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(11) | EP 4 198 404 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A LEAKAGE CONTROL SYSTEM FOR HEATING INSTALLATIONS |
| (57) The present invention relates to a leakage control system for alerting of leakages
in connection with refilling a secondary circuit of a central heating installation.
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Technical field of the invention
Background of the invention
[0002] Heating installations based on, for the consumer local, but central heat exchangers, boilers or the like require continuous monitoring so that the secondary side of the heating circuit does not achieve a too low operating pressure over time. Dropping operating pressures may be due to leakage or the like.
[0003] When a heating circuit is maintained by a wider group of employees, the person responsible for the heating circuit runs the risk of overlooking a leakage in the secondary heating circuit, as several employees, independent of each other, possibly fill the secondary heating circuit with medium. In addition, there is an inherent risk of error in carrying out the task, as the correct filling of medium depends on human interaction and interpretation of "correct" procedure. Thus, a human action is required to partly initiate and partly terminate the filling of medium into the secondary heating circuit.
[0004] Thus, the situation presents two primary challenges, both of which result from a secondary heating circuit with a too low operating pressure. In part, there is a challenge for connected operating equipment - for example circulation pump - as these are directly negatively affected by low operating pressure. In part, it is a challenge that the manual process, which should lead to remedying the low operating pressure, increases the risk of overlooking a leakage in the secondary heating circuit.
Object of the invention
[0005] The objective of the present invention is to achieve a continuous monitoring ensuring that the secondary side of the installation is continuously supplied with the required amount of medium so that the correct operating pressure is maintained.
Description of the invention
[0006] A first aspect of the present invention relates to a leakage control system for alerting of leakages in connection with refilling a secondary circuit of a central heating installation, wherein the secondary circuit of the central heating installation comprises:
- a filling pipe;
- a supply pipe;
- a return pipe; and
- a circulation pump, advantageously mounted in the supply pipe;
- a pressure transmitter operatively connected to the return pipe;
- a flow meter operatively connected to the filling pipe;
- a nonreturn valve or nonreturn control integrated in the filling pipe;
- optionally, a manually or electrically operated valve adapted for controlling the flow, such as opening or closing the flow, of medium via the filling pipe; and
- a control unit operatively connected to the pressure transmitter and the flow meter.
[0007] In one or more embodiments, the control unit is further configured to calculate the current operating pressure in the secondary circuit of the central heating installation based on input from the pressure transmitter. In one or more embodiments, the control unit is further configured to give an alarm if the current operating pressure is below a predefined minimum operating pressure.
[0008] In one or more embodiments, the control unit is further configured to receive flow signals from the flow meter. In one or more embodiments, based on the received flow signals from the flow meter, the control unit is further configured to determine and log the volume of medium that is refilled in the secondary circuit of the central heating installation via the filling pipe, for example in response to the above-mentioned alarm.
[0009] A second aspect of the present invention relates to a leakage control system for alerting of leakage in connection with refilling the secondary circuit of a central heating installation, wherein the secondary circuit of the central heating installation comprises:
- a filling pipe;
- a supply pipe;
- a return pipe; and
- a circulation pump, advantageously mounted in the supply pipe;
- a pressure transmitter operatively connected to the return pipe;
- a flow meter operatively connected to the filling pipe;
- a nonreturn valve or nonreturn control integrated in the filling pipe;
- optionally, a manually or electrically operated valve adapted for controlling the flow, such as opening or closing the flow, of medium via the filling pipe; and
- a control unit operatively connected to the pressure transmitter and the flow meter, wherein the control unit is further configured to calculate the current operating pressure in the secondary circuit of the central heating installation based on input from the pressure transmitter and give an alarm if the current operating pressure is below a predefined minimum operating pressure; and wherein the control unit is configured to receive flow signals from the flow meter and based thereon determine and log the volume of medium that is refilled in the secondary circuit of the central heating installation via the filling pipe, for example in response to the above-mentioned alarm.
[0010] In one or more embodiments, based on input from the pressure transmitter, the control unit is configured to calculate the supplied volume of medium that is required to increase the operating pressure in the secondary heating circuit to a given level.
[0011] In one or more embodiments, the control unit is further configured to give an alarm if the current operating pressure is above a predefined maximum operating pressure.
