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October 12, 2016 23:18

Water pump for heating

In addressing the organization of heating their own homes the vast majority of homeowners prefer water heating system.Methods for the production of heat may vary - depending on the availability of energy sources, prevailing in the region fuels, profitability of a particular approach.That is, in fact, boiler can be installed, depending on the circumstances, gas, electric, solid fuel - long burning or automatic fuel supply, diesel and etc .But the distribution of thermal energy for on substituted in most cases is carried out by circulating through pipe coolant - water and specially selected technical liquids.

Water pump for heating

Water Pump for heating

When designing a water heating system, on their own or with the assistance of experts, it is necessary to competently approach to the choice of units, assemblies and components of the boiler and radiators up to pipes and the last gate - all should fullycomply with the planned parameters created by the system.One of the key roles played by the water pump for he

ating as system, equipped with a device for forced circulation always is stable in operation and high efficiency . Therefore, this publication will be devoted entirely to the nuances of pump devices, the criteria for their selection and the basic rules of installation.

So I need a circulating pump for heating water?

Article Contents

  • 1 So I need a circulating pump for heating water?
  • 2 How are circulating pumps?
    • 2.1 Video: the device and installation of circulation pump «Grundfos»
  • 3 How to select the circulation pump?
    • 3.1 Independent calculation of the parameters of the pump
      • 3.1.1 Calculator pump performance
      • 3.1.2 Calculator pressure created by the pump
  • 4 few tips on installing circulation pump
    • 4.1 Video: how to distinguish a real "the Grundfos" from counterfeiting

Surely , many of the budget owners will wonder - as if you can not do not "bother" with the pump.After all, in a small house with a lightly branched circuits, it is possible to arrange for heating circuit of natural circulation.

Yes, of course, such a possibility.To do this, you must correctly position the expansion tank, pick up a tube of appropriate diameter and mount them with certain bias optimally arrange the radiators.In a word, when talking about the simplicity of the system with natural circulation, this statement is very doubtful.

main advantage of natural circulation - not affection it to the power supply (if, of course, the boiler - volatile).In all the rest - it is significantly inferior to the forced circulation.

A simple heating circuit with natural circulation

simplest heating circuit with natural circulation

Thermal calculations show that even when most optimal conditions - high efficiency boiler, rational distribution of all components, clean, not overgrown deposits pipes and minimumshut-off or other reinforcing elements, the natural increase in pressure for through temperature difference and create a bias will be within 0.6 atmospheres.This is obviously not enough to overcome the strong hydraulic resistance in branched network or when the case of force majeure - happened blockage in the tubes with narrowed internal lumen or momentary stop gas boiler can lead to unbalance heating system and its long have « result in a sense."

So summarize the advantages and disadvantages of natural and forced circulation:

1. The advantages of natural circulation, as already mentioned, can be attributed only full-volatility and relative simplicity of the boiler piping.But the shortcomings - a list of:

- Need to use the pipes of different, including a sufficiently large diameter, which leads to a rise in the cost of the project and to difficulties in installation.The system requires very careful calculations of thermal , with exact observance of slopes, with the obligatory view of elevation location of some elements over others and other nuances.

- Transfer of heat energy over long distances (heights) is simply impossible.And the height and length of the generated circuit is limited.

- Low rate of natural movement of the coolant leads to completely unnecessary energy losses, the uneven distribution of the heat on for displaced and means - to reduce the total efficiency of the system and its economy.

- system with natural circulation is very difficult lends itself to any precise adjustments, optimize the distribution of heat flows on by displaced home.

2. And now - about forced circulation for heating circuits.

By its shortcomings attributed to the dependence on the availability of power - failures in the supply of electricity heating stops.

- Well, firstly, there is nothing stopping to organize the whole system in such a way that it can work in both modes - enough to install the pump unit on « return pipe » in front of the boiler.For example, Figure reproduced all the same pattern, but with an indication of the point of connection of the circulation pump.About binding order will be described below.

The same pattern , but with a circulating pump added to it

The same scheme, but with an added it circulator

- Second, we will agree that now is still not "the dawn of the electrification of the country."And, placing your hand on your heart, give yourself an honest answer to the question - how often, how regularly and for what duration in a particular area (city, village), turn off the electricity.If it is - only annoying episodes associated with certain emergency situations, all can be solved installing UPS systems.Power consumption in the circulation pump is generally very small, and even small UPS makes it easy to maintain in working order all the heating system.

Unless, of course, still there are places where electricity supply interruptions are systematic and long, in these communities points are definitely better organize heating scheme of natural circulation.

But the installation of pumping equipment at once gives heating system many advantages:

  • sharply reduced material consumption created system - large diameter pipes may not be necessary.And this is - still and facilitate their installation process.
  • Subject to measures necessary thermal insulation of pipelines , thermal energy can be transmitted over long distances and height, which is very important for the heating system in a large cottage, several storeys or extensions.
  • dramatically increases the efficiency of the heating system.Power consumption of the pump do not go to any comparison with the prize, which is achieved through improve system efficiency.
  • becomes possible to "zoning" of the heating system, the use of various heat options - Conventional radiators, convectors or water « warm floor".
  • heating system turns "flexible» - it easily lends itself to adjustments like generally , and on its separate areas.In any room, if desired , you can maintain the level of the individual heating.If necessary, you can quickly organize a redistribution of heat, with a focus on a specific area.
  • system with forced circulation is much easier to start up and regular maintenance.

Perhaps more convincing is not necessary: ​​the sidebar of circulation pump in hot water heating system can be viewed as an urgent necessity.If he still not worth it, then at the next maintenance of heating with natural circulation or its reconstruction, this question needs to be put into the category of priority.

