Installation to monitor water level in a boiler.

The present invention relates to a device for monitoring the water level of a boiler according to the preamble of claim 1. In addition, the present invention further relates to a boiler using the aforementioned device and a method for checking the function of water level sensors of a device for monitoring the water level of a boiler ,

A boiler to generate steam, hot or warm water having a water reservoir, which is to have a certain set filling height. This set filling height is monitored automatically by water level sensors, which generate in case of loss of contact with water a signal. Regularly the set filling height or the set Füllhöhenbereich is detected and controlled by a plurality of water level sensors. For safety reasons, write individual authorities for a periodic review of water level sensors.

A device of the generic type is described in DE-A-30 13 019th This known device comprises a housing, which is located in the water tank of a boiler and in its interior has a water level sensor. The housing has a passage so that the water level in the water reservoir and the housing can balance each other. To check the water level sensor, that is, to its exposure, the known device has a feed, via which, if required, compressed air is supplied to the interior of the housing, whereby a pressure-induced lowering of the water level inside the housing data takes place until the water level sensor is exposed and its function can be checked. However, this technique has proved in practice to be extremely costly, since on the one hand expensive gases (eg nitrogen) must be provided, on the other hand, high equipment complexity of valves, pipes, seals, etc. is caused.

The object of the present invention is to provide a means for monitoring the water level of a boiler, which allows a review of the water level sensors during operation of the boiler, avoiding of injecting a gas and moreover in a particularly simple and cost-effective manner should be producible. In addition, the device at low cost in existing plants should be retrofitted.

The above object is achieved in the generic device according to the invention in that a discharge line is provided which permits removal of the water located in the housing in a space located outside of the boiler until exposing the positioned at the lowest point sensor. It has been found that located through the use of a derivation due to the prevailing pressure difference between the interior of the boiler or of the housing of the device to the outside (z. B. atmosphere) the water in the housing through the draw tube through autonomously in a outside the boiler space flows with the result that the water level falls within the housing of the device compared to the water level of the boiler, so that all the water level sensors are exposed. The lowering of the water level in the housing is very fast compared to the lowering of the total boiler water level. The necessity of injecting nitrogen gas or the like is eliminated. Nevertheless, all this water level electrodes can also be checked during operation, switching off is not necessary. The invention has the advantage that it eing for a fraction of the previously necessary cost even with existing boiler systems can are setup, ie retrofitting is possible. It is only necessary to connect the interior of the housing via a discharge line with a space of lower pressure.

Conveniently, the discharge tube is designed lockable. This ensures that for now bears the predominant within the boiler or within the housing pressure within the sampling tube in the closed state, so that the prevailing pressure gradient for water drainage and thus for lowering the water level can be fully utilized within the housing of the device.

An exact influence of the water level inside the housing can be achieved in that the barrier is finely regulated by it.

According to a further embodiment of the device according to the invention the discharge tube is provided within the housing.

This extraction pipe is advantageously connected to a shut-off valve located outside the housing, the actuation of which ensures the lowering of the water level inside the housing.

According to another expedient embodiment provides that the sampling tube is attached to the external of the boiler top of the housing. For assembly of the sampling tube, it is here only necessary to provide a hole in the cover and either connect the sampling tube releasably (eg, by screwing) or insoluble (for example by welding) to the housing cover. Retrofitting is easy and causes compared to the prior art, only a fraction of the cost.

Conveniently, a removable cover is provided at the top of the boiler, where the sensors and the extraction pipe are attached. This is particularly advantageous with the use of mechanical sensors that need to be replaced frequently or controlled. The device may in this case be opened by removing the cover in a simple manner and the sensors are replaced.

According to another expedient embodiment of the device according to the invention the bottom, in the water space of the container is tapered or funnel-shaped. The arrangement of the sensors and the extraction tube may be disposed corresponding to the chamfer of the lower end of the housing. This refinement has the advantage that dirt particles located within the housing can be collected at the lowest point of the container and discharged through the boiler water.

To support the derivation of water and thereby justified lowering the water level within the housing may be connected to a suction device PURSUANT another embodiment of the present invention, the derivative or the extraction tube.

Appropriately, several discharge pipes can also be provided per enclosure.

The present invention further relates to a method for checking the function of the water level sensors of a device for monitoring the water level of a boiler. This method is characterized in that is produced by a discharge or a discharge tube which, or whose lower opening below the position of the lowest sensor is arranged to connect to a space with lower pressure, whereby water in the derivative or the extraction tube rises and the water level in the housing of the device is lowered as compared to the water level in the water reservoir until the lowest sensor is no longer located under the water, then the functionality of the sensor or sensors is tested using known measures, and subsequently the connection is closed whereupon the current water level in the housing of the device in the housing goes back to the conditions prevailing in the boiler water level.

Advantageously, the opening or the closing of the connection is made manually or automatically using a time control.

Finally, the present invention relates to a boiler to generate steam, hot, or hot water with a furnace or electric heating or gas heating, a heat exchanger to transfer the thermal energy of the flue gas in the water and a water reservoir. The boiler according to the invention is characterized by a device for monitoring the water level in the water reservoir according to any one of claims 1 - 12 out.

