RU2607881C1 - Admixing pump unit in central heating systems local networks - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: this technical solution relates to power engineering and applicable in area of centralized heat supply system of local and areal heat supply networks. Admixing pump unit in central heating systems local networks is characterized by fact, that admixing pump suction pipe guide branch pipe is welded-in into local area network CHS reverse pipeline against carrier flow, to create overpressure in admixing pump suction pipe, guide branch pipe cross-section area is in two times less than suction pipe cross-section area, to reduce excessive pressure in admixing pump suction pipe, and guide branch pipe on admixing pump pressure pipe is welded-in into local area network CHS supply pipeline along heat carrier flow in order to reduce turbulence in hot and cold heat carriers admixing zone, guide branch pipe cross-section area is twice less than admixing pump pressure pipe cross-section area in order to add additional energy to coolant flow in local area network supply pipe.

EFFECT: centralized heat supply of local and areal heat supply networks.

1 cl, 3 dwg

Description

This technical solution relates to the energy sector and is applicable in the field of district heating of local and local heating networks.

A local heating network is a heating system for single-standing buildings or a group of rooms in a building.

A local (quarterly) heat network integrates several local heat networks. The use of a mixing pump in local heating networks serves to reduce the temperature of the coolant inside the network and bring it to sanitary standards. The temperature should not exceed 95 ° C.

Currently, to lower the temperature of the coolant in the local heating network, UTE type elevator units manufactured according to the TU400-38-111-91 standard are used. The design and purpose of the elevator units are described on the website zhkx / 17-elevatornyi-uzel-elevator, which can be considered as a prototype of the proposed technical solution. The disadvantages of this prototype are:

- limited bandwidth;

- lack of sufficient coolant pressure necessary for pumping the local network;

- the need to maintain a pressure differential between the supply pipe and the return pipe at least 0.25MPa;

- the need to maintain a sufficiently high overpressure of 0.7 MPa and higher in the heating system.

The installation of a mixing pump between the supply and return pipelines at the Central Heating Center (hereinafter the CTC) of the local network solves the problems associated with the installation of an elevator assembly in the CCP. But with test installations in the central heating unit of the mixing pump between the return pipe and the supply piping, it turned out that when the mixing pump is started, a water hammer occurs that can destroy the heating system. By starting the mixing pump on a closed valve and opening it smoothly, water hammer can be avoided, but the turbulence that occurs in the mixing zone in the supply pipe damped the energy of the heat carrier flows from the heat-generating source and the flow from the mixing pump, which, in turn, prevented the coolant from pumping in the local network .

To eliminate turbulence in the coolant mixing zone in the supply pipe to the central heating system, I have developed and implemented a system for inserting a mixing pump into the local heating network through guide pipes. In the insertion zone of the suction pipe of the mixing pump, a guide pipe is welded into the return pipe, directed against the direction of movement of the coolant. This position of the guide pipe creates additional pressure in the suction pipe of the mixing pump. But to reduce the excess pressure in the suction pipe of the mixing pump, the cross-sectional area of the guide pipe is reduced by half in relation to the cross-sectional area of the suction pipe of the mixing pump. In the insertion zone of the pressure pipe of the mixing pump into the supply pipe, the guide pipe is welded along the heat carrier. This position of the guide pipe prevents the occurrence of turbulence in the mixing zone of the coolant. The cross-sectional area of the guide pipe is halved in relation to the cross-sectional area of the pressure pipe of the mixing pump. This technical solution allows you to avoid water hammer at the time of starting the mixing pump, increases the excess pressure in the pressure pipe of the mixing pump, which in turn can significantly increase the flow rate of the coolant in the supply pipe of the local heating network. It should be noted that the above technical solutions increase the mixing pump performance by 30%.

