useful volume of the tank.

For autonomous water supply

As in the case of centralized water supply, there are several connection options.

Water tower

The storage tank is installed at a level of 15-20 meters above ground level on a reinforced tower or attic. Water from a borehole pump or pumping station is supplied directly to the tank, and from there it is distributed to the bathroom and kitchen in the house. The pressure in the system is provided by the height difference between the water level in the tank and the mixer tap in the house.

The disadvantage is the constant passage of water through the tank, which will cause sediment to accumulate over time, even if a filter system is pre-installed.

The advantage is the simplicity of the design and the minimum of expensive elements, with the exception of the tower structure itself and the obligatory insulation of the tank to protect it from freezing even when it is placed in the attic.

Bottom tank connection

The tank is installed flush with the pumping station or on the ground floor in the house. It is filled during normal operation of the pump due to water from the well. The limiter is a float switch.

This option saves with excessive water consumption and a decrease in the water level in a well or well. However, it is useless when the electricity is turned off, since a pump is required to supply the end user with water from the reserve.

Membrane storage tank

A membrane tank for storing water is installed after the pumping station and the check valve, with a bottom connection. If the pumping station for some reason does not work and does not maintain pressure in the system, then water comes from the storage tank.

Purpose and scope

Technological pressure tanks BT(N) are designed for storage of a liquid working medium under pressure and its subsequent use in technological schemes energy, housing and communal services, food, oil, chemical industries, and other industries.

Process pressure tanks BT(N) are made according to the strength calculation with a margin for corrosion from high-quality carbon or alloy steel with a thickness of 4 to 12 mm or stainless steel with a thickness of 3 to 10 mm.

General technical data of technological pressure tanks

Nominal volume (geometric capacity): from 100 l (0.1 m 3) to 32000 liters (32 m 3).
A number of conditional (nominal) pressures, MPa g: 0,1; 0,16; 0,25; 0,3; 0,4; 0,6; 0,8; 1,0; 1,25; 1,6; 2,0; 2,5.
Working environment temperature: from 0 to plus 200 °С.
Workspace: water, aqueous solutions, chemical reagents, other liquid media.
Climatic version according to GOST 15150: UHL 3.
Storage and transportation conditions according to GOST 15150: 5(0Ж4).
Permissible seismicity according to the MSK-64 scale: 7 points (as directed by the Consumer or design organization - up to 9 points).

Material design of technological pressure tanks

Material performance index	Material of structural elements of the tank				Estimated service life, years*
Material performance index	branch pipes	frame	flanges	supports	Estimated service life, years*
M1	St20	St20	St20	St3, St20	10-15
M2	St20, 09G2S	09G2S	St20	St3, St20	15-20
M3	AISI 304, 12X18H10T	AISI 304, 12X18H9T, 12X15G9ND	St20, 12Х18Н9Т	St3, St20	30-40

*Depending on tank thickness and corrosion margin (corrosiveness of the medium).

VERTICAL PRESSURE PROCESSING TANKS

Vertical pressure process tank BT(N) is a single-walled or double-walled welded structure, consisting of a cylindrical shell, upper and lower conical, toruspherical or elliptical bottoms, branch pipes for inlet and outlet of the working medium, fittings safety valve, drainage, other branch pipes as directed by the Consumer (design organization). The tank has three (four) vertical support-racks or support-paws.

Depending on the purpose of the tank and the conditions of its operation, at the direction of the Consumer (design organization), the following can be installed in the tank:

service hatch;
breathing tube (air vent);
equalizing line fitting;
recirculation pipe;
instrumentation fittings;
other fittings and pipes.

The lineup vertical pressure process tanks for design pressure
0.6 MPa g (6 kgf / cm 2) and 1.0 MPa g (10 kgf / cm 2)

Modification	Volume, m3	Diameter, D, mm	Height, H, mm	Height with supports, H1, mm		Weight for design pressure	TO ORDER *
BT(N)-0.1-0.6-V	0,10	425	800	1000	74/62	80/68
BT(N)-0.125-0.6-V	0,125	425	950	1150	83/69	90/76
BT(N)-0.16-0.6-V	0,16	530	850	1050	96/80	102/85
BT(N)-0.2-0.6-V	0,20	530	1000	1200	105/86	114/95
BT(N)-0.25-0.6-V	0,25	630	900	1100	123/100	130/108
BT(N)-0.32-0.6-V	0,32	630	1150	1350	140/110	150/125
BT(N)-0.4-0.6-V	0,40	630	1400	1600	155/125	170/140
BT(N)-0.5-0.6-V	0,50	700	1450	1700	205/165	230/190
BT(N)-0.63-0.6-V	0,63	700	1750	2000	230/185	260/215
BT(N)-0.8-0.6-V	0,80	800	1750	2000	260/210	290/240
BT(N)-1-0.6-V	1,0	800	2150	2400	290/230	330/270
BT(N)-1.25-0.6-V	1,25	900	2150	2400	370/305	415/345
BT(N)-1.6-0.6-V	1,6	1000	2200	2450	425/340	470/390
BT(N)-2-0.6-V	2,0	1100	2300	2550	490/395	540/445
BT(N)-2.5-0.6-V	2,5	1200	2400	2650	550/440	610/505
BT(N)-3.2-0.6-V	3,2	1300	2650	2900	640/515	840/645
BT(N)-4-0.6-V	4,0	1400	2850	3150	885/740	1040/820
BT(N)-5-0.6-V	5,0	1500	3100	3400	1020/850	1195/940
BT(N)-6.3-0.6-V	6,3	1600	3400	3700	1205/1005	1415/1110
BT(N)-8-0.6-V	8,0	1700	3800	4100	1395/1165	1650/1290
BT(N)-10-0.6-V	10	1800	4250	4550	1605/1335	1905/1485
BT(N)-12.5-0.6-V	12,5	1900	4750	5050	1860/1550	2215/1730
BT(N)-16-0.6-V	16	2000	5450	5750	2765/2180	3210/2625
BT(N)-20-0.6-V	20	2200	5650	5950	3190/2525	3690/3020
BT(N)-25-0.6-V	25	2400	5950	6250	3665/2895	4230/2460
BT(N)-32-0.6-V	32	2500	6950	7250	4445/3520	5150/4225

* When you click on the "Order" button, a request will be generated for invoicing or a commercial offer for the selected tank.

Examples of designation of vertical pressure process tanks when ordering

Vertical process pressure tank BT(N)-10-0.6-V-M2 TU 3600-003-95210823-2015

BT(N) - abbreviated tank marking;
10 - nominal volume, m 3;
0.6 – working pressure, MPa;
B - vertical;
M2 - index material performance.

HORIZONTAL PRESSURE PROCESSING TANKS

Horizontal pressure tank BT(N) is a welded structure, consisting of a cylindrical shell, right and left conical, toruspherical or elliptical bottoms, pipes for inlet and outlet of the working medium, fittings for a safety valve, drainage, and other pipes as directed by the Consumer (design organization). The tank has two saddle horizontal supports or cradles (for underground installation).