NL1036252C2 - HEATING SYSTEM WITH EXPANSION DEVICE. - Google Patents

Description

HEATING SYSTEM WITH EXPANSION DEVICE

The invention relates to a heat transport system with an assembly of a cold or heat source and a pipe system with heat exchangers connected thereto, and an expansion device connected to the assembly. The heat transport system is then of a type that functions with a closed, liquid-circulating fluid circuit along the heat exchangers and the cold or heat source.

In the liquid circuit, on the one hand, a heating boiler or cold pump or the like is included as a source, in which heat or cold is supplied to the liquid circulating in the circuit. On the other hand, radiators and / or convectors or other heat exchangers are included in the liquid circuit, by means of which cold or heat is released from the liquid to be cooled or heated spaces.

An air transport system can be used instead of or as an addition to convectors and radiators.

The invention also relates to a cooling installation, but because of the readability of the application, the invention is described below only in connection with a heating device.

Devices of this type comprise an expansion device, often comprising a liquid reservoir or expansion vessel, in which the additional volume of liquid is taken up that results from expansion due to heating of the liquid. Upon cooling of the liquid in the liquid circuit in the assembly, liquid is again brought back from the reservoir into the circuit in the assembly to compensate for the volume reduction due to this cooling.

1036252 2

A safety valve is installed to prevent overpressure in the fluid circuit or the assembly. A heating device of this kind is described in the European patent (application) and EP0947777 and EP0740759 or NL9400106.

A feature of this expansion device known from the aforementioned documents is that there is a lower pressure in the reservoir or expansion vessel with respect to the pressure in the liquid circuit (assembly). For this reason, a pump is used to return liquid to the assembly with the liquid circuit during cooling. This pump is located in a connecting line between the assembly with the liquid circuit and the expansion device, and is intended to bridge the pressure difference between the liquid in the reservoir of the expansion device and the liquid in the assembly with the liquid circuit. For taking up liquid from the assembly with the fluid circuit during heating of the fluid, as a result of the volume increase, use is made of the higher pressure in the assembly with the fluid circuit. With the aid of opening a valve present for this purpose in the connecting line between the assembly with the liquid circuit and the expansion device, the liquid in the expansion device can flow in from the assembly with the liquid circuit, where the higher pressure prevails, to the expansion vessel or reservoir of the expansion device, until the pressure in the assembly with the liquid circuit has reached a desired lower value.

The pump and the valve can be controlled by a switching mechanism or control, whereby a small pressure reduction or increase in the assembly with the liquid circuit the pump resp. the valve activates. For this purpose, the valve must be equipped with an auxiliary drive. The pressure control of the assembly with the liquid cycle has thus become automatic. The pressure of the liquid in the assembly will remain constant within a desired, often small bandwidth.

A major problem in dimensioning the pump and valve in the known configurations is that undesired hydraulic effects can occur. If a pumping capacity is too large, a pressure can rise uncontrollably high in the assembly with the liquid circuit. A pump capacity chosen too small has the consequence that the cooling process in the fluid cycle assembly cannot be followed, due to the volume decrease of the fluid, resulting in too low a pressure in the fluid cycle assembly.

A similar problem applies to the valve in the connecting line between the assembly with the liquid circuit and the expansion device. Too large a dimensioned valve causes the pressure in the assembly with the liquid circuit to drop rapidly in an uncontrolled manner. With a valve that is too small in size, pressure in the assembly with the fluid circuit may possibly rise too high if the expansion of the fluid in the assembly with the fluid circuit is faster due to rapid heating than the amount of fluid that can be discharged from the fluid via the valve. assembly with the liquid circuit to the reservoir or expansion vessel of the expansion device. In both cases the pressure in the assembly with the liquid circuit will not run smoothly, and undesired defects may arise as a result of extreme pressure peaks.

