Patent Application
20180283559
The invention relates to a method for switching over a switching device between two switch positions in a hydraulic system, which apart from the switching device comprises a pump assembly. The invention moreover relates to a corresponding hydraulic system which is suitable for carrying out this method.
The most varied of switching devices are used in hydraulic systems, in order for example to close flow paths or switch between different flow paths. Thus for example in hydraulic heating systems which are used for heating a building as well as for heating service water, it is known to apply a switching device in the form of a switch-over valve which selectively leads the heating medium flow through the building or a heat exchanger for heating the service water. As a rule, separate drives are necessary for such switching devices, which render the switching devices relatively complicated with regard to their construction, and expensive.
Moreover, switching devices such as relief valves which switch by way of a change of the pressure are known. Such switching devices however cannot be used for switching between two flow paths for example, since the flow could then only be led through the one flow path at a low pressure. Moreover, switch-over devices are known, which are actuated byway of a rotation direction reversal of a pump assembly. With these systems, it is disadvantageous that the efficiency of the pump assembly is not the same in both rotation directions, and that the valve needs to be arranged in the proximity of the impeller.
With regard to these problems, it is an object of the invention to provide a method for switching over a switching device in a hydraulic system, as well as a corresponding hydraulic system which permits a switching device to be switched between two switch positions at a high efficiency and in a simple manner.
The method according to the invention serves for switching a switching device between two switch positions, wherein the switching device is arranged in a hydraulic system which apart from the switching device, comprises a pump assembly. According to the invention, the pump assembly is utilized, to initiate the switching device into switching between the switch positions. A purely hydraulic coupling of the pump assembly to the switching device via the hydraulic system itself, which is to say via the fluid delivered in the hydraulic system, is preferably envisaged for this. This means that no separate control connections or signal connections are necessary between the pump assembly and the switching device. The switching device for example can comprise one or more movable switching elements which can be moved between different positions, in particular between at least two possible switch positions.
According to the invention, the pump assembly has at least two different operating conditions. For this, the pump assembly is preferably provided with a control device which can set these two operating conditions. The pump assembly can preferably be a circulation pump assembly with an electronically activated drive motor, in particular a drive motor which is activated via a frequency converter, wherein the control device activates the drive motor. As described, according to the invention, a switching of the switching device is initiated by the pump assembly via the hydraulic system itself. According to the invention, one thereby envisages the switch positions of the switching device being achieved in a manner dependent on the stay duration of the pump assembly in at least one of the two operating conditions. This for example means that the pump assembly, if it remains for a longer time interval in a second operating condition, switches into the one switch position, and if it remains in this second operating condition for a shorter time interval, it switches into the other switch condition which is to say the other switch position or remains in this switch position. A predefined time interval for the operation in the respective operating condition and which is necessary for switching over is preferably stored in the control device. This means that the one switch position is reached if the operational duration in the operation conditional is shorter than the time interval, and the other switch position is reached if the operational duration is longer than the time interval.
Particularly preferably, two different operating conditions are envisaged, wherein a first operating condition is that operating condition, in which the pump assembly is operated in normal operation of the hydraulic system. The pump assembly can then be brought into a second operating condition for switching over the switching device, wherein the switching device is switched over as desired in a manner dependent on the time interval, in which the pump assembly stays in the second operating condition. In particular, the method can be configured such that the switching device switches over given a certain stay duration, and does not switch over or switches over and switches back again into the first switch position, given another stay duration. A desired switch position of the switching device can therefore be achieved in a manner depending on the stay duration in the second operating condition.
According to a preferred embodiment of the method according to the invention, the switching device is self-holding in each of the two switch position, on operation of the pump assembly in a first operating condition. The switching device in the first operating condition is preferably held in the respective switch position by a hydraulic pressure produced by the pump assembly. The pump assembly is brought out of the first operating condition into the second operating condition for switching between the switch positions of the switching device, wherein the self-holding function is lifted in this second operating condition. In particular, this can be effected by way of reducing the hydraulic pressure in the system. The switching device is switched to and fro between the two switch positions in this second operating condition of the pump assembly. For holding a desired switch position, the pump assembly, exactly when the desired switch position is reached, is brought again into the first operating condition, in which the switch position is again automatically held, for example by way of the hydraulic pressure. This means that the pump assembly in one of the two possible switch positions of the switching device is brought again into the first operating condition, depending on how long the pump assembly is operated in the second operating condition, so that the switching device is switched precisely into this switch position and then held again.
