DE1919177C3 - - Google Patents

Description

The invention relates to a device for gas leak detection in underground gas supply networks, with a suction cup that can be placed on the earth's surface and is connected to a suction pump via a line is. which sucks in an air sample and sends it to a flame ionization detector, which the Air sample examined for the presence of a constituent typical of the gas in question.

A gas detection vehicle is known (Neue Dcliwa magazine, P. 419 ff. Of November 1, 1964), on the front of which a suction bar uncj two sided Borrowed suction funnels are mounted, with soft the vehicle over a monitored, underground run the laid gas pipeline at low speed. The suction bar as well as the two side ones Suction bells are guided a short distance above the earth, road or similar surface, and they continuously suck in air samples. The aspirated air samples are then by means of a Flame ionization detector analyzed. The examination result is on a control and. Display device brought to the display. Step into the sucked Air samples the typical gas component aiii for the pipeline to be monitored, e.g. Methane in a natural gas pipeline that is to be monitored, this leakage gas is shown in the control and display device registered.

A hand-held detector can be connected to this known gas detection vehicle as a fourth flushing device, which is connected to the vehicle's suction pump via a hose. This downwardly open, can be placed on the suction cup Frdoberfläche is served by an additional Bedienungsmiinn leading off the surface in the region of a laid underground gas pipe and thereby the suction cup at certain intervals obliquely au ^r the road surface or the like touches the Earth's surface.

Characteristic of this known Gaslecksuchgerai that the suction cups, the sloping au the surface ^f attachable hand sensing bell, act only as a collecting funnel and detect only the leakage gas which is already diffuses through the soil layers and emerged from the soil upwardly into the atmosphere. Is the surface of the earth to be examined moist or wet. Due to the high gas diffusion resistance, little or no gas can escape upwards. Leak gas escaping beneath the surface of the earth is then absorbed in the soil moisture until the moisture is saturated with gas. In addition, leakage gas escaping from underground pipe networks is absorbed on the surface of the grains of sand in the ground until their surface can no longer absorb gas. It follows that in the ground, in particular in moist soil, this does not emerge at all or, if necessary, only emerges from the surface of the earth with a long time delay after its formation and can be detected with the known leak detector. Leak gases that are heavier than air, e.g. propane, do not emerge from the surface of the earth at all and cannot be detected with the known suction device (worksheet G 465 of the DVGW regulations regarding guidelines for the monitoring and repair of gas pipe networks for operating pressures up to 10 000 mm WS «, pp. ^Ί and 8).

In addition to the well-known gas leak detector with. de; Suction bells, which only act as a collecting funnel, is a vapor leak detector with a manual known to lead probe that has no collecting funnel (USA.-Patent 2,947,166). With this one Device with what leak; can be detected in steam pipelines and steam boilers, the air sample in the probe is sucked over a hygroscopic salt, which is placed between two electrodes under voltage Iie * l. Contains the aspirated air sample coming from a steam trap Moisture, so this, is absorbed by the hygroscopic sab, and that between the two Electric current flowing through the electrodes is proportional to the humidity of the air sample being examined. With only traces of steam and no traces of gas can be detected with this known device. For monitoring The known device is unsuitable for underground gas pipe networks.

When testing the tightness of a circumferential

i 919 177

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and ίΐ ^ ϊν ¹ "· ^(Zei ^ hriit Hen- is fed by the oxygen that is in the sucked in,

dt 1rhw, ä, ^{IUninßl mi} ' ^Nr · ^In <contained gas sample arriving at the detector .st.

ί _7U 1 JrJ ^{na U e} ; ^nen "" »running If you weren't going to move between the pressure side of the vacuum

ί Irin ^§ vl · ^C '" ^mn » ™ £ open the funnel with the aid of the pump and the detector

lemmnngs vakuumu.ch: απ the weld seam 5 interposed, then the justified rule would exist

ftii · «V ⁿ ^ ^{lcbd £ rGM} ™ ^{ri! 1} s drive of the extinguishing of the burning in the detector

_m of RohrschweiBnaht aufhegt he has one. Out flame due to lack of oxygen because of the suction cup

Hehmung, de via a vacuum connection with one of the device according to the invention in characteristisr.ier

Mass spectrometer connected ^ is. i.- can be placed on the surface of the earth in an airtight manner,

■ pohrieiiuhg is helium as r ,,. ^ _We , _ _{lo so that thereby the delivery} rate of the sucked