4

In practice, both the pump and the valve in the connecting line between the assembly with the liquid circuit and the expansion device are often dimensioned too large to subsequently be adapted to the specific circumstances by additional measures. Such a measure may consist of a soft start control for a pump, with which the pump motor is slowly brought up to speed, or a load-dependent speed control, for example by means of a frequency converter. Connected in series with the valve, a manually operated second valve with throttling function can be provided in order to achieve a desirable fluid velocity.

Another problem of known heating systems of completely different order concerns the commissioning of an expansion device of this type, with pump and valve. If the pump still contains air, it may malfunction or not work. The hydraulic properties of a pump only come into its own when the pump is completely filled with liquid and contains no air or gas.

The present invention relates to a solution with which the ideal effective liquid flow can always be found in the assembly in a simple manner, both during the pumping action or the intake action via the valve, and with which, moreover, the pump can be automatically vented in certain preferred embodiments.

By placing a valve with variable opening between the assembly with the liquid circuit and the valve, with optionally a second connection to the suction side of the pump, preferably between a check valve and the pump, it has become possible to control the flow of liquid in both control directions with a standard pump without speed control and a standard valve without an additional valve with throttle function. With the invention it has become possible to automatically tune to any hydraulic situation (pressure and volume) with a standard pump unit (pump with valve).

Preferred embodiments of the invention are defined in the dependent claims.

In clarification of the invention, some embodiments of the invention are described in more detail below by way of example, and not limiting the invention, with reference to the appended drawing, in which the same or similar parts, components and aspects are indicated by the same reference numbers, and in which:

Figure 1 shows a heating installation 24 with an expansion provision 1, in an embodiment according to the invention; Figure 2 shows a heating installation 24 with conventional expansion provision 2;

Figure 3 shows an example for a circuit of variable-flow valve 24, in an embodiment according to the invention; Figure 4 shows a detail of an alternative embodiment with respect to that of Figure 1;

Figure 5 shows an additional embodiment with respect to that in Figure 4;

Figure 6 shows an alternative embodiment with respect to Figure 1;

Figures 7 and 8 show operating states in separate operating situations of the expansion device in the heating system according to the invention;

Figure 9 shows an additional alternative embodiment 30 with some similarity to that of Figure 6;

Figure 10; and

Figure 11.

6

Figure 1 shows how in the case of expansion device 1 according to the invention automatic pressure regulation takes place in a hydraulic-mechanical manner. A pressure sensor 11 transmits the system pressure in the assembly with the liquid circuit 25 to a usually electronically controlled (not shown) control unit, with which expansion device 1 is controlled. Due to temperature variations in the assembly with the liquid circuit 25, the volume of the liquid present therein is subject to change. An increase in the volume of liquid will increase the pressure in the assembly with the liquid circuit 25, and the reverse takes place with a decrease in the volume of liquid. By means of an interaction of the pump 4 with a valve 24 with variable passage, in particular controllable valve 5 in combination with valve 24, the liquid volume in the liquid circuit 25, consequently the system pressure therein, can be virtually, at least within a predetermined certain bandwidth.

Figure 3 shows how the pressure control is regulated globally. The cycle time T is shown on the x-axis of Figure 3, and the system pressure P on the y-axis. On the horizontal line indicated by S, the ideal system pressure is shown. Parallel to this line, the first adjacent are the lines on which the variable-passage valve 24 is activated. The outer lines shown in parallel relate to the extreme limits (upper and lower) for the installation pressure in the assembly with the liquid circuit 25, which is still permissible with respect to the ideal pressure according to line S in the graph of figure 3. We follow the dotted lines wavy line, which is symbolic for an imaginary system pressure reading from the pressure sensor 11, from the left to the top, then we see how 7, when passing the first parallel line valve 24 with variable passage is activated in the 'closed' position. As soon as the system pressure has reached the extreme (upper) limit value for the installation pressure in the liquid circuit 25, valve 5 is opened and simultaneously with this variable valve 24 is activated to the 'open' position (from the closed position). The variable passage of valve 24 will always swing in a delayed way from the closed position to the open position, and vice versa. This delaying effect (slow commuting between closed and open) is, in addition to the possibility of retaining any intermediate position, especially used according to the present invention. A period of time between the open and closed position of the variable passage of valve 24 can be as much as about 10 seconds or more, but also a shorter period of time does not have to be objectionable. In the case of a valve operating faster, the movement of the drive can after all always be interrupted.

