DE10025470B4 - Method and device for checking the permeability of lines - Google Patents

Abstract

Method for checking the permeability of lines, the line being closed at least on one side to a pressure transducer, characterized in that the permeability of the line is caused by temperature-dependent changes in the volume of a liquid or gaseous medium in the line with a low compressibility via a pressure change dependent thereon is detectable.

Description

The invention relates to a method to check the permeability of lines with the further features of the preamble of the claim 1. The invention also relates to a device to check the permeability of lines with the further features of the preamble of the claim 18th

Generally there is liquid or Gas pipes the risk of this due to contamination in the respective in the lines flowing Medium or for other reasons to grow inside. So it is z. B. possible in water pipes that lime or other contamination of the water in the pipes and clogged it. This danger also exists with Ö1- or Gas lines, however, cannot be recognized from the outside. The erroneous Assumption that a already overgrown line can be different have negative consequences and even involve great dangers.

The problem can e.g. B. with steam or hot water boilers occur to which water pipes are connected. In such Steam or hot water boilers, z. B. shell boilers, it is necessary to carry out a water level control so that a drop in the water level below a predetermined minimum level is excluded. Too much a drop in the water level would do so to lead, that this Flame tube may be exposed, which could have catastrophic consequences.

There is a possibility for water level measurement in the measurement of the differential pressure between the lower range of the boiler (water area) and the upper area of the boiler (steam area). Lines to the outside are connected to the respective area, between which switched a differential pressure meter is. The measured differential pressure essentially corresponds to that hydrostatic pressure inside the boiler at the point where the line connected to the water area is arranged. So is z. B. on the differential pressure meter at a Steam pressure of 10 bar and a water pressure in the lower area of the Boiler of 10.3 bar to measure a differential pressure of 0.3 bar, which corresponds to the hydrostatic pressure. Due to the measured differential pressure the water level can therefore be derived or calculated. It can now happen that due to of chemicals, lime or other contaminants in the boiler water the lines leading to the differential pressure transducer or measuring device are slow overgrowth and as a result no reasonable regulation is possible. One that is no longer continuous on the inside However, the line cannot come from the outside be recognized. To check the continuity there is only the possibility to dismantle the lines or the differential pressure transducer the lines z. B. with the help of a suitable line interior lighting checked can be.

Out DE 197 14 601 A1 a radiator leak test system is known in which an overpressure is generated in a radiator by means of a fluid. A pressure measuring device coupled to the radiator checks whether a pressure change takes place. If a pressure drop is measured, it is concluded that there are leaks in the radiator. A prerequisite for carrying out the pressure measurement is that the temperature of the fluid remains constant.

The DE 198 08 636 A1 describes a method for pressure testing a liquid gas container, in which liquid gas in the liquid phase is transported from the liquid gas container into a spatially separate evaporation container, in which the liquid gas is converted into the gaseous phase by supplying heat. The liquefied gas is then returned in the gaseous phase to the liquefied gas container to be tested and there leads to an increase in pressure up to the desired test pressure. During the pressure increase, an accompanying sound emission analysis is carried out, which provides information about the further usability of the respective container.

The invention is based on the object To provide a method by which the permeability check of cables can be carried out in a simple manner.

This task is characterized by the Features of claim 1 solved. Advantageous further training of the method result from subclaims 2-16.

An advantageous device for execution the method is taught in device claims 18-35.

To achieve the object, it is provided according to the invention that the permeability of the line can be detected by a temperature-dependent change in the volume of a liquid or gaseous medium in the line with a low compressibility via a pressure change dependent thereon. For this purpose, a pressure sensor is connected to the end of the line. The other end of the line to be checked is open or leads into a receiving volume. The method is carried out with a medium, in particular a liquid, which has only a low compressibility. Liquids that are less compressible have the advantage that they expand even with a slight heating and with a non-permeable line a strong pressure increase and thus a safe one Ensure measurement of fluid pressure. With a continuous line, the heated or cooled medium can flow freely in the line. However, if the line is not or hardly open at all, the expansion volume for the medium is so severely limited when it is heated that there is an increase in the pressure of the liquid. Conversely, if the line is not continuous, a cooled medium leads to a drop in pressure. The changing pressure of the medium is expediently detected by the pressure sensor arranged on the line. Accordingly, no or only a slight change in pressure will take place in a continuous line due to the possibility of the medium evading, no or only a slight change in pressure being detected on the pressure sensor. In the case of a non-continuous line, on the other hand, a pressure change which can be measured at the pressure transducer will take place. To check the permeability of lines, the method according to the invention can be carried out in a simple manner without great expense.

