EP0945686A2 - Pressure control device with a pump mounted in the fluid chamber - Google Patents

Abstract

The pressurizer has an expansion tank (1) having a liquid-container chamber connected via a connecting pipe (3) to a heating or cooling circuit. An overflow valve (5) is positioned on an overflow pipe (4) leading to the chamber. The overflow pipe branches off from the connecting pipe or is connected to the heating or cooling circuit. A pump (6) pumps liquid from the chamber into the connecting pipe, and is situated inside the chamber which is formed by an extensible bubble (2) or is defined by a membrane in the expansion tank.

Description

The present invention relates to a pressure maintaining device for closed heating or cooling circuits, as in the preamble of independent claim 1 is defined.

Changes in system temperature in closed heating or cooling circuits lead to volume fluctuations the circulating fluid and thus to pressure changes in the Circulation. Because too high pressures immediately lead to leaks and destruction and low pressures evaporation phenomena, combined with cavitation and condensate blows, cause it is necessary to a certain operating pressure to adhere to. For this purpose, pressure maintenance devices used when the volume of the circulatory fluid increases Take the excess volume from the circuit and this via an overflow valve to an expansion tank convey where there is air and atmospheric Pressure is stored, and when the volume of circulatory fluid decreases the missing volume from the expansion tank respectively.

The scheme of such a known pressure maintaining device, for example a PNEUMATEX Transfero system from Stücklin & Cie AG, Füllinsdorf / CH, shows Fig. 1. In this Figure 20 denotes a heating or cooling circuit, 1 ' an expansion vessel with an expandable bladder 2 ' Liquid intake chamber, 3 'a connecting line, through the bladder 2 'connected to the heating or cooling circuit 20 is, 6 'a pump for pumping liquid from the bladder 2 'via the connecting line 3' in the heating or cooling circuit 20, 7 'a check valve and 5 'on an overflow line 4' between the connecting line 3 'and the bladder 2' arranged overflow valve. Also shown are two shut-off valves 21 'and 22' and a filter 23 '.

If the desired operating pressure in the heating or cooling circuit 20 exceeded by a certain tolerance value the overflow valve 5 'opens, so that circulating liquid, usually water into which bladder 2 'flows. As soon as the pressure has dropped sufficiently, closes the overflow valve 5 'again. If, on the other hand, the operating pressure falls below a certain tolerance value, as long as the pump 6 'is switched on and thus liquid conveyed by the bladder 2 'into the heating or cooling circuit 20, until the pressure is raised enough.

Instead of a bladder, the expansion vessel can also have a liquid receiving chamber have delimited by a membrane which is the inside of the expansion tank divided. There are also open expansion vessels without stretchable inner parts used.

The pressure maintenance devices described have for certain Applications several disadvantages. So their structure is relative expensive because the expansion tank and the remaining components are arranged separately. This also leads to one great piping effort and usually for use separate chassis for expansion tank and pump etc. and thus to a large transport volume. Because the piping are relatively long, they generate considerable resistance and as a result a negative pressure, which occurs when overflowing and suction through the pump to an air pool can lead in them. This can cause noise and conveying problems caused by the pump during suction. Another disadvantage is that some of them depend on the type of pump despite the noise insulation, annoying pumping noises. Also is the commissioning of such pressure maintenance devices relatively complex, because first the liquid absorption chamber a specialist must be vented. Furthermore, they tend during operation for gas accumulation in the liquid receiving chamber.

Given the disadvantages of the previously known, described above Pressure maintenance devices is the invention based on the following task. A pressure maintenance device must be created of the type mentioned at the beginning, with less piping more compact and simpler and quieter can be operated as comparable previous pressure maintenance devices.

This object is achieved by the pressure maintaining device according to the invention solved as in the independent claim 1 is defined. Preferred design variants result itself from the dependent claims.

The essence of the invention is that in a pressure maintaining device for closed heating or cooling circuits, with an expansion vessel, which is a liquid absorption chamber includes a connection line a heating or cooling circuit can be connected, one Pump for pumping liquid from the liquid receiving chamber into the connection line inside the liquid absorption chamber is arranged. The pressure maintaining device comprises further a leading to the liquid receiving chamber Overflow line that branches off from the connecting line or can be connected to the heating or cooling circuit overflow valve arranged on the overflow line and a control device.

This means that the pump is inside the liquid absorption chamber is arranged, on the one hand, the piping effort kept low and the pressure maintaining device compact be built and on the other hand, the pumping noises the liquid surrounding the pump in the liquid receiving chamber and suppresses the outer wall of the expansion tank.

In a first advantageous embodiment, the Liquid absorption chamber formed by an expandable bladder, while in a second advantageous embodiment the fluid intake chamber in the expansion tank is delimited by a membrane. The bladder or membrane also cause pump noise suppression here.

