Boiler access point protection device

Abstract

The boiler access point protection device comprises a fan (10), a pressure sensor (20) and a check valve (30), the fan (10) being connected to the surrounding environment via a suction port (5) for drawing in ambient air, the pressure sensor (20) being connected downstream of the fan via an airtight connection (6) and the check valve (30) being connected downstream of the pressure sensor via an additional airtight connection (7). A control unit connected to the pressure sensor (20) is provided with a data memory in which at least a low first threshold value and a high second threshold value for the pressure values ​​are stored. If the pressure sensor signal measured by the pressure sensor (20) and transferred to the control unit falls below the first threshold value or exceeds the second threshold value, the presence of an anomaly can be detected by the control unit.

Description

[Technical field]

[0001] The present invention relates to a boiler access point protection device, through which an external device, such as a boiler cleaning device, introducing high amplitude pressure waves, is connected to the boiler through the boiler wall. [Background technology]

[0002] A device and a method for generating high amplitude pressure waves, in particular for cleaning boilers, are known from DE 10 200 03 133 A1. The device comprises an opening for direct release of the gas pressure generated in the combustion chamber. This opening (drain opening) usually ends in a hollow cylinder and leads into the boiler to be cleaned through a boiler access point in the boiler wall. In order to clean a boiler, in particular a boiler in operation, the aforementioned high amplitude pressure waves are generated in the device and introduced into the boiler volume.

[0003] The drawback here is that aggressive gases can flow from the boiler through the boiler access points in the boiler wall into the hollow cylinder, through which they can reach the drain opening and thus the piston valve seat. These gases can degrade the quality of the valve seat, compromising its tightness to such an extent that the rapid pressure rise favorable for cleaning the boiler is compromised.

[0004] US 2005 / 0139996 discloses a protection device for a boiler access point with the features of the preamble of claim 1. A similar protection device is known from US 2005 / 0139996.

[0005] Patent Document 4 discloses an ultra-high pressure hydraulic safety valve with a check valve, in which a pipe access opening is formed in the valve seat. A pressure relief cavity is formed in the upper part of the valve housing, with a drain hole in the side wall of the cavity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 175736 [Patent Document 2] DE 2832076 A1 [Patent Document 3] China Utility Model No. 212004409 Specification [Patent Document 4] China Utility Model No. 210950060 Specification Summary of the Invention

[0007] Based on this prior art, the present invention aims to provide a boiler access point protection device, particularly for a high amplitude pressure wave generator with a hollow cylinder, which prevents such aggressive gases from flowing from the boiler through the boiler access point to the drain opening and thus to the piston valve seat, and whose normal functioning can be monitored by a simple control unit.

[0008] This object is achieved by a protection device for a boiler access point, characterized in that the device comprises a fan and a check valve, the fan being connected to the surrounding environment via a suction port for sucking in the surrounding air, the check valve being connected downstream of the fan via an airtight connection, and the boiler access point penetrating the boiler wall via a pressure hose, the check valve being mounted to close when the fluid pressure in the pressure hose is greater than the fluid pressure in the fan, the airtight connection being provided with an ambient outlet, a control unit with a data memory connected to the pressure sensor, in which at least a first low pressure threshold and a second high pressure threshold are stored. The control unit receives pressure sensor signals measured by the pressure sensor and compares them with the stored pressure thresholds. If the pressure sensor signal is below the first pressure threshold, the presence of an anomaly in the abnormal range is detected.

[0009] If the pressure sensor signal measured by the pressure sensor and transferred to the control unit exceeds the second pressure threshold, the presence of an anomaly in the overpressure range is detected. An anomaly in the overpressure range corresponds to a closed check valve or a clogged pressure hose. If the overpressure range is assigned by the control unit to a closed check valve, a time interval is preferably stored in the control unit, and an anomaly signal is only emitted if the pressure sensor signal in the overpressure range exceeds the predefined time interval. If the device described here is used in a boiler cleaning device which introduces a pressure wave through a boiler access point, this pressure rise causes the check valve to close in accordance with normal operating function for a time interval corresponding to an explosion impulse, so that this state ends after a corresponding predefined time interval and the check valve opens again, then there is no anomaly.