The liquid or gaseous medium in the line can cause changes of the volume warmed be so that the liquid expands. The warming can be done with simple heaters and thus provides a less complex method to change the Volume of the medium in the line.

Alternatively, it is also possible that the in medium in the line is cooled to change the volume.

As a medium z. B. water or oil used which already exist in a water or oil pipe is. It is important to ensure that the respective liquid is not mixed with gas, which may distort the measurement result due to the changed compressibility to lead would.

This can expediently be carried out in the Medium located by means of arranged around the lines Heating tapes or heating coils heated the amount of heat transferred to the medium from the outside can be controlled or regulated in a simple manner. The warming by means of Heating tapes or heating coils an inexpensive Heating method due to the relatively simple structure.

The respective medium can also be used of a heating element used in the line can be heated. It is possible that Outside- and internal heating cumulatively, so that even heating of the medium is reached.

In the other variant, at which the medium cooled cooling accordingly inside and outside the management.

The heating or cooling down of the medium near the pressure transducer, so that the entire line is reliable on their Permeability is checked.

In another process variant can the differential pressure between two lines by means of a differential pressure sensor detected be, with only the medium of the pipe to be checked a temperature change experiences. At least the end of the line to be checked is open or leads into correspondingly large Receiving volume. Is the end of the other line open or connected to a recording volume, this line can also by means of of the method according to the invention be checked for permeability. If the line to be checked is continuous in this method variant, no change of the differential pressure, since the heated medium is in the receiving volume or can escape outdoors and thus the pressure of the medium does not change. Likewise, a cooled one Medium with continuous Reduce the volume of the pipe unhindered, so that the pressure of the medium also does not change. However, is the line overgrown, the medium can not in case of heating expand unhindered in the line so that there is an increase in pressure, which leads to a change of the differential pressure leads. The changed one Differential pressure will eventually recorded by the pressure sensor, a signal can be given that the line is to be cleaned.

The pressure of the medium can expediently measured on a pressure gauge in which the pressure sensor is integrated. Corresponding the differential pressure sensor can be integrated into a differential pressure measuring device his. The pressure of the medium can be measured on the (differential) pressure gauge be read or to an associated electronics or software forwarded and evaluated there.

The degree can be particularly advantageous of permeability or growth of the lines based on a pressure-time characteristic, especially a pressure-time diagram, detected become. This can also be used to compare different pressure-time diagrams an explanation of various Factors of the pipe system, e.g. B. growth rate depending of the cable diameter.

The method according to the invention can advantageously at defined intervals performed repeatedly and a statement about the to obtain the time course of the growth of the lines. The The procedure can thus act as an early warning system serve, with which corresponding risks can be avoided.

To ensure that the procedure is carried out reliably at defined time intervals, the test procedure can be repeated automatically. In the procedure, for. B. a secured heat or cold source for changing the temperature of the medium may be provided. So that can a reliable observation of the growth of the lines can be carried out.

The method can be used with particular advantage be linked to an alarm function, which starts at a certain value of permeability the line is activated. This can cause major damage caused by an overgrown Line are caused, reliably prevented.

Additionally or alternatively it can be provided that from a certain value of permeability the line a safety shutdown is activated so that the procedure independently in is capable of major damage or To avoid dangers.

The method according to the invention can with particular Advantage to review the permeability of lines are applied to a receiving volume, for. B. to a pipe, a container or a boiler are connected. A steam or Hot water boilers, z. B. a shell boiler be provided. There is a line with that provided in the large water chamber boiler Water area and the other line connected to the steam area arranged above. The process should be based on the example of the shell boiler as follows explained become.

Conveniently it is yours Water line provided in the lower area of the shell boiler arranged so that the differential pressure (hydrostatic pressure) on one outside the Großwassenaumkessel, Differential pressure transducers arranged between the lines can be detected can. The respective lines are already filled with water, see above that this inventive method simply done can be achieved by first heating or cooling the water from the outside. The boiler room boiler represents the intake volume in which the heated water with permeable Line can flow. The changing differential pressure (at overgrown line) or the constant differential pressure (with continuous line) detected.

A device according to the invention to check the permeability of lines is closed at least on one side to a pressure transducer. The pressure sensor is used to record the pressure of the in the line located medium, which has a low compressibility. Furthermore, a device for changing the temperature of the Medium provided. The liquid heated or cooled in the pipe stretches at continuous Pipe unhindered in it or contracts in it, the pressure of the medium remains constant. However, the line is clogged or overgrown is the expansion volume for the heated medium severely limited in the line, so that an increase in pressure at the pressure sensor is achieved. Conversely, with a cooled medium, there is a drop in pressure detected on the pressure sensor.