Particularly preferably, the pump assembly in the first operating condition is operated at a higher speed than in the second operating condition. A greater hydraulic pressure is produced in the hydraulic system in the first operating condition than in the second operating condition by way of this. Further preferably, the speed in the first operating condition is larger than a defined limit speed and in the second operating condition is smaller than or equal to the limit speed. Alternatively, the pump assembly can be switched off, which is to say can be at a standstill, in the second operating condition. Such a limit speed can be stored in the control device. Thereby, the limit speed is selected such that the desired self-holding function is given above the limit speed, and this self-holding function is no longer given below or at the limit speed, in order to permit the switching of the switching device to and fro, which is to say a switching-over of the switching device.
Further, one preferably envisages the switch device being moved into a defined starting position and being held there, on operation of the pump assembly in the second operating condition and/or at standstill of the pump assembly. This can be effected by a restoring element such as a restoring spring.
The switching device preferably assumes each of the two switch positions at least once when the switching device switches to and fro between the two switch positions. Thus by way of switching the pump assembly over into the first operating condition, it is possible to select the desired of the two switch positions, depending on the point at time, at which the pump assembly is switched into the first operating condition. The time durations for the switching to and fro are preferably known by a control device, so that the point in time for switching over the pump assembly into the first operating condition can be exactly defined.
Particularly preferably, the switching of the switching device to and fro is effected with the help of energy which has been previously stored on operation of the pump assembly in the first operating condition in at least one energy store and/or in the hydraulic system itself and/or is released to the hydraulic system by the pump assembly in the second operating condition. One can therefore make do without a separate drive of the switching device for moving a switching element of the switching device. Instead, the movement is preferably initiated by the hydraulic energy from the hydraulic system itself. Particularly preferably, the switching energy which is required for this is stored during the first operating condition and then utilized in the second operating condition of the pump assembly, in order to effect the switching-over which is to say the to and fro movement.
An energy store for example can be configured as spring storage means. Energy can be stored in the hydraulic system itself, for example as flow energy of the fluid flowing in the system. The fluid with its movement has a certain inertia and thus on switching over into the second operating condition of the pump assembly still has a certain energy, which it has absorbed in the first operating condition. In particular, the pressure in the system reduces more quickly than the flow energy given a reduction of the speed. Therefore, if the pressure is utilized for holding the switching device in a certain switch position, then this pressure can be very rapidly reduced for lifting the holding function, whilst sufficient flow energy is still present in the system, in order to be able to effect the switching-over of the switching device.
According to a further preferred embodiment, a movement between the two switch positions of the switching device or of a switching element of the switching device with the to and fro switching is delayed via at least one damping element and/or a path distance to be covered. This permits the switching to and fro to be delayed in a manner such that sufficient time remains, precisely in a certain switch position, which is to say at a defined point in time, to bring the pump assembly into the first operating condition, in order to hold the switching device in the desired switch position.
According to a preferred embodiment of the invention, the switching device comprises at least one damping device which is configured and acts in a manner such that it damps a direct impact of the switching device on reaching at least one of the two switch positions, i.e. damps the impact. In particular, the damping device preferably acts such that it permits a certain movement of the switching device beyond the reaching of the switch position. A direct rebounding or bouncing back from the reached switch position is prevented by way of this. In particular, such a damping device is useful if the switching device is moved solely by the inertia force of the fluid which flows in the system. With such a design of the switching device, the switching device preferably comprises two coupled valve elements which are freely movable together. One can prevent the valve element from hitting the valve seat and rebounding from this again by way of the damping device. The damping element can be configured as an elastically deformable element, for example as an elastic bellows or as an elastic valve seat. According to a preferred embodiment, it can be configured as a bellows, whose inner volume is open to the outside via a throttle location. An additional damping can therefore be achieved via the throttle. Alternatively or additionally, the damping element can be configured as a hydraulic damping element, for example by way of a piston moving in a cylinder, so that a volume in the cylinder is reduced and a liquid which is located in the volume is displaced through a throttle out of the volume. Therein, the throttle in particular can be formed by a gap between the piston and the surrounding cylinder wall. Herein, the piston can further preferably be formed by the valve element itself. Further preferably, the valve element can be configured such that with regard to its movement direction, it seals radially close to a sealing end position and comes to axially bear on a valve seat given a further movement.