, bes sicii with an undichiheii of the _2U subdivide gas sample and in particular of sucked air

-The pipe weld in the recess of the rubber can practically go back to NuU,

Mirings collects and registers from the mass spectrometer To improve and secure the seal

is freezing. This welding test is experienced for the suction cup against the surface of the earth

(^ leak monitoring of underground pipes, ₅ proposed another feature of the invention

_§ eue also unsuitable. _{geOi that the suction cup} f three concentric to one another

Further, still one-Prueinrichumi _on Ermit- having arranged edge webs. With a sealing

LELN leaks in hollow body andr _n known tune "e ° s harder soil surfaces pass the

(German patent specification? 2! <· ': · οι., ","., -: ...... _{Jie 2U margins or at} least their lower edges

■ investigating level height!;. , _;: ,.:. ν.πύ, ·: ·. hollow ₂₀ of a soft elastic Mate .ial.

bell-shaped body ^ u:, -. [, <_w; _ri _; _de , _{niit After} another M <kmal of the invention

hooked onto an ulas indicator tube · ;; ; ,,. ;, _v , _e iehem can be the edge web of the suction cup; made of metal

themselves in a foam plug rviinti ..: '■: _. ■■■ :, _{/ u} underneath and have a cutting edge-like lower edge.

iUcheiKie hollow body wall inncr ^ ii-, (j ..., -, -, ckenför- This embodiment of the invention is used

-shaped body or a leak cm, ·, h: -.- u>_{l:; i} in Ie = ■ = dung vorzusiswcise at compliant, soft top

only the one created by the i.eck -wrvor ^ r :: ^ ·. Surfaces, for example in meadows or arable land.

idiuck or suppression ies.igc-c!:! ■ _c; i _;:.:. by the rather metallic edge web of the suction cup is then

■ which ι the foam plugj :, n, A-yc! . Jaiiohr according to a further feature of the invention on its

after ü.r one or after de; - and · .- '. - ·.; · · -..-,., "■ .cr beautiful outside and / or inside at a distance \ on his-

ben ν. ι ti. Also this test series ...:;, ... r _{: V} - which 30 ner lower edge with a protruding, soft-

as V: result an over- or Ur.:, :: \ rv-k erallen stic sealing ring provided on the one hand the

is, is to the Oberwachuns untcrirtl,: -. ". ·. Experienced penetration of the metallic edge web in one

Gasroi;! Lines ungecignei. "limited yielding soil and the other

The invention has the object 7 \.:. Xr, r ,, L an overall an additional sealing against the ground

advises to create gas leak detection, mif gum. ^; . ■ Leak 35 causes.

seek without destroying the Erdohc-nit.h ".-; I and" "The following is the invention on the basis of the

especially in the case of dense, a

contradicting surfaces, and in particular explained in more detail. It shows

dere. irh can then be carried out when the 'Fig. I a schematic side view and

the surfaces concerned are wet. _4c Fig. 2 is a corresponding front view of a

The solution to this problem consists of a criiüdungsge embodiment of the gas leakage according to the invention

appropriate in the combination of features. : ial. '> "search device.

3 shows, in an enlarged representation, a perpendicular

a) the suction cup has at least one middle section through an embodiment of the top-of-the-tier animal surface airtight in the gripping edge bar 45 of the saucepan,

comprises _F "i g. 4 is a bottom view to F i g. 3,

b) the suction pump has a negative pressure of about F i g. 5 shows a representation corresponding to FIG. 3 0.8 at generating vacuum pump and another embodiment of the suction cup,

c) to the pressure line of the vacuum pump in Fi g. 6 shows a connection to FIG. 5 and FIG

the free atmosphere of opening funnels is shown. 7 a schematic side view of another

is se'zt, within which the inlet opening rer. Embodiment of the gas leak detector.

the suction line of a Tn feeding the detector is shown in FIG. and 2 is a maneuverable-s

small suction pump is arranged. Gas leak detection device shown, which is a general with 1 designated chassis frame,

In the device according to the invention, the suction cup 55 is on the two wheels 2 on a common axis 3

can be placed airtight on the surface of the earth and are stored. On the chassis frame 1 are the

With the high negative pressure within different 3 parts of the device, the air sample is expediently and clearly

of the suction cup at least partially from the under the rather and space-saving arrangement. the

Layers lying on the surface of the earth sucked out. suction cup 15 to be described in detail

According to the invention 60, the sucked gas sample is fed to a vacuum pump 6 via the suction line 4.

not directly closed to the flame ionization detector, to drive a generator on the

but the pressure line of the vacuum chassis frame 1 is mounted. The pressure line?