[0010] The abnormal range can be divided into two different abnormal ranges, usually with a third pressure threshold, preferably lower than the first pressure threshold, stored in the control unit. The control unit then divides the aforementioned abnormal range into two sub-ranges when the pressure sensor signal is measured by the pressure sensor and transferred to the control unit. If the pressure value is below the third pressure threshold, the presence of an anomaly in the lower range of the abnormal range is detected as a fan failure or a sensor failure, otherwise a leak or filter problem is inferred. In the diagram relating pressure measurements to volumetric flow rates, only fan failure is shown for the anomaly in the lower range of the abnormal range, because although a sensor failure would show the same measurement, this does not correlate with the actual volumetric flow rate in the still existing air flow.

[0011] By locating a pressure sensor in this gas-tight connection, the function of the fan and the non-return valve can be easily monitored.

[0012] The term fan refers to all types of fans, such as axial fans and blowers, that have an intake side and an exhaust side, and in which air entering from the intake side is compressed and exhausted.

[0013] This allows the boiler access point to be easily protected from the surrounding air without access to an external gas supply, ensuring that fluids from this access point do not reach the external systems being protected, such as boiler cleaning equipment.

[0014] The peripheral outlet may for example be a hole in the wall of the gas-tight connection. Further embodiments are described in the dependent claims. [Brief description of the drawings]

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the drawings, which are given for illustrative purposes only and are not to be construed as limiting.

[0016] [Figure 1] FIG. 1 is a block diagram showing an outline of an apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows fan characteristic curves for operation of the device of FIG. [Diagram 3] FIG. 3 shows a diagram illustrating sensor value ranges of a control unit for operation of the apparatus of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1 is a block diagram showing an outline of an apparatus according to an embodiment of the present invention. A fan 10 is connected to an intake pipe 5, and is installed so as to compress the air around the boiler cleaning apparatus sucked in from the intake pipe 5 and send it to a connection 6. The fan 10 can be designed so as to generate an overpressure of 80 to 200 mbar in the connection 6 connected thereto.

[0018] The continuous connection 6 is designed as a hollow cylindrical element that has little effect on the air flow. It has an outlet 16 on its side, which distributes the air flow generated by the fan 10. A part of it is discharged through the outlet 16 to the surrounding environment, the rest is sent via this connection 6 to the pressure sensor 20.

[0019] The pressure sensor 20 is in particular capable of detecting pressure differences between 0 and 1 bar. A lower limit is essential, while an upper limit is preferably chosen which cannot be reached by the fan 10.

[0020] Downstream of the pressure sensor 20, ambient air is fed under pressure via a check valve 30 and a pressure hose 8 into the interior of said hollow cylinder in the area between the valve seat of said device and the boiler wall. In other words, the feed, for example via the pressure hose 8, takes place outside the boiler access point, so that the ambient air introduced under pressure flows through this access point and the boiler wall towards the gases in the boiler.

[0021] The only condition is that the fan 10 must be powerful enough to blow the surrounding air into the boiler in this way, and the overpressure created by the fan 10 must be higher than the pressure inside the boiler.

[0022] When a cleaning explosion occurs, the check valve 30 prevents the reactive gas from the cleaning explosion from entering the device shown in Figure 1 at the drain opening in the boiler. A sudden pressure rise leaves an air column in front of the check valve 30 in the supply line of the pressure hose 8.

[0023] FIG. 2 shows fan characteristic curves for the operation of the device of FIG. 1. The x-axis shows the volumetric flow rate 50 per unit time, here 0 to 1,000 liters / min (0 to 3 m 3 The y-axis shows the overpressure 60 measured by the pressure sensor 20, here ranging from 0 to 140 millibars. Both the volumetric flow rate 60 and the overpressure 50 are shown as an example embodiment. In other applications, a fan 10 with a higher blowing speed may be used, resulting in a maximum blowing speed of up to 10 m. 3 / min or max 100m 3A volume flow rate 60 of 1000 psi / min can also be generated. The overpressure that this volume flow rate 60 exerts on the boiler, i.e. on the boiler passages, depends on the geometry of the connections and the geometry of the openings 16. This pressure can be up to 1 bar, but usually an overpressure of up to 200 or 500 mbar is sufficient.