The device is characterized by their simple structure and is therefore also simple retrofitted.

As a device for change the temperature, a heating device can be provided in order to to heat the medium in the pipe. Alternatively, change the temperature also a cooling device be provided.

A heating tape can be used as a heating device or a heating coil can be arranged around the line, with which one simple and inexpensive Guaranteed heating of the medium becomes.

Additionally or alternatively a heating element can also be provided in the line, which is a direct one Heating of the medium causes.

A differential pressure sensor can be used as the pressure sensor be provided, which is arranged between two lines. On in this way it does not become the absolute pressure of the medium, but only that increasing or constant differential pressure between the two lines measured. Are both lines open at the end or on Recording volume arranged, so can both lines on their permeability checked become.

The pressure or differential pressure transducer can expediently be integrated into a pressure or differential pressure measuring device so that the changing or constant pressure is measurable.

The end of the two lines can also lead into a common receiving volume, which serves as a collecting container for the in the respective line warmed Medium or for pressure compensation for the cooled Medium serves.

The common receiving volume can expediently a steam or hot water boiler, z. B. a shell boiler be of sufficient volume for the expanded in the pipes liquid provides.

The steam boiler, e.g. B. the shell boiler has a water area and a steam area arranged above it with a line for differential pressure measurement with the respective area of water and steam areas. By simple arrangement a heating device can by means of the differential pressure measurement already taking place also the permeability checked by the respective management become.

Advantageously, a Comparative electronics for creating a pressure-time characteristic for the acquisition the degree of permeability of the Lines are provided, with which a safe control of the lines allows becomes.

For automatic checking of the permeability A control device can be provided for lines after defined time intervals his. Automation makes it easier to carry out the check at certain intervals.

A pressure evaluation unit can also be provided be seen with which the gradual growth of the lines can be controlled.

A safety shutdown and / or an alarm device can serve significant damage or To prevent dangers in overgrown lines.

The invention is based on advantageous exemplary embodiments closer in the drawing figures explained. These show:

1 a schematic diagram of a device for checking the permeability of a line;

2 a schematic diagram of a device for checking the permeability of two lines connected to a differential pressure sensor;

3 a schematic representation of a shell boiler with lines arranged thereon for measuring the differential pressure;

4 a time-pressure diagram, as well

5 a schematic representation of a shell boiler according to 3 with advanced functions.

First up 1 Referred. numeral 1 denotes the device in its entirety with which the method for checking the permeability of lines is carried out. The administration 2 is at the end by means of a receiving volume 3 completed. However, it is also possible that the line 2 is simply open and ends up outdoors. At the other end of the line is a pressure gauge 4 arranged with which the pressure of the in the line 2 medium is measured with a low compressibility. In the pressure gauge 4 a pressure sensor is integrated. To check the permeability of the line 2 a temperature-dependent change in the volume of the liquid or gaseous medium in the line is carried out. A pressure change dependent thereon is detected by the pressure sensor. To change the volume, the liquid or gaseous medium in the line can be heated so that the medium expands and with a continuous line 2 in the recording volume 3 flows. This possibility of evading the medium does not or hardly changes the pressure of the medium and on the pressure measuring device 4 an approximately constant pressure can be measured before and after heating the medium. However, is the line 2 not continuous, the expansion volume for the medium is limited and there is an increase in pressure on the pressure gauge 4 is measurable. The method uses a liquid with a low compressibility, in which even a slight heating ensures a strong increase in pressure. For example, water or oil can be used as the liquid. However, there is also the possibility that the medium in the line is cooled to change its volume. The medium contracts, ie its volume decreases, with continuous conduction 2 a pressure equalization, ie a post-flow of z. B. Air on the receiving volume 3 he follows. This pressure equalization option does not change the pressure of the medium and on the pressure measuring device 4 an approximately constant pressure is measured before and after the cooling of the medium. If the line is not continuous 2 on the other hand, there is a pressure drop on the pressure measuring device 4 is measurable.

The process uses a medium especially a liquid used with a low compressibility, at which already a little warming or cooling guarantees a sharp increase or decrease in pressure. So as a liquid medium for example water or oil can be used, which has the advantage that a water or oil pipe be checked in a simple manner can, since the test liquid already on the line.

The liquid or gaseous medium is circulated around the pipe 2 arranged heating coil 6 heated. It is also possible to get the line 2 Put on heating tapes and / or a heating element in the line 2 provided. The heating coil 6 is at one end of the line 2 near the pressure gauge 4 arranged so that the entire line in a reliable manner 2 is checked for its permeability.