The embodiment according to Figure 1 is based on 20 electrically controlled valves 5, 24, but pneumatic or hydraulic drives could also be chosen.

In figure 1 it is then easy to determine how the liquid flow from the assembly with the liquid circuit 25 will slowly start in the direction of the reservoir 3 of the expansion device 1 forming an expansion vessel, as the variable opening valve 24 slowly or at least gradually being opened further. As soon as a desired pressure drop of the system pressure in the assembly with the liquid circuit 25 is achieved (or rather, the desired system pressure), the variable opening of valve 24 remains in the position reached. Valve 5 closes the moment that the ideal system pressure in the 8 liquid circuit 25 is reached. The variable opening of valve 24 is (further) activated to the 'open' position as soon as the first parallel line below the ideal pressure line is reached. When the extreme (lower) limit value for the system pressure in the assembly with the liquid circuit 24 is reached, the pump 4 is activated. The valve 24 is also activated, from the variable opening from fully open to the position closed.

Figure 1 then shows how the liquid can be pumped around via the connecting pipes 6 and 7 and the assembly with the liquid circuit 25, without installation pressure changing. This is possible because the variable opening of valve 24 is still in the open position. With the reduction of the variable passage of valve 24, the desired pressure rise of the system pressure in the liquid circuit 25 is finally achieved, or if that occurs earlier, at the desired system pressure.

The variable opening of valve 24 remains in the achieved position.

As soon as the desired system pressure in the assembly with the fluid circuit 25 has been reached, the pump 4 stops and the variable passage of valve 24 closes completely.

During a process in which the temperature in the assembly with the fluid circuit varies 25, and consequently the fluid volume constantly changes, the system pressure will dynamically move between the extreme limit values as illustrated in Figure 3 and a switching pattern as described above. to repeat.

The importance of the invention according to figure 1 is best expressed by comparing it with figure 2, in which a liquid circuit 25 is shown with a conventional expansion device 2 without the new variable-pass valve 24.

A special feature of the expansion device 1 in figure 1 is that the reservoir 3 is designed without membrane 27, as is used in the known configuration according to figure 2. The special embodiment of expansion device 1 makes it possible to generate a lower atmospheric pressure at liquid levels in the lower part of reservoir 3, as a result of which degassing of the liquid can be effected very well.

At liquid levels in the upper part of reservoir 3, an above atmospheric pressure forms, whereby during the gases released below atmospheric, it can easily be discharged via an air vent 22. A consequence of this method is that the pressure can vary from below atmospheric pressure above atmospheric pressure. This makes static adjustment of pump 4 in a known configuration of Figure 2 particularly difficult, even if it were to be carried out, as in Figure 2, with soft start or variable speed control 20.

It becomes virtually impossible to provide an expansion device 2 with a reservoir 3 in order to control it under varying pressure conditions by means of only the valve 5 in combination with a manually operated valve 8 with throttling. Such a static adjustment is not suitable for a control in a dynamic hydraulic process, which can be achieved with a configuration, such as that shown in figure 1, with always variable pressure difference between the reservoir 3 and the assembly with the liquid circuit 25.

In the embodiment according to the invention, as it is shown in Figure 1, it is particularly simple to always optimally tune the fluid flows between the assembly with the fluid circuit 25 and the reservoir 3 of the expansion device 1, in response to the prevailing pressure in the reservoir 3 and the liquid circuit 25. This tuning is easy to control fully automatically by means of valve 24 with variable passage, in the embodiment according to figure 1, and the switching pattern as shown in figure 3.