The pump opens out into the free steam generator via a funnel. The vacuum pump 6 opens out via a funnel 8

atmosphere, d. i.e., the gas sample is released into the free atmosphere together with at-. In the funnel 8 this is ίίπ J ^

atmospheric air supplied to the detector. Since 65 the suction line 9 of a small suction pump 11

it is avoided with certainty that in the case of level, which is mounted in the detector 10 and the

The vacuum ar »the suction bell the flame in the from the one emerging from the funnel8. Air sample

Flame ionization detector goes out. This flame leads a small part of it to the detector JO.

In the housing of the detector 10 is a schematic Fireplace 12 shown for the flame ionization chamber. The detector 10 also contains the battery for the suction pump 11 and a gas bottle for the fireplace insert. Compared to the handle 13 of the Driving frame 1 is the control and on this Display device 14 mounted.

With reference to FIGS. 3 and 4, a first embodiment of the suction cup 15 will now be described will. This consists of a base plate with a threaded connector in the middle on the top 23 is molded. the bore of which leads to the underside of the base plate 15. In this hole is a replaceable filter 20 is arranged, which in a conventional manner removes the dust from the suctioned Catches air. The threaded connector 23 is used for exchangeable attachment of the suction cup 15 to the Suction nozzle 4. for this purpose a corresponding threaded sleeve 22 at its lower end having.

In the underside of the base plate 15, in the embodiment according to FIGS. 3 and 4, three concentric ones Edge webs 16, 16 'and 16 "let in, either as a whole made of flexible material, such as, for example, foam rubber, consist of a foam rubber seal, or at least on their "n'.crkante" 16 η wear. In this way, the lower edges of the edge webs 16, 16 'lie. 16 "tight fitting against an earth or road surface or the like. so that under the bore of the base plate 15 in Inside the edge web 16 ″ from the vacuum pump via the suction line 4 a high vacuum and practically no "side air" can penetrate from the side.

The F i g. 5 and 6 show another embodiment of the suction cup 15, in which a metal web band 17 is welded to the base plate ils the edge of the suction cup is. which has a sharpened lower edge 17 a. This embodiment of the suction cup 15 can be used, for example, on soft floors. Meadows and the like. Use, the cutting edge 17a in the Penetrates soil. To prevent the metal web band 17 from penetrating too far as a result of the vacuum pump 6 to prevent vacuum generated in a soft floor, one can on the outside and / or Inside the metal web band 17 sealing rings 42 fasten from, for example, foam rubber, which, when they rest against the surface of the earth, an additional The metal web strip 17 forms a seal against the flow of outside air.

The "suction cup 15" or the suction nozzle 4 is provided with a vent valve as shown in FIG. 2 21, which is connected to an actuating handle 18 on the handle 13 via a Bowden cable 19 is so that the operator can open the valve 21 by operating the handle 18 to after Completion of a sample in the suction cup 15 to release the vacuum so that the suction cup 15 is easily lifted can be.

In operation, that shown in Figs Device driven to the place of use, for example a street under which a gas pipeline is laid and there according to the representation m the FIG. 1 and 2 set up above the gas pipeline in such a way that the suction cup 15 rests tightly against the road surface with its edge webs 16. at Continuously running vacuum pump 6 then quickly creates a high negative pressure of, for example, approximately 0.8 at under the suction cup 15, the height is monitored with a manometer, not shown will. As a result of this vacuum under the suction cup 15, even with dense road surfaces, as beispicls wise concrete ceilings, with low-porosity soils and even with wet soils from the topmost road surface or soil layers sucked out the air present there, which in the presence of a Leaks in the gas pipe contains traces of gas, and this sucked in air is blown out through the funnel. A small part of this air is drawn from the suction pump 11 fed to the detector, which in the presence of traces of gas on the control or display device 14 gives a leak indicator. Without the interposition of the funnel 8, the ideal Completion of the suction cup, the delivery rate almost> is going to zero. Then in the detector the Flame extinguished due to lack of oxygen. Therefore, the vacuum pump 6 promotes a larger one Air volume from which the smaller amount of air required for the detector is passed through the suction pump 11 is removed. After completing the Probcnnal.me the operator operates the operating lever 18 and thereby lifts the vacuum in the Suction cup 15. The device can now be tilted so that the suction cup 15 is from Soil solves, whereupon the device is driven with the wheels 2 to the next sampling point, where the process described begins anew.