The switching device can preferably comprise at least one linearly movable valve body or a linearly movable valve element, said body or element in a switch position sealingly bearing on an associated valve seat and being configured in a manner such that the valve body, with its movement, passes an annular wall which surrounds the outer periphery of the valve body and reduces the flow cross section, before reaching the valve seat. The annular wall herein extends parallel to the movement axis of the valve body. The annular wall forms a cross-sectional reduction of the flow path which is essentially closed by the passing valve body. The valve body can therefore in particular seal radially against the annular wall. The valve body can close the flow path through the valve seat before it comes to axially bear on the valve seat. The preferably cylindrical annular wall thereby comprises a cross section which is preferably slightly larger than the cross section of the valve body transverse to its movement direction.
The valve element or the valve body can therefore immerse for example into a surrounding cylinder and thus close the flow path through the cylinder whilst it can still move further by a certain amount in the direction of the longitudinal axis of the cylinder, before it axially abuts a valve seat. The switch position, in which the flow path is closed, is therefore reached before the movement of the valve element is stopped. This means that the impact is damped.
The described damping device has the effect that there is not only a short closure moment with the striking of the valve element or valve body on the valve seat, but that there is a longer closure time interval, in which the closure of the flow path is essentially given. The pump assembly can then be switched again into its first operating condition within this closure time interval. This means that a larger time window for the switching-over of the operating condition of the pump assembly for holding the switch position of the switching device is created by the damping device.
In the case that two coupled valve elements are provided, both valve elements can be coupled to corresponding damping devices. However, it is also possible to provide only one damping device which damps the impact of only one of the valve elements on its valve seat.
In a further preferred development of the method, the switching device is a switch-over device which switches between two flow paths for a flow produced by the pump assembly, wherein preferably a hydraulic pressure produced by the pump assembly in the just closed flow path is utilized to hold the switching device in its assumed switch position, as long as the pump assembly is operated in its first operating condition. For this, the switching device is preferably configured such that its switching element must be moved against the mentioned hydraulic pressure for opening the flow path. A self-holding function is thus created.
The subject-matter of the invention, apart from the previously described method, is a hydraulic system with at least one pump assembly and with a switching device having at least two different switch positions. I.e. at least one movable switching element of the switching device has at least two switch positions. The pump assembly simultaneously has at least two different operating conditions and the switching device is connected to the pump assembly via a hydraulic connection, preferably exclusively via a hydraulic connection. This is preferably that hydraulic connection, through which a fluid is delivered by the pump assembly. According to the invention, the switching device is moreover configured such that the switch positions of the switching device or of its switching elements can be reached in a manner depending on the stay duration of the pump assembly in at least one of the two operating conditions. The above description of the method is referred to concerning the manner of functioning. The hydraulic system according to the invention serves for implementing the method. It is to be understood that device features resulting from the preceding description of the method are likewise preferred designs of the hydraulic system, and procedures of the method which are simultaneously described hereinafter by way of the hydraulic system can be preferred method steps of the method according to the invention.
Particularly preferably, the switching device or at least a switching element of the switching device has two switch positions and the switching device is configured in a manner such that the switching device is self-holding in each of the two switch positions, on operation of the pump assembly in a first operating condition. This means that no external drive is necessary for holding the switch positions. The holding of the switch positions, as described above, is preferably effected by the hydraulic pressure in the system. Further preferably, the pump assembly as well as the switching device are configured in a manner such that for switching between the switch positions, they interact in a manner such that in a second operating condition of the pump assembly, the switch device switches to and fro between the two switch positions, and for holding a desired switch position the pump assembly is brought into the first operating condition on reaching the desired switch position. This means that the self-holding function is lifted by way of operation of the pump assembly in the second operating condition. A to and fro movement of the switching device between the possible switch positions is simultaneously initiated, so that the self-holding function can be put in operation again by way of a targeted re-switching of the first operating condition at a certain point in time, at which the switching device or its switching element is situated in a desired switch position, so that the switching device again is then held in this switch position in a stable manner.