As a possible embodiment of the valve 24 with variable opening, valve 24 can be designed with a position recognition, whereby it is possible to control the desired passage in a desired position (from the control unit) in advance. However, it is also possible to use a simple drive without position indication for valve 24 with variable passage. In this case, the control unit (not shown) measures the velocity or fluid flow, and adjusts the variable passage of valve 24 accordingly.

If a valve 5 with a larger capacity than required is used at pump 4, it is easily possible to operate a large operating range of smaller heating or cooling systems according to liquid circulation 25 with a standard version for liquid cycle 25 using the variable passage of valve 24 expansion device 1.

Another important advantage of the invention relates to the commissioning of the expansion device 1 according to figure 1. When an expansion device 1 is put into use for the first time, the assembly with the liquid circuit 25 and the expansion device will 1 - even after being completely filled with liquid - on vital parts such as a pump 4, may contain trapped amounts of gas, and therefore cannot function.

11

Only in an embodiment according to the invention, as shown in figure 1, can a pump 4 be vented and completely filled with water, without manual intervention being necessary. By keeping the valve 24 with variable passage 5 in a fully open position, one has to wait a short time for enclosed gases via the breather 19, for example a float breather associated with the pump 4, to subsequently start the pump 4. This pump 4 can now circulate water substantially without pressure difference via connecting lines 6 and 7 and the liquid circuit 25, until all enclosed gases have been removed. The pump 4, once filled with liquid, can fully function.

Such an action can be pre-programmed in the control unit, with which in the event of suspected air problems in the pump 4, this procedure can be repeated.

It is noted that the operation of the other components in figures 1 and 2 is clear to those skilled in the art, namely the sensor 10, the filter 13, the valves 12, 14, 15, 20 17 and non-return valve 18 and water pipe connection 16 for topping up the assembly via the expansion device 1, the water volume meter 9, etc., in particular in the connection shown and described.

In figure 1 a check valve 28 is further arranged between the variable passage valve 24, in particular (as is more clearly shown in figure 4) a motor valve 24, and pump 4. Although the intended effect of the motor valve remains the same, the check valve 28 serves to prevent water from flowing from the assembly 25 to the expansion tank 3, 30 through the pump 4 in the opposite direction, which is undesirable.

The embodiment of the expansion device 30 according to Fig. 4 is furthermore different from that of Figs. 1, 12 in that the non-return valve 28 with the entire connection between the motor valve 24 and the suction side of the pump 4 has been removed.

Many of the advantages envisaged by the invention can then still be achieved.

The embodiment of the expansion device 31 shown in Figure 5 differs from that of Figures 1 and 4 in that a pressure-controlled valve 29 is arranged, in particular parallel to the valve 24 with variable and preferably also adjustable passage and at the conventional valve 5 or valve for fluid intake from the assembly 25. As a result, an additional overpressure protection can be realized, wherein the pressure-controlled safety valve 29 is opened at a fixed, pre-set pressure value in the assembly 25 with the fluid circuit 25 for allowing liquid from the assembly to pass to the expansion device 31 and in particular the expansion vessel 3 (not shown in Figure 5).

If desired, in the embodiments of figures 4 and 5, a connection from the motor valve 24 to the suction side 20 of the pump 4 can also be provided, such as in the configuration according to figure 1.

The embodiment of Fig. 6 differs from the previous embodiments in that the pump 4 is included in a pump unit 32 including the motor valve 4, the non-return valves 12, 28, and the driven valve 5. In addition, a temperature sensor 33 is included in the same pump unit. By providing these elements in a common unit 32, a compact configuration of the entire expansion device 34 can be realized.

In addition, some adjustments have been introduced in the actual expansion tank 3.26. A measuring sensor 10 weighs the weight of the entire expansion tank 3. By determining the weight of the expansion tank in advance, ie without 13 filling with heat transfer fluid, the amount of water (fluid) in the expansion tank 3 can easily be traced on the basis of of weight change of the expansion vessel 3 with water therein. The degree of filling 5 can thus also be traced, in relation to the volume of the expansion vessel 3.