[0012] In one or more embodiments, the leakage control system further comprises an electric actuator operated valve adapted for controlling the flow, such as opening or closing the flow, of medium via the filling pipe.
[0013] In one or more embodiments, the control unit is further configured to, based on input from the pressure transmitter, via the electric actuator, open or close the valve.
[0014] In one or more embodiments, the control unit is configured for automatic filling of the secondary circuit of the central heating installation with medium via the valve if the current operating pressure is below a predefined minimum operating pressure.
[0015] In one or more embodiments, the control unit is configured to generate an alarm if the filled volume of medium exceeds the limit for a single filling.
[0017] In one or more embodiments, the electric actuator comprises a wireless communication device configured to wirelessly receive controlling signals for the electric actuator.
[0018] In one or more embodiments, based on input from the pressure transmitter, if the current operating pressure is below a predefined minimum operating pressure, the control unit is configured to stop the circulation pump, for example via a relay.
[0019] In one or more embodiments, the leakage control system can compare the measured operating pressure with preselected limits for minimum pressure, insufficient pressure, sufficient pressure, high pressure, and dangerous pressure, and arranges indicators on the front plate of the system and alarm response accordingly.
[0020] In one or more embodiments, the leakage control system can compare the filled volume with preselected limits for single fillings and total daily fillings and arranges indicators on the front plate of the system and alarm response accordingly.
[0021] In one or more embodiments, the leakage control system can compare the interval between fillings with a fixed minimum time and arranges indicators on the front plate of the system and alarm response accordingly.
[0022] In one or more embodiments, the leakage control system can be equipped with a shutoff valve in the feed pipe for refilling so that such a refilling can be initiated and terminated by means of this.
[0023] In one or more embodiments during refilling, the leakage control system can be requested to be initiated and terminated by pressing a key on the front plate of the system.
[0024] In one or more embodiments during refilling, the leakage control system can be requested to be initiated and terminated during remote control by issuing certain commands via a communication system.
[0025] In one or more embodiments during refilling, the leakage control system can be terminated automatically when the operating pressure has reached a sufficient value.
[0026] In one or more embodiments during refilling, the leakage control system can be initiated automatically when the operating pressure has dropped to an insufficient value. System as above characterized in that refillings can be rejected outside fixed periods of time and days of the week.
[0027] In one or more embodiments, the leakage control system will be configured to record pressure (p) for each refilling at the beginning and end of a filling and filled quantity or volume (v) and thereby calculate and record the characteristic elasticity (E) of the installation, which is logged for each filling. The characteristic elasticity of the installation can be calculated by the following formula, E=Δp/Δv, wherein delta p and delta v can be determined as the difference in pressure, respectively volume, from the beginning to the end of the filling.
Preferably, in one or more embodiments, before each filling, based on the recorded elasticity of the installation, the leakage control system will be configured to calculate the volume required to be supplied to bring the operating pressure from the current to a predefined desired value. Preferably, the leakage control system can also be configured to ensure that the supplied volume during filling does not exceed the thus calculated volume significantly og alarm in the case of significant excess.
[0028] In one or more embodiments, based on input from the pressure transmitter and the flow meter, preferably during a refill operation, the control unit is, configured to calculate and log the characteristic elasticity of the installation.
[0029] In one or more embodiment, based on the calculated characteristic elasticity, the control unit is configured to calculate a required amount of water for a future refilling.
[0030] In one or more embodiments, during a given refill operation, the control unit is configured to control that the filled amount of water recorded on the flow meter does not exceed the calculated amount of water for the mentioned future refilling with a predefined limit value.
[0031] In one or more embodiments, the control unit is configured to give an alarm if the mentioned calculated amount of water exceeds the mentioned predefined limit value.
[0032] The singular form used in the description and the claims also comprises the plural form unless the context clearly indicates otherwise. Intervals can be expressed here as from "around" or "approximately" a specific value and/or to "around" or "approximately" another specific value. When such an interval is indicated, another aspect comprises from the one specific value and/or to the second specific value. In the same way, it is understood that when values are indicated as approximations and are preceded by the word "around", the specific value constitutes yet another aspect.
[0033] It should be noted that aspects and functions described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.