As described above, the pump assembly is preferably configured such that its drive motor can be set or closed-loop controlled in its speed. The pump assembly preferably comprises a suitably configured control device for this. The pump assembly is further preferably configured such that in the first operating condition, the pump assembly is operated at a speed above a limit speed and that in the second operating condition of the pump assembly is operated at a speed smaller or equal to the limit speed or is at a standstill. The respective limit speed can be stored in a control device which sets the speed of the pump assembly and also initiates the switching-over of the switching device. Thereby, the limit speed is selected such that below the limit speed, the hydraulic pressure is preferably so small, that the switching device is no longer automatically held by the hydraulic pressure.
According to a further preferred embodiment, the switching device is provided with a drive element which in the second operating condition of the pump assembly switches the switching device to and fro between the two switch positions. The switching to and fro between the switch positions means that each of the two switch positions is reached preferably at least once. This e.g. means that if the switching device is initially situated in a first switch position, the switching device switches at least once into the second switch position. Further preferably, it then yet switches from the second switch position at least once back into the first switch position. The pump assembly thus at the first or second switch position can be brought again into the first operating condition in a targeted manner, in order to then hold the switch position in the described manner. The drive element is preferably a drive element which is supplied with energy from the hydraulic system which is to say energy which is provided by the pump assembly.
According to a further preferred embodiment, the drive element is configured in a manner such that it is movable by a force which is caused by a hydraulic flow, in particular by a hydraulic inertia force in the hydraulic system and/or comprises an energy store which is configured in a manner such that it stores energy or switching energy from the hydraulic system on operation of the pump assembly in the first operating condition, and releases this energy or switching energy on operation of the pump assembly in the second operating condition, by way of which energy the switching device is moved. The fluid flowing in the flow path has a kinetic energy which it still yet retains for a certain while even on switching off the pump assembly or with a reduction of the speed of the pump assembly. This energy can be utilized as switching energy, in order to move the switching device or the switching element of the switching device to and fro in the described manner. This is particularly possible, since the pressure in the system reduces more quickly than the kinetic energy of the fluid, on reducing the speed of the pump assembly. The self-holding function of the switching device can thus be lifted very quickly by way of reducing the pressure, whilst sufficient energy is still present in the system due to the inertia of the flowing fluid, in order to switch over the switching device. The drive element can be configured in the form of impact surfaces or catches, upon which the flow acts.
Alternatively or additionally, the switching device can be provided with an additional energy store, for example a spring storage means, a magnetic and/or pneumatic energy store. Such an energy store can be subjected to pressure in the first operating condition, and absorb energy from the hydraulic system, which energy it then releases again in the second operating condition, in order to switch the switching device to and fro in the described manner.
As described above, the switching device is preferably configured in a manner such that it switches at least once into each of the two switch positions, on operation of the pump assembly in the second operating condition.
According to a further preferred embodiment, the switching device can comprise a restoring element, for example a restoring spring, which is configured in a manner such that the switching of the switching device to and fro ends in a defined starting position of the switching device, and holds the switching device in this defined starting position given a standstill of the pump assembly. It can be ensured that the switching device is always situated in a defined switching position on starting operation of the pump assembly, by way of this.
The hydraulic system preferably comprises a control device, in particular an electronic control device, which is configured in a manner such that it firstly brings the pump assembly out of the first operating condition into the second operating condition on the basis of a switching command for switching over the switching device from the first into the second switching position, and brings the pump assembly back again into the first operating condition after a defined time interval which is matched to the time duration of the to and fro movement of the switching device in a manner such that the switching device is situated in the second switch position when the pump assembly is brought again into the first operating condition. Thus a switch-over into the second switch position condition is therefore rendered possible, departing from the first switch position. The control device is particularly preferably integrated into the control and/or regulation electronics of the pump assembly which are present in any case. Thus the electronics for the control or regulation of the pump assembly and which are present in any case can be used, in order to switch the switching device from a first switch condition into a second switch condition.