The installation of the mixing pump in the local networks of central heating systems, in comparison with the prototype, has the following advantages:

- simplification of the design of the local heating network due to the lack of elevator nodes within the local network;

- due to the reuse of thermal energy of the coolant, thermal energy savings of more than 30% of the calculated values are achieved;

- due to an increase in the flow rate of the coolant, the efficiency of the air heater installations is significantly increased;

- the excess pressure inside the local network decreases to 0.3-0.4MPa;

- the pressure drop between the supply pipe and the return pipe is reduced to 0.04 MPa;

- there is the possibility of a simplified transfer of the local heating network to the "weekend" and "working" day.

The economic effect of this technical solution is based on the reuse of thermal energy of the coolant returned by the consumer to the heat-generating source, where the thermal energy is lost in the storage pools and sumps.

Saving thermal energy in the local heating network, when using a mixing pump, is achieved by reducing the consumption of thermal energy coming from a heat-generating source. This loss of thermal energy is compensated by a 4-fold increase, behind the mixing unit, of the amount pumped through the local heat network of the coolant. This condition is satisfied by the installation of a mixing pump in the heating network.

It should be noted that the dimensions shown in the graphic part of the application are acceptable only for the local heating network of IMZ OJSC, Ishimbay, the Republic of Bashkortostan, Russia, where a mixing pump has been installed and has been operating since 2010. When developing a project for installing a mixing pump in a local or local heating network, one should proceed from the “Technical Assignment” data for this local or local heating network. The hourly flow rate of the coolant in the local or local heating network, which is multiplied by a factor of 4, is taken as the basic calculated value. Based on the result, you should choose the pump capacity. Based on the technical data of the pump, the diameters of the suction and pressure pipes are selected. The cross-sectional area of the guide pipes should be half the cross-sectional area of the suction and pressure pipes of the mixing pump. However, reducing the diameter of the guide pipes in the local heating network is not necessary.

A brief description of the drawings.

The technical essence of the proposed solution is illustrated by drawings in which:

Figure 1 - installation of the mixing pump, side view;

Figure 2 - installation of the mixing pump, top view;

Figure 3 - circuit insertion guide pipes.

The mixing pump (Fig. 1, pos. 1) is installed in the central heating system of the local heating system. The coolant through the return pipe (Fig. 3 pos. 3) enters through the guide pipe (Fig. 3 pos. 7) into the suction pipe (Fig. 3 pos. 6) of the mixing pump (Fig. 1 pos. 1), which is under overpressure pumps the coolant through the pressure pipe (Fig. 3 pos. 5) and the guide pipe (Fig. 3 pos. 4) into the supply pipe (Fig. 3 pos. 2), where the flows of cooled and hot coolants are mixed. The guide pipe (Fig. 3, pos. 7) in the return pipe (Fig. 3, pos. 3) is directed against the direction of flow of the coolant, which creates a block in the suction pipe (Fig. 3, pos. 6) of the mixing pump (Fig. 1, pos. 1) and increases pump performance. The guide pipe (Fig. 3 pos. 4) on the supply pipe (Fig. 3 pos. 2) is directed along the flow of the coolant, which avoids turbulence in the mixing zone of the cooled and hot coolants. The arrows in (Fig. 2 and Fig. 3) show the direction of movement of the coolant. The cross-sectional area of the guide pipes (Fig. 3, item 4 and. 3, item 7) is two times smaller than the cross-sectional area of the pressure pipe (Fig. 3 item 5) and the cross-sectional area of the suction pipe (Fig. 3 item 6) of the mixing pump .

Claims (1)

The mixing pump installation in local networks of central heating systems is characterized by the fact that the guide pipe of the mixing pump suction pipe is welded into the return pipe in the central heating circuit of the local network against the flow path of the coolant, to create a backwater in the mixing pump suction pipe, the cross-sectional area of the guide pipe is smaller than the cross-sectional area of the suction pipe twice to reduce excess pressure in the suction pipe of the mixing pump, and the guide pipe on the pressure pipe of the pump mixing is welded into the supply pipe to the central heating unit of the local area network along the flow of the coolant to reduce turbulence in the mixing zone of hot and cold coolants, the cross-sectional area of the guide pipe is half the cross-sectional area of the pressure pipe of the mixing pump to give additional energy to the coolant flow in the supply pipe of the local network.

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