Stable operation of an autonomous water supply system is impossible without a hydraulic accumulator. This device, also called a membrane tank, solves several important tasks at once. It maintains stable pressure in the pipeline, protects the pump from frequent switching on and off, and creates a small supply of water in case of a power outage.
The most important parameter that determines the efficiency of the entire system is the volume of the tank. How not to make a mistake with the choice and buy a hydraulic accumulator that is ideal for your needs - read in this article.
The role of the accumulator in the stable operation of the water supply system
The hydraulic accumulator acts as a buffer tank, which smooths out pressure drops and reduces the load on the pumping equipment. Its installation allows:
- Avoid water hammer that occurs when the pump starts or stops abruptly.
- Reduce the number of pump starts, which significantly extends its service life.
- Ensure stable water pressure in the system.
- Keep a supply of water in case of a short power outage.
- To compensate for the thermal expansion of water in hot water supply and heating systems.
So, hydraulic accumulators – not just storage tanks, but key elements that ensure comfort, reliability and durability of the entire water supply system.
The principle of operation of a hydraulic accumulator
Structurally, a hydraulic accumulator is a strong, hermetic metal tank, divided from the inside into two chambers by an elastic membrane. Water from the source enters one chamber (the inner space of the membrane), and air pumped under pressure is in the other (between the tank walls and the membrane).
The device's operating process consists of several sequential stages:
- The pump begins to pump water into the rubber balloon inside the tank, causing it to expand.
- As the volume of water increases, the air around the membrane is compressed, and the pressure in the system gradually increases.
- When the readings reach the upper limit set by the pressure switch, the automatic system de-energizes the pump.
- When the tap is opened, compressed air begins to pressurize the membrane, pushing water into the pipeline to the consumer.
- The water level decreases, the pressure drops to the lower limit, after which the relay closes the contacts again, starting a new pumping cycle.
Thanks to this logic of interaction between liquid and air, water does not come into contact with the inner metal walls of the housing, which protects it from the appearance of foreign odors or rust.
Types of hydraulic accumulators
Depending on their design and purpose, hydraulic accumulators are divided into several types. The key differences relate to:
- Installation type. Vertical and horizontal. The choice depends on the free space in the room.
- Membrane type. Tanks with a replaceable membrane (pear) and with a fixed diaphragm. Replaceable membranes are easy to replace when worn.
- Purpose: For water supply systems (usually blue or white) and for heating systems (red).
In terms of volume, the line covers the range from small household models of a few liters to industrial storage tanks of several thousand liters.
How to calculate the volume of a hydraulic accumulator
Choosing the right size of the hydraulic tank is the most important step. A tank that is too small will lead to frequent pump starts and rapid wear, while a tank that is too large will lead to unnecessary financial expenses and water stagnation.
Dependence of volume on pump performance
The main rule of engineering is that the pump should not be turned on more than 20-30 times per hour. The higher the performance of the pumping equipment, the larger the tank volume should be installed.
If the pump delivers 3 cubic meters per hour, it needs a tank of 80-100 liters. For a capacity of 1-1.5 cubic meters per hour, 24-50 liters is enough. Ignoring this rule leads to premature failure of the automation and the pump itself.
Calculation for a private house and apartment
For domestic use, you can rely on the number of water points and the size of the family that permanently lives in the home.
In apartments where a hydraulic accumulator is installed to stabilize the pressure in the central network, compact 24-liter models are usually sufficient. They are easily hidden in plumbing cabinets and ensure smooth operation of the equipment.
For a private house with an autonomous system, the calculation should be more detailed:
- A family of 1-2 people (kitchen, bathroom, washing machine). The basic solution will be a tank with a volume of 24-50 liters.
- A family of 3-4 people (a second bathroom, shower, lawn watering are added). It is recommended to purchase models with a capacity of 50-80 liters.
- Large cottage (5 people or more, several bathrooms, swimming pool, intensive automatic watering system). Requires installation of a vertical or horizontal tank of 100-150 liters.
If your area experiences frequent power outages, choose a larger tank to have the necessary water supply for several hours.
Hydraulic accumulator paired with a pump
These two elements work inextricably together. The pump creates the flow, and the tank accumulates and stabilizes it. The correct connection ensures an uninterrupted supply of resources.
Selection of a hydraulic accumulator for a submersible pump
A deep well pump usually has a high capacity of 3 to 5 cubic meters per hour. It pumps liquid with a powerful jet. To smooth out this flow and give the equipment a rest between cycles, a large tank is needed.
For well systems, we recommend tanks from 100 liters. This relieves the load on the automation and prevents dry running in the event of a sharp drop in the water level.
Pressure switch settings
The pressure switch controls the start and stop of the pump. For the system to work correctly, the air pressure in the empty accumulator must be correctly adjusted using a conventional automobile pressure gauge.
Basic setting rule: The air pressure in the dry tank should be 10% (or 0.2 bar) less than the pump start pressure set on the relay.
Tank materials and anti-corrosion coating
The housing operates in conditions of constant humidity and temperature changes. Therefore, a high-quality accumulator is made of carbon steel. An epoxy anti-corrosion coating is applied to the outside. It protects the metal from rust in damp basements.
The flange through which water enters the tank is the weakest point. A cheap thin flange made of ferrous metal will rot in three years. We use galvanized or stainless steel, which will last for decades. The membrane itself is made of food-grade EPDM rubber or butyl.
These materials do not emit harmful substances and withstand multiple stretching cycles without losing elasticity.
Installation and connection of the hydraulic accumulator
The accumulator is connected to the pipeline through a fitting or flange connection near the pump and pressure switch. Usually - at the outlet of the pumping station. Vertical models are installed on a flat surface, horizontal ones are fixed on supports to avoid load on the connection pipe.
Before the first start-up, check the air pressure in the chamber through the nipple. It should correspond to the passport value and be slightly lower than the pump switching pressure on the relay. Incorrectly set air pressure is one of the most common reasons why a newly installed system does not work as expected.
Maintenance: membrane replacement, air pumping
The accumulator is a device that requires regular maintenance. Preventive checks of the pressure in the air chamber should be carried out at least twice a year. To do this, completely drain the water from the system, leaving the taps open, and use a pressure gauge to measure the readings on the nipple. If necessary, air is pumped in with a conventional car or bicycle pump.
If water starts to flow out of the nipple when you press it, this is a direct sign that the internal membrane has ruptured. It is a consumable item and can be easily replaced by yourself. To do this, unscrew the flange bolts, remove the old damaged rubber bulb, thoroughly clean the inner walls of the tank from dirt and rust, insert a new cylinder of the appropriate volume and clamp the flange back.
Typical mistakes when choosing a hydraulic accumulator
To avoid wasting money, remember the most common mistakes:
- Too small a volume. The pump will turn on every time you fill a glass of water, which will cause it to fail quickly.
- Too large a volume for the system. If the pump is underpowered, it will not be able to create the pressure to fill a large tank.
- Incorrect air pressure. Too high a pressure will prevent water from filling the tank, and too low a pressure will cause the membrane to rupture.
- Ignoring membrane quality. Unenvironmentally friendly materials can contaminate drinking water.
When choosing a water accumulator, it is always better to have a small reserve of volume than to take "close". But it is best to trust the professionals. Experienced UKSPAR managers will help you purchase the ideal model, taking into account all the features of your system.
In the UKSPAR catalog, the price for each accumulator is up-to-date and reasonable. Choose proven equipment for stable water in your home!