The hydraulic system is preferably configured such that the pump assembly comprises a speed controller for changing the speed of the pump assembly, wherein the speed controller preferably comprises a braking circuit which actively brakes the pump assembly with a reduction of the speed. Such a speed controller can be integrated into the control device of the hydraulic system or of the pump assembly and can preferably comprise a frequency converter. Such a braking circuit means that given a reduction of the speed, the pump assembly not only runs out, but is also actively braked by way of a suitable subjection of the coils of the electric drive motor to current. This is particularly advantageous if the energy for the operation of the drive element is to be taken from the hydraulic flow in the system. The hydraulic pressure is reduced rapidly due to a particularly rapid reduction of the speed which such a braking circuit renders possible, whereas the flow is still retained for a short time due to the mass inertia of the fluid. Thus the energy of this flow can be utilized, in order to move the drive element, whilst a hydraulic pressure which can be used to hold the switching device in the desired switch position has already fallen away.
The hydraulic system according to the invention and the method according to the invention can be applied for the most varied of application purposes. A switching device for example can serve for switching over between two flow paths in a hydraulic system, for example in systems, which distribute fluids to different tapping locations, cleaning systems, spring wells with different exit nozzles which are not operated at the same time, and in particular in heating installations. Thus in compact heating installations, it is common to provide two circuits, a heating circuit which runs through the radiators of the building, and a circuit which runs through a heat exchanger for heating service water. One can switch between these heating circuits with the help of a switching valve, which is to say a switching device. The system according to the invention and the method according to the invention permit the switch-over by way of a special operation of the pump assembly in this system, so that one can make do without a separate drive motor for a switch-over valve.
If the energy for driving a drive element of the switching device is to be taken from the hydraulic system, be it that the energy is stored in a separate energy store or however the energy is provided in the form of kinetic energy of the flow fluid, it is advantageous for the switching device in a first switch position, which corresponds to the idle position on starting operation of the system, to be situated in a position, in which the circuit through the heat exchanger for heating the service water is open and the heating circuit is closed. This is advantageous since the circuit through the heat exchanger is a defined and known circuit which as a rule is always situated in an unchanged hydraulic condition. This circuit as a rule is formed in a boiler itself and is known on the part of the manufacturer. The heating circuit through the building in contrast is not known with regard to its exact formation and comprises a multitude of valves, whose valve positions are not known, so that the flow through this circuit is also not known. If the circuit through the heat exchanger is opened in the first switch position, it is thus ensured that adequate energy is always present in the system in this first switch position, in order to be able to drive the drive element for switching into the second switch position.
If the switching device is automatically held in one of its switch positions by the hydraulic pressure in the system, then the occurring holding force can be adapted by way of adapting the size of the pressure surface, upon which the hydraulic pressure acts. In this case too, the drive element can be moved by the hydraulic flow in the system, and impact or pressure surfaces of the drive element adapted with regard to their size, in order to change the occurring forces for moving the switching device. The switching device can therefore be adapted to a special hydraulic system, by way of the surfaces, upon which hydraulic pressures or flows act, being dimensioned such that the desired force conditions are produced for holding and/or moving the switching device.
Further preferably, the switching device is integrated together with a pump assembly into a hydraulic block or hydroblock for a heating facility. Such hydraulic blocks form integrated hydraulic construction units for heating facilities which comprise at least a part of the internal flow paths of the heating facility and apart from a pump assembly, which is to say preferably a circulation pump assembly, comprise further hydraulic components, thus preferably the switching device according to the invention. The switching device is integrated with the pump assembly into a common construction unit which in particular also comprises the necessary flow paths between the switching device and the pump assembly. Furthermore, further components, such as for example sensors or a venting device can be integrated into this hydraulic block. The hydraulic block preferably comprises conduit connections which are provided for connection to further components of a heating facility. Thus preferably, a first conduit connection is provided for connection to a primary heat exchanger of the heating facility. Further preferably, a second conduit connection is provided for connection to a heating circuit through a building. Furthermore, a conduit connection for connecting to a secondary heat exchanger for service water heating can preferably be provided on the hydraulic block. Particularly preferably, the connection for connecting to the primary heat exchanger is connected in the inside of the hydraulic block to the delivery side of the pump assembly, whilst the connection for the secondary heat exchanger and the connection for the heating circuit are each connected to an inlet of the switching device in the inside of the hydraulic block. The switching device therein preferably forms a switch-over valve between a hydraulic circuit through the secondary heat exchanger and a hydraulic circuit through the heating circuit.