Brief description of the figures
References
[0035]
- 1
- Leakage control system
- 2
- Control unit
- 3
- Supply pipe
- 4
- Return pipe
- 5
- Pressure transmitter
- 6
- Filling pipe
- 7
- Flow meter in filling pipe
- 8
- Shutoff valve in filling pipe
- 9
- Nonreturn valve
- 10
- Electric actuator
- 11
- Circulation pump
Detailed description of the invention
[0037] Figure 1 describes a system 1 according to one or more embodiments of the invention. In a purely manually operated system, the electric actuator 10 is constituted by a handle operatively connected to an actuator (manual actuator). The filling pipe 6 can either be connected to a district heating supply or to a water supply for domestic use, in which cases the nonreturn valve 9 can be in the form of a proper nonreturn control.
[0038] The control unit 2 is configured to receive flow signals from the flow meter 7 and - if the system is designed with automation - to provide a command signal for the shutoff valve 8. The control unit 2 is further configured to calculate the current operating pressure based on input from the pressure transmitter 5.
[0039] For flow measurement, for example, a static ultrasound meter with current pulse output is used. When using current pulses, it is ensured that consumption is recorded immediately after it has passed the meter 7.
[0040] For pressure monitoring, for example, a pressure transmitter 5 is used that allows measurement of the real current pressure at the time of measurement so that all calculations are made by the control unit 2.
[0041] For monitoring and intervention against low operating pressure, a number of predefined limit values are used that aim at remedying a low operating pressure concurrent with monitoring leakage indicating drops in operating pressure.
Monitoring of operating pressure
[0042] The leakage control 1 is based on measurement of the supplied volume that is required to increase the operating pressure in the secondary heating circuit to a given level.
[0043] The leakage control can operate in three ways:
- 1) Fully manual operation:
The leakage control 1 is not equipped with an independent shutoff valve. A local filling valve is operated manually after the leakage control indicates insufficient operating pressure as the leakage control measures the filled volume. If the time interval since the previous filling is shorter than a predefined time, a warning/alarm is given by the leakage control 1. The warning can be reset by pressing a key on the front of the leakage control.
The local valve is closed manually when the leakage control (for example via the control unit 2) indicates sufficient operating pressure. If the filled volume exceeds a predefined limit, the secondary heating circuit is considered to show a leakage, and the leakage control 1 gives an alarm. This can be reset by pressing a key on the front of the leakage control. If the local valve remains open and the pressure in the secondary heating circuit exceeds a critical predefined limit, an additional alarm is given. This alarm cannot be reset on the leakage control, but only by reducing the pressure in the secondary heating circuit when draining the medium.
- 2) Local operation of semiautomatic leakage control:
The leakage control 1 is equipped with an independent shutoff valve 8, but is not configured for automatic filling. The filling is initiated locally by operating the keyboard of the leakage control. If the conditions for filling are present (operating pressure insufficient, a suitable length of time has passed since the previous filling), the leakage control (for example via the control unit 2) will open the shutoff valve 8 og thereby initiate a filling as it still measures the filled volume by signal from the connected flow meter 7. Otherwise, the leakage control (for example via the control unit 2) will indicate errors (alarm). As sufficient operating pressure is achieved, the leakage control will stop the filling by closing the shutoff valve 8 again. Before that, the filling can be stopped manually by pressing the keyboard of the leakage control again.
- 3) Fully automatic filling:
The leakage control 1 is equipped with an independent shutoff valve 8 and configured for automatic filling. The filling starts when the operating pressure drops to the limit 'insufficient' (predefined) whereupon the leakage control (for example via the control unit 2) opens the shutoff valve 8, thereby initiating the filling as it measures the filled volume by signal from the connected flow meter 7.
The filling is normally interrupted when the operating pressure reaches the limit 'sufficient' (predefined) whereby the leakage control (for example via the control unit 2) closes the shutoff valve 8 again. The filling is interrupted by leakage alarm if the filled volume exceeds the limit for a single filling (predefined) or if the limit (predefined) for daily filled volume is reached. The filling does not start if the time interval since the previous filling is shorter than a predefined time; and in that case a leakage alarm is given instead.