2 shows an alternative structure for performing the method according to the invention. Between two lines 2 . 2 ' a differential pressure sensor is arranged. The differential pressure sensor is in a differential pressure measuring device 5 integrated. On both sides of the differential pressure measuring device 5 is a heating coil 6 . 6 ' around the respective line 2 . 2 ' arranged, only the liquid or gaseous medium of the line to be checked 2 or 2 ' is heated. On every line 2 . 2 ' is a receiving volume at the end 3 . 3 ' arranged, in which the heated medium, e.g. B. the heated liquid can flow with a continuous line. To carry out the method, the liquid or gas in the line to be checked (e.g. 2 ) by means of the heating coil z. B. 6 heated. With continuous line 2 the warmed medium soaks into the receiving volume 3 from, the differential pressure between the two lines 2 . 2 ' does not change. However, is the line 2 no longer continuously, the pressure of the heated medium increases and there is a change in pressure on the differential pressure measuring device 5 is measured and can be read there. The same procedure can be used to check the permeability of the line 2 ' be carried out, only the liquid or gaseous medium contained therein by means of the heating coil 6 ' is heated. When the Medi cools down the same applies as for the description 1 ,

With the respective methods it is possible that the degree of permeability or the growth of the lines 2 respectively. 2 ' on the basis of a pressure-time characteristic, in particular a pressure-time diagram. 4 shows such a pressure-time diagram, with the time t from the time of heating being plotted on the abscissa and the pressure of the medium p or the differential pressure being plotted on the coordinate. Three measurement curves are entered in the diagram, the dashed line representing the pressure curve of a completely overgrown line 9 shows. The solid line represents the measurement result of a partially overgrown line 10 The dash-dotted line, which is parallel to the time axis, illustrates the measurement curve of a continuous line 11 at which the pressure p remains constant.

A particularly advantageous application of the method is in 3 shown. To a shell boiler 7 or generally a steam or hot water boiler, which has a water area and a steam area arranged above it, are lines with the respective area 2 . 2 ' connected for differential pressure measurement of water and steam areas. The two lines 2 . 2 ' are outside the boiler room 7 coupled to a differential pressure transducer, which in a differential pressure measuring device 5 is integrated. The pipe connected to the water area 2 ' is in the lower area of the shell boiler 7 arranged so that the hydrostatic pressure of the water is recorded as a differential pressure and thus to the water level in the boiler room 7 can be closed. When the water level changes, the hydrostatic pressure of the water and thus the measured differential pressure also change. On the lines 2 . 2 ' are shut-off valves 8th attached for example for repair measures. To check the permeability of the lines 2 . 2 ' are on both sides of the differential pressure device 5 heating coils 6 . 6 ' arranged. The method according to the invention for checking the permeability of the lines 2 . 2 ' now takes place according to the description 2 , but with a common liquid reservoir for the two lines 2 . 2 ' is provided. The liquid storage container is the shell boiler 7 , To check the pipe connected to the water area 2 ' this pipe, which is already filled with water, must be by means of the heating coil 6 ' be warmed. With continuous line 2 ' the water expands into the shell boiler 7 off and there is little or no change in the differential pressure. The same applies to the inspection of the line connected to the steam area 2 , With the aid of the method according to the invention it is therefore possible to arrange the lines arranged on the large water space boiler or another steam or hot water boiler for differential pressure measurement 2 . 2 ' without disassembling them, to check their permeability in a simple manner.

On the respective device a comparison electronics (not shown in the drawing figures) be provided for creating a pressure-time characteristic, which is the degree of permeability of the lines detected.

The respective method for checking the permeability of the lines can be carried out at defined time intervals so that a statement can be made about the increase in time of the lines. This method expediently takes place automatically, for which purpose a control unit 12 is provided (cf. 4 ). In addition, according to the device 4 a pressure evaluation unit 13 arranged, with which a good control of the time course of the growth of the lines and the individual measurement is possible. An alarm device 14 turns on at a certain rate of increase or degree of growth. The alarm device 14 and / or the pressure evaluation unit 13 can be coupled with a safety shutdown (not shown in the drawing) so that damage or dangers due to an overgrown line can be reliably avoided.

The invention provides a simple, but equally extremely effective Procedure for checking the permeability of lines.