[0024] Reference numeral 51 denotes the fan characteristic curve of the freely running fan 10, i.e. the overpressure generated by the volume of air blown per unit time. By mounting the fan 10 in the device of FIG. 1, various operating modes can be realized.

[0025] Reference number 61 indicates a characteristic point of the fan when the non-return valve 30 is open, so that at the beginning of region 6 a direct blow from the fan is possible with a volume flow rate 60 of 470 liters per minute, which causes a pressurization of about 80 mbar to be measured by the pressure sensor immediately behind the fan 10. However, in the region upstream of the non-return valve 30 only a smaller volume flow rate 60 of about 220 liters per minute reaches it, the remaining air leaving the connection through the opening 16. Since the pressure sensor measures the same air column, the pressure when the non-return valve 30 is open is likewise about 80 mbar.

[0026] When a pressure wave is created during operation of the cleaning device, this pressure wave returns to the pressure hose 8 on its way from the cleaning device to the boiler, closing the non-return valve 30.

[0027] When the check valve 30 is closed, all of the entrained ambient air is returned to the outside environment through the opening 16 while the pressure measured by the pressure sensor 20 becomes higher, at characteristic point 62, which corresponds to a flow rate of 320 units per minute through the fan 10. This causes the pressure to rise to approximately 110 millibars.

[0028] However, this directly corresponds to a reduction in the volumetric flow rate at the time the check valve 30 is closed from approximately 220 liters / minute, corresponding to point 71, to a volumetric flow rate 72 of 0 liters / minute with the check valve 30 closed.

[0029] In other words, the decrease in the volumetric flow actually present in the pressure hose 8 changes from the value at point 71, corresponding to arrow 75, to point 72. This is offset by a decrease in the volumetric flow at the pressure sensor 20 between points 61 and 62, corresponding to arrow 65, causing a pressure increase from 80 mbar to a little over 100 mbar. Again, the actual pressure at the check valve 30 is equal to this measured pressure.

[0030] The opening 16 as ambient outlet can have a diameter of, for example, 3 mm to 7.5 mm. However, the diameter of the opening 16 can also be 1 mm to 2 cm, depending on the outgoing flow rate and the pressure increase upstream of the closed check valve 30. The choice of the opening diameter and the type and length of the connection to the environment also depends on the desired overpressure and volumetric flow rate. When using a control unit, the basic arrangement of the measuring points as shown in Figure 3 is essential for the evaluation, as explained below.

[0031] In Fig. 2 three pressure thresholds 112, 113, 114 of 10 mbar, 65 mbar and 95 mbar are shown diagrammatically by way of example, which indicate the pressure values ​​used when describing the functioning of the control unit according to its operating and abnormal ranges.

[0032] The apparatus of FIG. 1 preferably comprises a control unit capable of controlling the performance of the fan 10 and converting the sensor values ​​of the pressure sensor 20 directly into monitored values, thereby resulting in a direct indication of the functionality of the device.

[0033] FIG. 3 shows the ranges of the sensor values ​​of the pressure sensor 20, which are analyzed in the control unit via pressure thresholds for the operation of the device shown in FIG. 1 as an indication or, for example, to shut down the functioning of a cleaning device or a boiler. The sensor value ranges from 0 to, for example, 1 bar, according to the arrow 100. The inventors have found that the measurements of the pressure sensor 20 can be directly converted into monitoring values. From a pressure value 101 of 0 bar up to a pressure value 102, for example, up to 20 mbar as the first pressure threshold 112 shown in FIG. 2, it can be assumed that the pressure sensor or the fan has failed, and the device performs a self-diagnosis and accordingly indicates an abnormal range 140.

[0034] If an optional filter is installed in either connection 6,7, there may be a problem with the filter between the upper limit value 102 of the abnormal range 140 and the next upper limit value 103, for example 90 mbar. This range of values ​​130 is regarded as either a filter problem or a leak in the connection 6,7. The upper limit value 103 is shown in Fig. 2 as pressure threshold value 113. Distinguishing between the pressure threshold values ​​112,113 helps in detecting faults, while the higher of the two pressure threshold values ​​is sufficient to monitor the function.