The invention is hereinafter described by way of example and by way of the attached figures. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
In the drawings:
Referring to the drawings, the invention is hereinafter described by way of example and by way of a hydraulic system which represents a heating system. However, it is to be understood that the invention can also be applied in other hydraulic systems, in particular in hydraulic systems, in which a switching between two flow paths is necessary. This particularly applies to a circulation system but is expressly not limited to such.
A branching point or node point 14, at which the flow path branches, connects downstream of the primary heat exchanger 12. A first branch of the hydraulic system, departing from the node point 14, runs through a secondary heat exchanger 16, in which for example service water to be heated is heated. This branch of the hydraulic circuit, at the exit side of the secondary heat exchanger 16, runs out into a first entry 18 of the switching device 4. A second branch which extends in a manner departing from the node point 14 forms a heating circuit which for example serves for heating a building. This heating circuit here is represented schematically by a radiator 20 with a regulation valve 22 which is arranged on this. The regulation (control) valve 22 can for example be a common thermostat valve. This heating circuit at the exit side runs out into a second entry 24 of the switching device 4. It is to be understood that indeed such a heating circuit can comprise more than one radiator 20 which are connected in parallel and/or in series. In this example, the heating circuit yet comprises a bypass 26 which serves for permitting a flow through the heating circuit when the regulation valve 22 or all regulation valves 22 in the heating circuit are closed.
What is essential to the invention is the special design of the switching device 4 which is configured such that one can make do without a separate drive for the switching device 4 and in contrast this can be switched over solely via the circulation pump 2 by way of changing the operating condition of the pump assembly 2. This is effected by a control device 28 of the pump assembly 2. In this example, the control device 28 is integrated directly into the pump assembly 2, for example directly on or in the motor casing of the pump assembly 2. With regard to the pump assembly 2, it is preferably the case of a circulation pump assembly which can be closed-loop controlled in its speed and is activated via a frequency converter. This in particular is configured as a centrifugal pump assembly, preferably with a wet-running electric motor.
The switching device 4 serves for switching between the two described flow paths, which is to say on the one hand through the secondary heat exchanger 16 and on the other hand through the radiators 20 of the heating circuit. For this, the switching device comprises two valve seats 30 and 32, to which in each case a valve element 34 and 36 respectively (switching element 34 and 36) is assigned. The valve elements 34, 36 are connected to one another in a fixed manner and are arranged such that they can be alternately brought into sealing contact with the respective associated valve seat 30, 32. This means that when the valve element 36 sealingly bears on the valve seat 32, as in the condition represented in
Moreover, an elastic bellows 40 whose closed interior is in connection with the connection space 38 via a through-hole 42 in the valve element 36, is arranged on the valve element 36, away from the valve seat 32. The through-hole 42 is configured as a throttle location. A spring 44 which is configured as a tension spring engages on the end of the bellows 40 which is away from the valve element 36, and the spring at its other end is fastened on the housing 46 of the switching device 4.
The pump assembly 2 is brought into a second operating condition by way of the control device 28, in which second operating condition the speed lies below the predefined limit speed, in order to move the valve or the switching device 4 into its second switch position, in which the valve seat 30 is closed and the second valve seat 32 is opened. In this condition, the pressure at the second entry 24 drops to such an extent that the force which is directed by the pressure on the bellows 40 toward the valve seat 32 is smaller than the tension force exerted by the spring 44. This leads to the spring 44 contracting as is shown in
As described, the selection of the new switch position depends on the point in time, at which the pump assembly 2 is brought again into the first operating condition, which is to say that the selection of the switch position depends on how long the pump assembly 2 is operated in the second operating condition. If the pump assembly 2 is not switched again into the first operating condition 1 at the correct time, then the switching device 4 switches back into the first switch position by way of the return displacement of the valve elements 34 and 36. The switching device 4 is again operated in the first switch position, when the pump assembly 2 is again brought into the first operating condition.
Moreover, the described switching-over is likewise effected without an external drive, but solely via a hydraulic coupling of the pump assembly 2 to the switching device 4 via the hydraulic system itself. The spring 44 serves as an energy store which receives energy on operating in the first operating condition and then releases it again due to relaxation on switching into the second operating condition. Thus a force for moving the valve element is produced by the spring 44. The energy or switching energy which is required for this is previously taken by the spring 44 from the hydraulic system in the first operating condition.