A further pressure sensor 35 is herein arranged, which measures the pressure in the gas part of the expansion vessel 3. Two valves are arranged in conjunction with the pressure sensor 35. These two valves 36, 37 serve for sucking in air or allowing air to escape from air, in conjunction with a pressure recorded by the pressure sensor 35. The operation is as follows.

In the gas-side part of the expansion vessel, air 15 can be sucked in via valve 36 in the event of a pressure drop in the expansion vessel of, for example, 0.3 bar. On the other hand, an excess of gas in the expansion tank 3 can lead to the opening of the second valve 37 to allow this excess to escape. Such a higher pressure in the gas in the expansion vessel is, for example, the result of an increase in the expansion liquid in the expansion vessel 3. Thus, air or gas can be vented to atmospheric pressure. A working pressure in the expansion vessel 3 is here between -0.3 and 0 bar 25 with respect to the atmospheric pressure. Thus, a significant improvement can be provided for degassing heat transfer fluid. Namely, an additional manner can be provided for degassing the heat transfer fluid in the expansion tank 3 relative to the option already provided with the float valve 22.

The embodiment 40 of Fig. 9 is very similar to the embodiment of Fig. 6, but 14 differs therefrom with regard to the following aspects and properties.

With regard to the expansion vessel 3, 26, some adjustments have been introduced. A pressure sensor 41 measures the pressure in the water section in the expansion tank 3.26 from a lowest point.

A second pressure sensor 38 measures the pressure in a liquid column 39, the end of which extends into the center of the expansion vessel 3, 26, because water enters from the liquid circuit 25 via the liquid column 39 into the expansion vessel 3, 26 with every intake column 39 remains almost completely filled with water. The liquid level or volume of the water in the water section in the expansion vessel 3, 26 will always vary in response to the temperature in the liquid circuit 25.

Because of the pressure variations of the gas pressure in the expansion tank 3, 26 described below, it is virtually impossible to determine the liquid level or volume with a simple pressure sensor. By now applying the two pressure sensors 41, 38, it is possible to determine an occurring difference in height.

After all, by calculating the pressure difference between the pressure sensors 41, 38, the liquid level in the lower half can be determined, whereby the variable gas pressure is eliminated.

When the two pressure sensors 41, 38 register a pressure equal to each other, the liquid level is equal to the outflow end of liquid column 39, halfway up the expansion vessel 3.26. The liquid level or volume in the upper half of the expansion vessel 3, 26 can then be deduced from measurement history values with respect to the lower half, and relates to the liquid column 39 increased by the gas pressure.

15

It is noted that in an embodiment not shown, the liquid column can still be provided with measures to further promote degassing, such as swirl generating means to further promote the release of gases from the liquid. For example, such swirl generating means may be formed by ratchet rings in the liquid column 39.

Typical for the measured pressure values in the upper part of the expansion vessel 3.26 is that the pressures of both pressure sensors 41, 38 will always be equal to each other, because the same liquid column with gas pressure applies.

In the embodiment of Fig. 9, the two valves 36, 37 are now again arranged with which the gas pressure in the expansion tank 3, 26 can be manipulated in this embodiment.

Valve 36, with which air can be drawn in, is in this embodiment a spring-loaded valve, which opens in one direction at a pressure difference of preferably 0.3 bar, and remains closed in the opposite direction. Valve 37, through which air can escape, opens in one direction with virtually no pressure difference, and remains closed in the opposite direction.

If now the liquid volume in the expansion vessel 3, 26 decreases, the gas volume will increase. However, since air can only enter via valve 36, the gas pressure in the expansion tank 3, 26 drops to a pressure of, for example, 0.3 bar below atmospheric pressure.

On the other hand, an excess of gas in the expansion tank 3, 26 can lead to the opening of the second valve 37 in order to allow this excess to escape. The just above atmospheric pressure in the gas in the expansion vessel is, for example, the result of an increase in the expansion liquid in the expansion vessel 3, 26. Thus, air or gas which has separated from the water, and located in the water section of expansion vessel 3, 26, are vented at atmospheric pressure through vent or float valve 22.