[0035] Between the pressure values ​​103 and 104 there is an operating range 120, which corresponds to the normal values ​​of the system. The operating range is understood as the operation of the boiler, and not as a period of shutdown of the boiler in case of cleaning being required. Above this upper limit value 104, an overpressure range 110 is reached, which corresponds to a blockage of the system. Gas can then no longer flow through the connections 5, 6, 7, 8 shown in FIG. 1, i.e. the protection provided by the device, which is normally caused by the response of the non-return valve 30, is no longer in effect. This can correspond to the device functioning normally for a short time, when an explosive shock is caused in a boiler cleaning device of the type mentioned at the beginning, which can of course also enter the pressure hose 8 upstream of the boiler wall.

[0036] Therefore, by simple pressure measurement using the differential pressure sensor 20, the operating status of the ventilation system can be monitored via the aforementioned pressure thresholds 103, 104 and, if necessary, pressure threshold 102, by selecting the monitoring ranges 110, 120 and the monitoring ranges 130, 140, either incidentally or individually.

[0037] By utilizing ambient air as a supply source, the supply of protective gas from pressurized gas bottles of the corresponding industrial gas can be largely omitted. [Explanation of symbols]

[0038] 5. Intake pipe 6 Connection 7 Connection 8 Pressure Hose 10 Fan 16 Exit / Opening 20 Pressure Sensor 30 Check valve 50 Volumetric flow rate 51 Free-drive fan characteristics 60 Overpressure 61 Fan characteristic point / operating point for opening the check valve 62 Fan characteristic point / operating point for closing the check valve 63 Fan failure characteristics 64 Characteristics of leak or filter problems 65 Fan measurement change 71 Check valve characteristic point (open) 72 Check valve characteristic point (closed) 75 Check valve measurement change 100 Pressure range (rise value) 101 Pressure value 0bar 102 Third Pressure Threshold 103 First Pressure Threshold 104 Second Pressure Threshold 110 Overpressure Range 112 Third Pressure Level Threshold 113 First Pressure Level Threshold 114 Second Pressure Level Threshold 120 Operating Range 130 Abnormal range - Filter problem or leak 140 Abnormal range - Sensor failure or fan failure

Claims

1. A fan (10) and a check valve (30) are provided. The fan (10) is connected to the surrounding environment through a suction port (5) for drawing in ambient air; The check valve (30) is connected downstream of the fan (10) via an airtight connection (6, 7), The check valve (30) is connected to a boiler access point through the boiler wall via a pressure hose (8); The check valve (30) closes when the fluid pressure in the pressure hose (8) is greater than the fluid pressure in the fan (10); The airtight connection (6, 7) has a peripheral outlet (16), a control unit connected to the pressure sensor (20) is provided with a data memory in which at least a first low pressure threshold (103) and a second high pressure threshold (104) are stored; if the pressure sensor signal measured by the pressure sensor (20) and transmitted to the control unit is below the first pressure threshold (103), the control unit detects the presence of an abnormality in the abnormal range (130, 140); If the pressure sensor signal measured by the pressure sensor (20) and transmitted to the control unit exceeds the second pressure threshold (104), the control unit detects the presence of an abnormality in the overpressure range (110). Protective devices for boiler access points.

2. the overpressure range (110) is assigned by the control unit for closing the check valve (30), and a time interval is stored in the control unit; a fault signal is generated only if the pressure sensor signal in the overpressure range (110) exceeds a predetermined time interval; 2. The boiler access point protection device of claim 1.

3. a third pressure threshold (102) lower than the first pressure threshold (103) is stored in the control unit, and the control unit distinguishes between a leak, a sensor failure, or a fan failure when the pressure sensor signal measured by the pressure sensor (20) and transferred to the control unit is lower than the third pressure threshold (102), indicating the presence of an abnormality in an abnormal range (130, 140); 3. A boiler access point protection device according to claim 1 or 2.

4. the peripheral outlet (16) is a hole in the wall of the gas-tight connection (6, 7); 3. A boiler access point protection device according to claim 1 or 2.

5. The device further comprises a pressure sensor (20) disposed within the gas-tight connection (6, 7).

3. A boiler access point protection device according to claim 1 or 2.

6. The ambient outlet (16) is arranged in the airtight connection (6) between the fan (10) and the pressure sensor (20).

3. A boiler access point protection device according to claim 1 or 2.

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