Another embodiment of the device is shown in FIG. 7 in a schematic side view. Those parts which, in the same or a corresponding form, also in the embodiment according to FIGS. 1 and 2 were present are provided with the same reference numerals in FIG. 7. Thus, the device according to FIG. 7 has a chassis frame. which in this case, however, consists of a horizontal frame structure Γ and a standing frame structure I ″ and an arm 13 ′ for the handle 13

♦ o is provided. At the front end of the device are on the common axis 3 again two wheels 2 arranged. The generator is on the chassis frame 5. the vacuum pump 6, the detector 10, the control and display device 14 and the suction cup 15 assembled. In this embodiment, however, the base frame 1 'is additionally provided with a S ^ ornrad 30 provided, the vertical Tragschait 32 is vertically adjustable in a lifting device 31, so that you lift the suction cup 15 from the surface by extending the star wheel 30 downwards and by retracting the star wheel 30 can put the suction cup back against the surface.

A special arrangement option for the suction cup - which is also in accordance with the embodiment F i g. 1 and 2 is applicable - is also in F i g. 7 shown. Thereafter, the suction cup 15 is attached to a vertical shaft 33 which is in a Lifting device .34 is vertically adjustable In this way you can face the suction cup itself raise and lower the chassis frame vertically.

The suction line 4 of the vacuum pump 6 is shown in FIG. 7 indicated only by a dashed line The same applies to the pressure line ?, the funnel8 and the suction line 9 of the suction pump (not shown).

An additional arrangement for a further suction cup is shown in Figure 7, it can

however, in a corresponding modification also in the embodiment according to FIG. 1 and 2 are applied. Here, a hose drum 36, onto which a hose 37 is wound, is rotatably mounted on a base 35 on the chassis base frame 1 '. At the free end of this hose 37, another suction cup 15 a is attached. In the suction line 4 of the vacuum pump, a manually adjustable valve 18 is switched on, via which, depending on its setting • inmal ü ^h he einr line 39 of the suction cup 15 or another via a hose 40 and the hose 37 of the suction cup 15 a to the suction nozzle the vacuum pump 6 can be connected. t) The valve 21 ″ arranged in the suction nozzle 4 of the vacuum pump 6 is also operated here by means of an operating handle 18 on the handle 13 via a Bowden cable 19.

Due to the arrangement of the height-adjustable

The star wheel 30 is in the embodiment according to FIG. 7 the placing and lifting of the suction cup 15 relieved.

The additionally provided suction cup 15 a can be used by the operator to at places to carry out a gas pumping that cannot be driven on with the device shown. at such places are, for example, the branch lines in front gardens and the - especially

ίο leak-prone - points of passage of these branch lines in a building.

To avoid interference from the exhaust gases of the generator or from gasoline vapors, The gases that emerge from the carburetor are directed upwards by means of a chimney and well-sealed lines to the top, or the motor of the vacuum pump is fed from a car battery.

1 sheet of drawings

Claims (5)

t 919 claims: 1. Device for gas leak detection on buried ones Gas supply networks, with a suction cup that can be placed on the surface of the earth, which over a suction line is connected to a suction pump, which draws in an air sample and this one Flame ionization detector, which the air sample for the presence of a for the relevant gas typical constituent examined, characterized by the combination of the characteristics that a) the suction cup (15) has at least one that can be brought into engagement in an airtight manner with the surface of the earth Has edge web (16, 17), b) the suction pump is a vacuum pump (6) generating a negative pressure of about 0.8 at is and ao c) to the pressure line (7) of the vacuum pump a funnel (8) opening into the free atmosphere is attached, within which the inlet opening of the suction line (9) is a small one feeding the detector (10) Suction pump (11) is arranged. 2. Apparatus according to claim 1, characterized in that the suction cup (15) three concentrically has edge webs (16, 16 ', 16 ") which are arranged in relation to one another. 3. Apparatus according to claim 1 or 2, characterized in that that the lower dents of the edge webs (16) are made of a soft elastic seal (IG «) exist. 4. Apparatus according to claim 1, characterized in that the edge web (17) consists of metal and a blade-like lower edge (17 a) having. 5. Apparatus according to claim 4, characterized in that the edge web (17) on its Outside and / or inside at a distance from its lower edge (17 a) with a protruding, soft elastic sealing ring (42) is provided. 45