Remote manual filling:
[0044] The leakage control 1 allows remote manually controllable filling by means of connecting to the suitable remote control system. The communication between the leakage control and the remote control system can, for example, be performed as an "always-on" wireless communication channel that ensures the possibility of continuous monitoring and "near real-time" remote control of the leakage control 1 regardless of the physical location of the operator. The combination of "always-on" and "near real-time" ensures that the operator can follow an ongoing filling continuously - regardless of whether it is manually or automatically initiated - just as it gives the operator the opportunity to stop a filing if the operator deems this necessary.
[0045] The communication between the leakage control 1 and the remote control system (not shown) is based on publicly available communication networks. There is an inherent risk in the absence of availability on the public communication network that is countered by the leakage control (for example via the control unit 2) - regardless of whether the question is of a manually or automatically initiated filling - autonomously closing the valve 8 when a predefined and adjustable filling amount has been being filled or when the pressure limit 'sufficient' has been reached. In addition, the valve 8 can be configured to autonomously close in the event of failure in the supply voltage.
Logging:
[0046] The leakage control 1 (for example via the control unit 2) logs its activity for documentation purposes as follows:
- occasion for initiation of filling,
- time for initiation of filling,
- operating pressure at initiation of filling,
- occasion for termination of the filling,
- time for termination of the filling,
- operating pressure at termination of the filling and
- filled volume at termination of the filling
Flow limits for manual filling:
[0048] A filling is considered initiated when two flow impulses arrive with a shorter interval than tmin (predefined time minimum), for example 20 seconds at i=10 impulses/litres (18 I/hour). A filling is considered interrupted when two flow impulses arrive with a longer interval than tmax (predefined time maximum), for example 60 seconds at i=10 impulses/litres (6 I/hour).
Safety measures:
[0049] Pressure limits:
Minimum operating pressure: The minimum operating pressure at which the secondary heating circuit may operate.
If the operating pressure drops below this limit, the leakage control (for example via the control unit 2) will give an alarm and activate a relay to stop the circulation pump 11.
'Insufficient': The operating pressure at which the filling should be initiated.
'Sufficient': The operating pressure at which the filling should be terminated.
'High': Operating pressure at which a warning is given.
'Dangerous': Operating pressure at which an alarm is given.
[0050] Volume limits:
Maximum single filling: The maximum volume that may be supplied during a single filling.
Maximum daily filling: The maximum volume that may be supplied (several times) over the course of 24 hours.
[0051] Time limits:
Minimum interval: The minimum time that must elapse between two consecutive fillings.
System monitoring:
[0052] Meter error:
If the operating pressure increases from 'insufficient' to 'sufficient' during a filling, as a filled volume less than a predefined limit is recorded, the leakage control (for example via the control unit 2) will give an alarm and report a meter error.
[0053] Valve error:
If volume flow is recorded with a fully closed shutoff valve, the leakage control (for example via the control unit 2) will give an alarm and report a valve error.
If no volume flow and increasing operating pressure are recorded with a fully open shutoff valve, the leakage control (for example via the control unit 2) will give an alarm and report a valve error.
[0054] Pressure transmitter error:
If the connected pressure transmitter shows characteristics incompatible with the standardized cut surface, a pressure transmitter error is reported.
If the connected pressure transmitter during fillings shows unchanged operating pressure, a pressure transmitter error is reported.
If the connected pressure transmitter indicates operating pressure outside fixed limits, a sensor error is reported.
- a filling pipe (6);
- a supply pipe (3);
- a return pipe (4); and
- a circulation pump (11), advantageously mounted in the supply pipe (3);
and wherein the leakage control system (1) comprises:- a pressure transmitter (5) operatively connected to the return pipe (4);
- a flow meter (7) operatively connected to the filling pipe (6);
- a nonreturn valve (9) or nonreturn control integrated in the filling pipe (6);
- optionally, a manually or electrically (10) operated valve (8) adapted for controlling the flow, such as opening or closing the flow, of medium via the filling pipe (6); and
- a control unit (2) operatively connected to the pressure transmitter (5) and the flow meter (7), wherein the control unit (2) is further configured to calculate the current operating pressure in the secondary circuit of the central heating installation based on input from the pressure transmitter (5) and give an alarm if the current operating pressure is below a predefined minimum operating pressure; and wherein the control unit (2) is configured to receive flow signals from the flow meter (7) and based thereon determine and log the volume of medium refilled in the secondary circuit of the central heating installation via the filling pipe (6), for example in response to the above-mentioned alarm.