Installation
The regular way to install an auxiliary tank. Regardless of the type (see above), modern products can use both
horizontal and
vertical installation methods. It does not affect the main functionality, therefore, choosing a model according to this indicator is based on which option is most convenient for the intended installation location. We note only two specific points. Firstly, if the installation location allows, then it is better to use horizontal models for pumping stations, and vertical models for submersible pumps. Secondly, as it is used, air accumulates in the tank, which inevitably enters there along with water; it accumulates at the top of the tank and is much easier to bleed when installed vertically than when installed horizontally. However, this is only true for vessels with a special valve; in the absence of such a valve, the air can only be removed by completely emptying the tank (regardless of the method of installation).
Capacity
Nominal capacity of the water pressure tank or expansion tank.
For normal operation of the tank, this volume must be at least a certain value. However, the calculation methods depend on the type of container (see above). So, for water pressure tanks, the total number of consumers (total water consumption) and pump performance are taken into account, for expansion tanks — the volume of the circuit, the thermal expansion of the coolant and temperature fluctuations. Detailed recommendations about these calculations can be found in special sources; another option is to contact a heating/water systems expert. We only note that instead of one large tank, it is quite possible to install several small ones — in the second case, their total volume will have a value.
As for the specific volume values, in most water pressure tanks it ranges from
11 – 25 litres to more than 100 litres (
101 – 150 litres ,
151 – 200 litres and even
more). At the same time, even small water supply systems are often equipped with very capacious water pressure tanks — to have a supply of water in case of failures in the water supply. In turn, the expansion tank does not require significant volumes to perform its tasks, so such products do not differ in capacity — many models hold
10 litres or less(although there are
...exceptions).Membrane material
The material from which the internal elastic membrane of the tank is made.
Recall that in water pressure tanks (see "Type") this membrane has the form of a kind of balloon, which is filled with water so that the liquid does not come into contact with the metal walls of the tank. In turn, elastic transverse partitions are installed in the expansion tanks. However, in both cases, one of three materials is usually used for the membrane:
EPDM (ethylene propylene diene rubber),
Butyl (butyl rubber) or
SBR (styrene-butadiene rubber). Here is a more detailed description of each of these options:
— EPDM (ethylene propylene diene rubber). The most popular material for membranes nowadays is both in water pressure tanks and in expansion tanks. This prevalence is due to a combination of reliability, practicality, safety and affordability. Thus, EPDM has high elasticity and a wide operating temperature range, tolerates an average of up to 100K cycles of stretching/compression within acceptable limits, does not react with oxygen and industrial alcohols and can be used in drinking water supply systems. However, in terms of overall strength and resistance to diffusion, this material is somewhat inferior to butyl rubber (see below), but it is also much cheaper.
— Butyl (butyl rubber). High-quality material used primarily in water pressure tanks for cold wat
...er systems. One of the key advantages of butyl rubber is excellent gas tightness — several times higher than that of EPDM; simply put, much less air penetrates through such a membrane, which allows the tank to work longer without special maintenance. Also, this material is characterized by high strength, solvent resistance and hygiene; the latter allows the use of butyl rubber even in drinking water systems. The main disadvantage of this type of membrane is its high cost.
— SBR (styrene-butadiene rubber). A material primarily used in expansion tank membranes. This specialization is because SBR does not tolerate frequent tension compression very well and is better suited for static loads, which are just typical for such containers. At the same time, this material is reliable, elastic, resistant to water hammer, and very slightly permeable to air. Its unambiguous disadvantages include unsuitability for systems with drinking water.