In this embodiment too, a working pressure in the expansion vessel 3 is between -0.3 and 0 bar with respect to the atmospheric pressure, as it is maintained in expansion vessel 26 of Fig. 2. Thus, a considerable improvement can be provided for degassing of heat transfer fluid. Namely, an additional way can be provided for degassing the heat transfer fluid in the expansion tank 3 relative to the option already provided with the float valve 22. Namely, the valves 36, 37 can be used, in a mechanical manner, as a spring-loaded embodiment, also be controlled by a switching mechanism or control, in combination with the recorded pressure in the expansion tank 3.26. The same applies to the embodiment in Figure 6. However, in the embodiment of Figure 9 it is made possible to realize a fully self-learning configuration in connection with the control.

Figures 7 and 8 each show three states, which show how unique the positioning of the motor valve 24 in relation to the other components of the expansion device 1 is.

Because the pump 40 in the embodiment of Fig. 9, as can be seen in the left-hand representation of Fig. 7, can always start virtually without pressure difference, it has become very simple to expel any air inclusions in the pump. After all, the system pressure is present here on both the suction side and the discharge side of the pump, as a result of which the pump action generates sufficient propulsion after switching on, to discharge any air present in the pump housing via (float) air vent valve 19.

However, even without the (float) breather 19, the air present in the pump 40 is discharged, but then disappears into the system, to subsequently be removed via system breather (s), or will eventually be degassed as a result of the improved degassing measures according to the invention

In the left-hand representation of Fig. 7, high pressure is circulated in the system through the pump 4 and the motor valve 24, which is completely open.

In the middle representation of Fig. 7, the motor valve 24 gradually closes, which is indicated by arrow A. The motor valve 24 can be held in any position, depending on a desired circulation. In the rightmost representation of Fig. 7 it is clearly shown that the motor valve 24 is completely closed. It will thus be clear that the flow generated with the pump 4 is fed entirely to the assembly with the liquid circulation. It has thus been made clear how the pressure in the assembly with the fluid circulation can be increased by appropriately controlling the motor valve. Liquid, required to increase the pressure in the assembly 25, then comes entirely, at least in the rightmost representation of Fig. 7, from the expansion tank,

The opposite state is also possible, whereby the pressure in the assembly must be reduced, because the pressure in the assembly 25 has become too high, in connection with, for example, an increase in temperature when a burner or other heat source is put into operation. From the situation of the left-hand display in Fig. 8, the valve 24 is gradually opened from a completely closed state with the pump 4 out of service. The arrow B in the middle representation 18 of Fig. 8 indicates that the motor valve 24 opens, and again it is noted that any intermediate position can be retained for any desired flow. Subsequently, the sequence in Fig. 8 from left to right reaches a state in which the motor valve 24 is fully open, indicated by the continued arrow B. In such a state, maximum liquid is withdrawn from the assembly 25 and fed to the expansion vessel.

A special embodiment of the invention is shown in Figure 10. The incoming liquid flow into the expansion device from the installation is controlled by a water dynamo 42. Such a water dynamo 42 comprises a water motor, which drives a generator with which electric current can be generated. .

15 Just as with the engine valve, an ideal liquid flow can always be realized. In order to obtain a very low liquid flow, the generator is manipulated in such a way, for example by forcing a high flow rate, that the water motor rotates very heavily.

Conversely, the generator, hence the water motor, runs virtually without resistance when a largest flow of liquid is to be realized.

In this way the same advantages are obtained with regard to the automatic venting of the pump and the continuous generation of an ideal liquid flow.

An additional major advantage is that the power supply can be used, by being fed back to the network, or for charging a battery, with which the control system can be supplied with a number of basic functions such as valve control.

If the control system can have a self-generated operating voltage, this gives, in addition to an energy saving, also greater operational reliability, for example in the event of a power failure of the (public) network.