And now closer to the pump on the device and select the appropriate model.

How are circulating pumps?

Almost all circulation pumps arranged by centrifugal pattern.In a special chamber (cochlea) rotates the impeller (impeller), which rejects the incoming fluid flow from the center to the edges of the chamber.Due to the centrifugal force during rotation of the wheel in the center 9na input ) created area vacuum, and the output - pressure.This difference is sufficient to create a flat, stable circulation flow in the heating circuit.

main problem that faced by developers of pumps of this type - to ensure a reliable electrical insulation.The first bold attempts were made still at the beginning of the XX century, when the first circulating pumps with a rotor, completely isolated from the water have been established (dry type).Somewhat later installation rotors located in the coolant medium (wet type) have been developed.

Of course, since the structure is constantly being improved, but all the same circuit circulation pumps are used to this day - "dry" and "wet."

Насосы "сухого" типа обычно достаточно массивны и требуют консольной установки

pumps "dry" type typically require massive enough and console installation

1. pumps "dry" type usually massive, rendered with a characteristic elongated in the direction of the engine compartment.They are quite noisy, and set up in a residential area, from this point of view impractical.

approximate device dry » pumps shown (region filled with coolant, designated green color):

Примерная схема устройства насоса "сухого" типа

exemplary pump assembly diagram" dry "type

motor ( poses 2.), which during its operation cooling is required, so most of it on set casing ( pos. 1), under which hidden fan.

rotor shaft dressed for ball bearings ( item 6.), And the interior of the electric motor is additionally protected ( poses 7.) O-ring (sometimes - gland seal types).

unit is connected to the motor housing of the pump ( poses . 9) through the metal (cast iron, brass) support flange ( poses . 3) with bolts or screws.Seal (pos. 8) provides tightness of the coupling.

The working shaft sleeve (Pos. 5), a pair of O-rings (pos. 11), made of a special material that ensures the tight fit them together for through difference external atmospheric pressure and the pressure created by the pump.Rings are made of little coal agglomerate, ceramic or, more rarely, of stainless steel.

Creating pressure is provided by the rotation of the working wheel (pos. 12), cast coming from the point of entry into the chamber (pos. 10) to the edges of the liquid "snail".

To prevent accumulation of air provided air valve (pos. 4).Often it is possible to set the control pressure gauge at the outlet - the figure shows muffled hole for it (pos. 13).

Pumps "dry" type characterized by high performance, their efficiency reaches 80%.But, at the same time, they require a lot more attention to himself - the O-rings to be periodically replaced as quickly wear out.Typically, these pumps are installed in separate rooms due to their noise and the need for special conditions.The usual scope of their application - powerful Heat points, or heating system, where the performance of pumping equipment is crucial.At home systems are used in exceptional cases - there is sufficient pump with "wet rotor".

2. Pumps "wet" type always much smaller (at equal performance indicators).If the "dry" pumps often require the installation of a cantilever, the "wet" simply cut into the pipeline.

"Классический" вид циркуляционного насоса с "мокрым" ротором

«Classic» view circulating pump with "wet" rotor

Additional cooling system they do not need - the excess heat is always drained fluid circulating through them.

Schematically device "wet" circulating pump can portray following way :

Схема устройства насоса с "мокрым" ротором

Driving pump unit with "wet" rotor

motor stator (. Pos 4) this case is located in a sealed metal "glass "(pos. 8).The rotor also has the usual engine collector-brush mechanism, Electrotechnical it is organized differently, as rotating in a liquid coolant medium (shown as , as in the first scheme, a greenish background).The rotor shaft (pos. 7) is supported on both sides on the bearing sleeve (pos. 2), and the heat transfer fluid in the circuit acts as a lubricant never drying.That is why it is important that the air does not accumulate and bearings have always been in the "wet" state inside the pump.To achieve this, the motor shaft should be in any position of the pump to remain exclusively in the horizontal position, and the air outlet is provided screw plug valve (pos. 6), the sealing of which is provided by laying in a twisted state ( on. 5 )

As for the rest - the same camera- "snail" in iron or brass body (. item 1), the impeller (item 3.), which creates a centrifugal acceleration of liquid and pressure drop across the inlet and outlet of the pump ..

dignity - do not need fancy and wearing seals on rotating sites.Conventional gaskets are fixed connections (pos. 10) completely solve the problem of sealing the pump.

rotor rotation is in a liquid medium, chto¸ course, due to increased water resistance significantly reduces the efficiency of this pump (usually the figure is around 50%). Nevertheless , the use of "wet" pump is justified in terms of the individual heating system:

  • These pumps run almost silently - even installed in residential areas (for example, the collector « warm sex"), they do not bringany sensation of discomfort.
  • Low efficiency to fully pay off the low energy consumption.Thus, the initial performance category pumps, which are more likely used for heating small houses and cottages have a nameplate wattage from 25 to 50 watts - compared with a small light bulb.
  • Subject to operational requirements, they can last for decades, completely without requiring any intervention - preventive maintenance or repair.The main thing - do not leave a dry rotor.As for the rest, by and large account , there is simply nothing to break or abrasions (unlike electric motors collector who wear brush , or "dry" pump circuit to gradually abrade the sealing rings).

So, no need to split hairs too much - for home autonomous heating systems will be quite enough pumps with "wet" rotor.

They are comfortable yet and what have modular design - can be easily disassembled into its component units, each of which, in the event of failure, may be replaced the serviceable.

Typically, these pumps have a modular construction

Typically, these pumps have a modular design

In the figure the:

1 - working chamber of the pump housing.