The bellows 40 with the through-hole 42 which acts as a throttle serves for decoupling the spring 44 from the valve elements 34 and 36 during the charging procedure, with which the spring 44 absorbs energy. The bellows 40 thus specifically permits the spring 44 to be extended in a first operating condition, without having to move the valve elements 34 and 36. The valve elements 34 and 36 in contrast remain in the starting position shown in
What is essential to the system is the fact that the two operating conditions merely necessitate different speeds and thus different starting pressures of the circulation pump assembly 2, but not a rotation direction reversal of the pump assembly 2. This benefits the efficiency. Moreover, it is not necessary to completely switch off the pump assembly 2 for switching the two operating conditions However, it is also possible for the second operating condition to not only have a reduced speed, but for the pump assembly 2 to be completely stopped in the second operating condition. Even then, it only needs to be started in operation again sufficiently rapidly, in order to prevent a return movement of the valve elements 34 due to the expansion of the bellows 40 or, as the case may be, an additional spring. This means that the selection of the switch position is dependent on how long the pump assembly 2 is operated in the second operating condition.
The switching device 4 which is described here, as also the subsequently described embodiment examples of switching devices are envisaged to be arranged at the suction side of the pump assembly 2 in the described manner. However, it is to be understood that a suitably configured switching device can also be applied at the delivery side of the pump assembly 2. With the switching device represented in
Different embodiment examples of switching devices are now described hereinafter, and these can all be integrated in to a hydraulic system such as the shown heating system, in the manner described by way of
The subsequently described embodiment examples according to
The switching device 4 which is represented in
A bellows 40 bears on the valve element 34, as is described by way of
A through-hole 42′ is formed in the connection element 37 and this, as is the case with the through-hole 42, acts as a throttle and connects the interior of the bellows 40 to the interior of the second bellows 58, said second bellows being arranged on the valve element 34 at its side which is away from the valve seat 30. Thus a closed system which can be filled with a fluid, in particular water, is therefore created in the inside of the bellows 40 and 58. No fluid exchange thereby occurs with the surrounding fluid in the hydraulic system, so that a contamination of the throttle location formed by the through-hole 42 can be prevented.
If the pump assembly 2 is now switched by its control device 28 into the second operating condition with a lower speed, then the pressure acting upon the disc 56 reduces so that the force acting upon the disc 56 in the axial direction X is no longer in equilibrium with the spring force of the extended first section of the spring 44′. This first section of the spring thus pulls the disc 56 away from the valve seat 32. Since the bellows 40 is not filled again straightaway due to the throttle effect of the through-hole 42, the compressed bellows thereby together with the valve element 36 is moved away from the valve seat 32 and the valve is thus opened. The valve element 34 simultaneously comes into sealed contact on the valve seat 30. If the pump assembly 2 is now set into the first operational condition with a higher speed before the bellows 40 unfolds again, the greater pressure then acts at the first closure 18 and thus produces a force which acts towards the valve seat 30 in the axial direction X, upon the face side of the bellows 58 and thus upon the valve element 34. This force holds the valve element 34 with a sealed contact on the valve seat 30. Thus, a self-holding condition of the valve is achieved on operation of the hydraulic system. The second bellows 58 now empties via the through-hole 42′ due to the pressure force, so that the first bellows 40 is expanded again and reaches the condition which is represented in
The embodiment example in
In contrast to the embodiment described by way of
The embodiment which is shown in
If now the pump assembly is switched into the second operating condition with a lower speed, then the pressure force upon the disc 56 reduces, so that the spring force which is produced by the tensioned tension spring 60 exceeds this pressure force. The switching energy which is stored in the tension spring 60 thus discharges and the tension spring 60 pulls the disc 56 towards the closure 52 in the axial direction. Thereby, since the disc 56 bears on the contact shoulders 78 of the detent hooks 76, the valve element 36 connected to the detent hooks 76 is co-moved and is lifted from the valve seat 32 in the axial direction X. The other valve element 34 is co-moved via the connection element 37 and is brought to bear on the valve seat 30 as is shown in
With the embodiment example according to
The subsequently described embodiment examples according to