Is a high fluid holding capacity of the pressure maintenance device required, these can have two or more expansion vessels each with a liquid intake chamber, through one or more connecting lines are connected. In general, only the liquid receiving chamber one of the expansion vessels with a connection line to the heating or cooling circuit and provided with an internal pump. But if a very large liquid volume flow is required, then advantageously in one or more further expansion vessels internal pumps available to the Heating or cooling circuit are connected. To this Way, a high fluid absorption capacity with the Possibility of a large liquid volume flow combined become.

The connecting line and the overflow line are advantageous the pressure maintaining device according to the invention from above here in or to the expansion tank, and a possible Connection piece for a connecting line Another expansion tank is at the bottom of the expansion tank arranged. It is thus possible to use the liquid intake chamber relatively easy to degas. Also can a gas accumulation in the connecting line and further Expansion tank are largely avoided.

Preferably is on the overflow line between the overflow valve and the liquid receiving chamber is a gas collection container arranged, in which the overflow line opens and a passage to the liquid receiving chamber having an opening cross-section that is smaller than the inner cross section of the overflow line, at one located higher than the mouth of the overflow line Location of the gas collection container, especially the highest point of the gas collection container, a degassing valve is arranged.

With the help of such a gas collection container, the interior the liquid intake chamber quickly and comprehensively be degassed. When the liquid passes from the heating or cooling circuit in the expansion tank finds a pressure drop and thus, according to Henry's law, degassing instead, with the escaping gas in the gas collection container and if necessary accumulates in the expansion tank at the top. Becomes now the overflow valve is opened, liquid flows into the Gas collection container and jams at the narrow passage. Thereby the accumulated gas is removed from the Ejected gas collection container.

The overflow valve is normally only opened when if the desired operating pressure in the heating or cooling circuit exceeded by a certain tolerance value becomes. For quick degassing of the pressure maintenance device The overflow valve can be reached during commissioning but initially operated increasingly by the control device become. To maintain the operating pressure then the pump is inevitably put into operation.

The volume loss resulting from the degassing the pressure maintaining device has to compensate for the circulating fluid preferably a liquid make-up device on.

In the following the pressure maintaining device according to the invention with reference to the accompanying drawings described two embodiments in more detail.

Fig. 2 -

eine teilweise geschnittene Ansicht eines ersten Ausführungsbeispiels der erfindungsgemässen Druckhaltevorrichtung und

Fig. 3 -

eine teilweise geschnittene Ansicht des oberen Teils eines zweiten Ausführungsbeispiels der erfindungsgemässen Druckhaltevorrichtung;

Show it:

Fig. 2 -

a partially sectioned view of a first embodiment of the pressure maintaining device according to the invention and

Fig. 3 -

a partially sectioned view of the upper part of a second embodiment of the pressure maintaining device according to the invention;

Figure 2

The pressure maintaining device shown comprises an expansion vessel 1 with two lids 16 and 17, between which an expandable bladder 2 is arranged for liquid absorption is. The bladder 2 is gas-tight with the two lids 16, 17 connected and via a connecting line 3 to a heating or cooling circuit can be connected. From the connection line 3 branches outside the expansion tank 1 Overflow line 4, which is a gas collection container 40 to an opening in the upper lid 16 and thus to Bubble 2 extends. A degassing valve 41 closes the Gas collection container 40 upwards. On the overflow line 4 an overflow valve 5 is arranged, which is too high Pressure in the connecting line 3 or, controlled by a Control device arranged outside the expansion vessel 1 9, opens. The overflow valve 5 can for example be a solenoid valve. At the end of the connecting line 3 inside the bladder 2 is a pump 6 for pumping liquid attached by the bladder 2 in the connecting line 3.

Furthermore, the expansion vessel 1 has in the vicinity of it highest point a degassing and gassing 18 for degassing and fumigation of the space between bladder 2 and the outer wall 19 of the expansion tank 1.

A connecting piece 8 for a connecting line to one another expansion vessel is attached to the lower cover 17 and communicates with the bladder interior.

The expansion vessel 1 has three vessel feet, whereby only feet 13 and 14 are visible here. In the base of the vessel 13 is a weight measuring device 131 for determination of the liquid level in the bladder 2 integrated.

Measuring the content of the bladder 2 by weight can do this used to run dry the pump 6 by switching off when falling below a certain weight prevent.

This first embodiment of an inventive Pressure maintenance device works essentially like that Known pressure maintenance devices described in the introduction: if the desired operating pressure in the heating or Cooling circuit exceeded by a certain tolerance value the overflow valve 5 opens, so that circulating liquid, usually water, into which bladder 2 flows. As soon as the pressure has dropped sufficiently, closes the overflow valve 5 again. If, on the other hand, the operating pressure falls below a certain tolerance value, as long as the pump 6 is switched on and thus liquid from the bladder 2 via the connecting line 3 in the heating or cooling circuit until the pressure increases enough is.