The following is a practical embodiment of the invention with reference to the drawings in more detail. Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>a greatly simplified schematic representation of a steam boiler boiler;</dd><dt>FIG. 2</dt><dd>an enlarged view of the device according to the invention for monitoring the water level of the boiler of Figure 1 during normal operation.</dd><dt>Fig. 3</dt><dd>an enlarged view of the device of FIG 2 but using a located outside the housing discharge. </dd><dt>Fig. 4</dt><dd>the device of FIG 2 with a lowered water level inside the device for checking the water level sensors. and</dd><dt>Fig. 5</dt><dd>the device according to FIG. 3 with a lowered water level inside the device for checking the water level sensors.</dd></dl>

Number 1 in FIG. 1 denotes a boiler, for example, an exhaust gas-heated steam generator or the like. The boiler includes a combustion chamber 2, in which a flame 4 is generated. The case generated, the hot exhaust gases are passed through a heat exchanger 8, for example in the form of an annular gap exchanger through the water reservoir 7 and give their heat to the surrounding water 3 from.

The exhaust gases leave the boiler at the output 9. The steam leaving the boiler 1 at the output of the 22nd

Inside the boiler there is a certain water level, which is characterized in FIG. 1 A.

To test this water level, a device 10 is provided which comprises water level sensors z. B. in the form of water level electrode, vibrating body, etc. to determine the respective water level, which are connected to an off the boiler controller 5. Depending on the water level of the electrodes 12 - found 14 water levels, is the boiler supplied water via a pump 6 or possibly discharged water.

Fig. 2 shows an enlarged view of the device 10 for monitoring the water level. The device 10 comprises a sleeve-like housing 11 which is closed at its top and bottom in each case with a lid 18 and 15 respectively.

Firmly attached to the lid 18 are three sensors in the form of water level electrodes 12, 13 and 14, which are arranged to form a water-level target range to ensure the regulation of water levels at different heights. The water level electrodes 12-14 generate a signal which is passed to an out of the boiler control 1 5 in the case of lowering the water level within the device 10 under the respective electrode. The controller 5 is connected to the pump 6 in conjunction which the boiler 1 supplies water if necessary.

The housing 11 of the device 10 has on the underside an opening 17 which connects the interior of the device 10 with the water reservoir of the boiler 3 first Furthermore, located on the top of the housing 11 of the device 10 a further opening 16, which ensures a connection of the vapor chamber with the interior of the device 10th

The lower end of the device 10 is closed with a cover 15th

The device 10 further includes an extraction tube 20, which is also mounted in the cover 18 and the lower end is located below the position of the lowest water level electrode 14th

The sampling tube 20 is connected to a discharge line in which a fine adjustment valve 21 is provided.

Due to the prevailing compared to the outside of the boiler inside the boiler 1 higher pressure is the water in the device 10 derived by opening the fine adjustment valve 21, whereby the individual water level electrodes 12 - 14 are gradually exposed and their function can be checked here.

In the embodiment of the present invention shown in FIG. 3 the extraction pipe 20 is not within the casing 11 but outside, that disposed in the water reservoir 7 and steam space of the boiler 1.

As shown in Fig. 4 or Fig. 5, the water level B can be lowered a maximum to the lower end of the extraction tube 20 within the device 10 as compared to the water level A in the water reservoir 7 of the boiler 1.

The dimensions of the sampling tube 20 and the passage holes 16 and 17 must be made so that the lowering of the water level B for water level A is done as quickly as possible.

The verification of the function of the water level electrodes 12-14 is effected in that the shut-off valve 21 is opened. The water rises due to the pressure difference on in the sampling tube, causing the water level lowers within the establishment 10th The functionalities of the device 10 water level electrodes 12-14 is then visible as soon as they lose contact with water. In this case, signaling must be carried out. Subsequently, the gate valve 21 is closed, whereupon the current water level B goes back to the conditions prevailing in the boiler water level 11 A within the establishment 10th

The opening or closing of the stop valve is expediently carried out manually or automatically.

The invention provides a very simple and, moreover, cost-effective method of checking the operation of the water level of a boiler equipment without the entire boiler water level would be lowered. Furthermore, the invention provides the advantage that existing plants already are easy and can be retrofitted at relatively low cost. All in all, the invention relates to the technical field of boiler construction is a special enrichment.

LIST OF REFERENCE NUMBERS

<dl id="dl0002"><dt>1</dt><dd>boiler</dd><dt>2</dt><dd>combustion chamber</dd><dt>3</dt><dd>water</dd><dt>4</dt><dd>flame</dd><dt>5</dt><dd>boiler control</dd><dt>6</dt><dd>pump</dd><dt>7</dt><dd>water reservoir</dd><dt>8th</dt><dd>heat exchanger</dd><dt>9</dt><dd>exit</dd><dt>10</dt><dd>Means for monitoring the water level</dd><dt>11</dt><dd>housing</dd><dt>12</dt><dd>Water level electrode</dd><dt>13</dt><dd>Water level electrode</dd><dt>14</dt><dd>Water level electrode</dd><dt>15</dt><dd>cover</dd><dt>16</dt><dd>Passage opening</dd><dt>17</dt><dd>Passage opening</dd><dt>18</dt><dd>Lid / top</dd><dt>20</dt><dd>sampling tube</dd><dt>21</dt><dd>Fine adjustment valve</dd><dt>19</dt><dd>exit</dd></dl>