Again, a self-holding condition is achieved, which continues to be held when the pump assembly is then again brought into its first operating condition. If this is not effected, then the arrangement of the two valve elements 34 and 36 can move again back into the first switch position, in particular also due to the effect of the spring 82. This means that here too, it is a question of when the pump assembly 2 is switched again into the first operating condition. Thus a switch-over of the flow path between the entries 18 and 24 is hereby also possible without an additional drive, wherein energy which was previously stored in the system is utilized for moving the valve elements 34 and 36. A bellows (bag) 86 which connects the valve element 36 to the connection element 37 is additionally provided in this system. The bellows 86 serves as a damper and prevents the valve element 36 from moving back again straight away due to the impact energy, when it is pressed against the valve seat 32 by the flow. This impact energy can be absorbed by way of the bellows 86 springing in. I.e., the valve element 34 and the connection element 37 can move yet further, whilst the valve element 36 already closes the valve seat 32. This condition is shown in
The embodiment example according to
The embodiment example according to
The pump assembly 2 is preferably configured as a pump assembly with an electric drive motor which is activated via a frequency converter. The use of such an activation has the advantage that the pump assembly 2 can be additionally braked by opposing magnetic fields on reducing the rotational speed. A more rapid speed reduction is therefore achieved. The applied bags or bellows 40, 58, 86, 88 and 92 are preferably manufactured of rubber or a suitable elastomer.
The shown hydraulic block as an essential component comprises a pump assembly 2. This pump assembly 2 comprises a motor housing 72 with the electrical drive motor 70 which is arranged therein as well as an electronics housing 74 which is attached at the axial side and in which the control device 28 is arranged. The pump casing 64 of the pump assembly 2 is an integral constituent of the hydraulic block 98 which furthermore comprises further hydraulic flow paths and components. In particular, a switching device 4 according to the invention is arranged in the inside of the hydraulic block 98. The switching device 4 here is configured as a switch-over device which switches over the hydraulic flow path between a secondary heat exchanger 16 and a heating circuit through the radiator 20, as has basically been described by way of
The hydraulic block 98 comprises a first inlet 18 or first connection 18 which here is formed for the direct connection to the secondary heat exchanger 16. The first inlet 18 bears on the rear side of the hydraulic block 98, whilst the pump assembly 2 is situated at the front side. The envisaged installation position of the hydraulic block 98 in a heating facility is thereby such that the rotation axis of the pump assembly 2 extends horizontally. The hydraulic block 98 further comprises a second inlet 24 which is configured for connection to a heating circuit through the radiator 20 (see preceding description). The second inlet 24 here is configured as a threaded connection which extends downwards in the envisaged installation position. This is preferred since the conduit connections for the external pipework are preferably directed downwards in the case of common hydraulic blocks for heating facilities, in particular compact heating facilities. The hydraulic block 98 moreover comprises a delivery-side connection 10 which is provided for connection to the aforementioned primary heat exchanger 12 and in the pump casing 64 is connected to the delivery side of the pump assembly 2. The hydraulic block 98 further comprises yet an end-vent receiver 100, in which an end-vent which is not shown is inserted. Furthermore, further opening as assembly openings and receivers are provided for sensors, such as for example the assembly opening 102 which permits an access to the switching device 4 for maintenance and assembly purposes. The openings 104 and 106 function for example as receivers for pressure and/or temperature sensors.
The switching device 4 in the embodiment according to
In this embodiment example, the housing 46 of the switching device 4 is likewise integrated into the hydraulic block 98 and in particular is configured as one piece with the pump casing 64 and the connecting flows paths to the inlets 18 and 24. A connection space 38 which is connected to the suction side or to a suction connection in the pump casing 64 and thus forms a suction-side flow path to the impeller 68 is situated in the housing 46. The connection of the connection space 38 into the pump casing 64 with regard to its function corresponds to the outlet 6 in the embodiment example according to
The manner of functioning of the switching device 4 in the embodiment according to
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 15188146.3 | Oct 2015 | EP | regional |
This application is a United States National Phase Application of International Application PCT/EP2016/073409, filed Sep. 30, 2016, and claims the benefit of priority under 35 U.S.C. § 119 of European Application 15 188 146.3, filed Oct. 2, 2015, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/073409 | 9/30/2016 | WO | 00 |