Figure 3

The second embodiment shown here of an inventive Pressure maintaining device differs from the first embodiment in that on the overflow line 4 between the overflow valve 5 and the bladder 2, a gas collecting container 10 is arranged, which leads to the bladder 2 has a passage 101 with an opening cross section, which is smaller than the inner cross section of the overflow line 4. At the highest point of the gas collection container 10, a degassing valve 12 is arranged. Furthermore is on the connecting line 3 between the bladder 2 and the A check valve 7 branches off the overflow line 4 attached, the liquid from the bladder 2 to the branch, but not in the opposite direction.

Thanks to this specially shaped gas collection container, the The interior of the bladder 2 can be degassed quickly and comprehensively, which means there is no manual degassing during commissioning can be. That after the transition of the liquid from the heating or cooling circuit into the expansion tank 1 gas escaping from the liquid due to the pressure drop accumulates in the gas collection container 10 above. Now will that Overflow valve 5 opened, liquid flows into the gas collection container 10 and jams at the narrow passage 101. This causes the accumulated gas to pass through the degassing valve 12 ejected from the gas collection container 10.

To quickly degas the pressure maintaining device overflow valve 5 initially operated by the control device. This inevitably leads to increased activity the pump and to an increased fluid circulation and thus faster degassing.

• In der Anschlussleitung 3 kann ein mit der Steuereinrichtung 9 oder manuell betätigbares Absperrventil angeordnet sein.
• Die Überströmleitung 4 kann anstatt von der Anschlussleitung 3 abzuzweigen direkt an den Heizungs- oder Kühlkreislauf anschliessbar sein.

In addition to the pressure maintaining devices described above, further design variations can be implemented. Here are also explicitly mentioned:

• A shut-off valve which can be actuated with the control device 9 or manually can be arranged in the connecting line 3.
• The overflow line 4 can be connected directly to the heating or cooling circuit instead of branching off from the connecting line 3.

Claims (10)

Pressure maintenance device for closed heating or Cooling circuits, with an expansion vessel (1), the comprises a liquid receiving chamber, which is connected via a connecting line (3) to a heating or cooling circuit can be connected, an overflow valve (5) on a overflow line leading to the liquid receiving chamber (4) is arranged, the overflow line (4) from the Branch line (3) branches or to the heating or Cooling circuit can be connected, a pump (6) for pumping of liquid from the liquid receiving chamber into the Connection line (3) and a control device (9), thereby characterized in that the pump (6) within the Liquid intake chamber is arranged. Pressure maintaining device according to claim 1, characterized characterized by the liquid absorption chamber an expandable bladder (2) is formed or in the expansion vessel (1) is delimited by a membrane. Pressure maintaining device according to claim 1 or 2, characterized in that on the connecting line (3) a check valve (7) is arranged, the liquid in Direction of the liquid absorption chamber, but not in the opposite direction, lets flow through, with the check valve (7) between the liquid receiving chamber and the branch the overflow line (4) is arranged when the Overflow line (4) branches off from the connecting line (3). Pressure maintaining device according to one of claims 1 to 3, characterized in that they have two or more expansion vessels each with a liquid absorption chamber, through one or more connecting lines are interconnected. Pressure maintaining device according to one of claims 1 to 4, characterized in that the connecting line (3) and the overflow line (4) from above into or on the Expansion vessel (1) are guided and a connecting piece (8) for a connecting line to another expansion tank be arranged at the bottom of the expansion tank (1) can. Pressure maintaining device according to one of claims 1 to 5, characterized in that on the overflow line (4) between the overflow valve (5) and the liquid receiving chamber a gas collection container (10) is arranged in the the overflow line (4) opens and that to the liquid receiving chamber towards a passage (101) with an opening cross section has that is smaller than the inner cross section the overflow line (4), one being higher than that Mouth of the overflow line (4) located the gas collection container (10), especially the highest point of the gas collection container (10), a degassing valve (12) is arranged is. Pressure maintaining device according to one of claims 1 to 6, characterized in that the pump (6) on the liquid receiving chamber side End of the connecting line (3) is arranged. Pressure maintaining device according to one of claims 1 to 7, characterized in that the expansion tank (1) has at least one vessel foot (13, 14) and in the or a vessel base (13) a weight measuring device (131) for determining the liquid level in the liquid receiving chamber is integrated. Pressure maintaining device according to one of claims 1 to 8, characterized in that it is a protective device to prevent the pump (6) from running dry. Pressure maintaining device according to one of the claims 1 to 9, characterized in that they have a liquid make-up device having.

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