1

contraption

2

management

2 '

management

3

receiving volume

3 '

receiving volume

4

pressure gauge

5

differential pressure gauge

6

heating coil

6 '

heating coil

7

Shell boilers

8th

shut-off valve

9

completely overgrown line

10

partially overgrown line

11

continuous line

12

control unit

13

Print evaluation unit

14

alarm device

Claims (35)

Method for checking the permeability of lines, the line being closed off at least on one side to a pressure transducer, characterized in that the permeability of the line is influenced by temperature-dependent changes in the volume of a liquid or gaseous medium in the line with a low level Compressibility can be detected via a pressure change dependent thereon. A method according to claim 1, characterized in that at the pressure transducer arranged on the line the pressure change of the liquid or gaseous Medium recorded becomes. Method according to one of claims 1 or 2, characterized in that that this Medium in the line is heated to change the volume. Method according to one of claims 1 or 2, characterized in that that this medium in the line is cooled to change the volume. Method according to one of the preceding claims, characterized characterized that as Medium water is used. Method according to one of the preceding claims 1-4, characterized characterized in that oil is used as the medium becomes. Method according to one of the preceding claims, characterized characterized that the Medium is heated by means of heating tapes or heating spirals arranged around the line. Method according to one of the preceding claims, characterized characterized that the Medium is heated by means of a heating element inserted in the line. Method according to one of the preceding claims, characterized characterized that the Heating or cooling of the medium near the pressure transducer. Method according to one of the preceding claims, characterized characterized in that the Differential pressure between two lines by means of a differential pressure sensor detected with only the medium in the pipe to be checked the temperature change experiences. Method according to one of the preceding claims, characterized characterized in that the (Differential) pressure transducer integrated in a (differential) pressure measuring device at which the (differential) pressure of the medium (s) is measured becomes. Method according to one of the preceding claims, characterized characterized in that the Degree of permeability or growth of the lines based on a pressure-time characteristic, in particular a pressure-time diagram. Method according to one of the preceding claims, characterized characterized that the Procedure is carried out at defined time intervals. A method according to claim 13, characterized in that this Procedure is carried out automatically at defined time intervals. Method according to one of claims 13 or 14, characterized in that that this Method is coupled with an alarm function, which from a certain Value of permeability the line is activated. Method according to one of the preceding claims, characterized characterized that from a certain value of permeability a safety shutdown is activated on the line. Application of the method according to one of the preceding Expectations at a receiving volume (pipe, container, boiler), especially one Steam or hot water boiler, connected lines, the differential pressure between two Areas in the receiving volume by means of one with the respective Area connected line and a differential pressure transducer arranged between the lines detected becomes. Device for checking the permeability of lines, the line to be checked ( 2 ) is closed at least on one side to form a pressure transducer, characterized in that - on the line ( 2 ) a pressure sensor for detecting the pressure of the medium in the line, which has a low compressibility, and - a device for changing the temperature of the medium are provided. Device according to claim 18, characterized in that the Device for changing the Temperature of the medium is arranged near the pressure sensor. Device according to one of claims 18 or 19, characterized in that that as Device for changing the temperature of a heating device is provided. Apparatus according to claim 20, characterized in that a heating tape around the line ( 2 ) is arranged. Device according to claim 20, characterized in that a heating spiral ( 6 ) around the line ( 2 ) is arranged. Apparatus according to claim 18, characterized in that a heating rod in the line ( 2 ) is provided. Device according to one of claims 18-23, characterized in that a differential pressure sensor is provided as the pressure sensor, which is between two lines ( 2 . 2 ' ) is arranged. Device according to one of claims 18 - 24, characterized in that the pressure sensor in a pressure measuring device ( 4 ) is integrated. Apparatus according to claim 24, characterized in that the differential pressure sensor in a differential pressure measuring device ( 5 ) is integrated. Device according to one of claims 18 - 26, characterized in that on both lines ( 2 . 2 ' ) a receiving volume at the end ( 3 . 3 ' ) is arranged. Device according to one of claims 18-27, characterized in that the end of the two lines ( 2 . 2 ' ) in a common recording volume ( 3 ) leads. Device according to claim 28, characterized in that this common intake volume is a steam or hot water boiler. Apparatus according to claim 28, characterized in that the common liquid receiving container is a shell boiler ( 7 ) is. Device according to one of claims 29 or 30, characterized in that the steam or hot water boiler ( 7 ) has a water area and a steam area arranged above it, a line ( 2 . 2 ' ) is connected to the differential pressure measurement. Device according to one of claims 18 - 31, characterized in that a comparison electronics for creating a pressure-time characteristic for the detection of the degree of permeability of the lines ( 2 . 2 ' ) is provided. Device according to one of claims 18 - 32, characterized in that a control device ( 12 ) for automatic checking of the permeability of cables ( 2 . 2 ' ) is provided after defined time intervals. Device according to one of claims 18 - 33, characterized in that a pressure evaluation unit ( 13 ) is provided. Device according to one of claims 18 - 34, characterized in that a safety shutdown and / or an alarm device ( 14 ) is provided.