It goes without saying that such a water dynamo 42 5 can also be used for other situations. In fact, wherever there is a pressure difference, where a liquid flow is necessarily part of a process, energy can be gained in this way.

According to the invention, more energy will be supplied additionally to fill a system with liquid from an unpressurized expansion vessel, but a large part of the energy required for the overall control, such as keeping this system under pressure, refilling and degassing activities, can be with the energy generated by the water dynamo 42.

As with the invention shown in the embodiment according to Fig. 10, a water dynamo 42 is also included in Fig. 11. The functions and advantages of the water dynnamo 42 in Figure 11 are the same as those of Figure 10, with the difference that the water dynamo 42 is not connected to the inlet of the pump. The pump can therefore not be vented in the manner previously described.

Furthermore, in Fig. 11, a tube 43 is provided under the breather 22 (here implemented with backflow protection) 25 on the expansion tank, relating to an embodiment with a membrane.

In this way the highest point at which gases can be discharged from the liquid-containing part of the expansion vessel is lowered to the bottom of the tube 43.

As a result of this measure, a small amount of gas always remains in the liquid-containing part of the expansion vessel, which is desirable when determining a water level when two pressure sensors 38, 41 are used in an expansion vessel with membrane, as described above in coherence with the embodiment of figure 9.

Instead of coupling a water motor with a generator, a water motor can be manipulated by means of a braking device into variable fluid passage. The advantage of saving energy is not an issue here, but a lower cost price can be achieved in this simplified manner.

It will be clear that various alternative and additional embodiments will occur to those skilled in the art after taking note of the foregoing. All these alternative and additional embodiments, however, are within the scope of protection of the present invention, insofar as they do not differ in letter or spirit from the definitions of this scope of protection in the appended claims. Thus, it is possible that a valve other than a non-return valve 28 is used between the motor valve 24 and the pump 4, and even an open connection may suffice, albeit that an in itself undesirable situation may arise that liquid from the suction side could flow from the pump 4 to the motor valve 24. In a control (not shown), any operating state can be set, controlled or programmed. A control unit is therefore not further shown in detail, but the individual components will be under the control of such a control unit. It is possible, in particular, for the motor valve 24 to register a position with one or another sensor and to transmit it to the relevant control unit. Such a registered position of the motor valve 24 can be useful when it comes to registering operating conditions, checking afterwards, for example after a defect, and normal operating conditions. Moreover, such a registered position can be pre-set and utilized for a specific operating state if at least approximately such an operating state is detected. Fine-tuning with respect to such a recorded value can then easily take place, without an interactive process requiring several calculation strokes to arrive at a desired setting of the motor valve. This contributes to simplicity and therefore elegance of the control and the control and control of the engine valve 10 24.

1036252

Claims (8)

A heat transport system, such as a heating system, comprising: 5. an assembly of a cold or heat source and a pipe system with heat exchangers connected to the heat source, and - an expansion device connected to the assembly, wherein between the heating system and the expansion - a device with a variable opening is provided. 2. A heat transfer system according to claim 1, wherein the variable opening valve is included in a conduit along which heat transfer medium is fed from the heating system to the expansion device. A heat transfer system according to claim 1 or 2, wherein the expansion device comprises an expansion vessel with a pump connected thereto to selectively feed heat transfer fluid to the assembly during operation of the pump. The heat transfer system according to claim 3, wherein the variable opening valve (24) is connected to a suction side of the pump. 5. Heat transport system according to claim 4, wherein the variable-opening valve is connected to the suction side of the pump via a non-return valve. A heat transfer system according to at least claim 2, wherein a pressure-controlled valve is arranged parallel to the variable-opening valve as protection against overpressure in the assembly. A heat transfer system according to at least one of the preceding claims, wherein the variable passage valve comprises a motor valve. 1036252 Expansion device, as apparently intended for a heat transfer system according to at least one of the preceding claims. 1036252