GB1588421A - Checking a connection in an at least partly gas-filled piping system - Google Patents

Description

(54) CHECKING A CONNECTION IN AN AT LEAST PARTLY GAS-FILLED PIPING SYSTEM (71) We, DHV RAADGEVEND INGENIE URSBUREAU BV, a Dutch body corporate, of 35 Laan 1914, 3800 AB Amersfoort, Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a method of checking a connection in an at least partly gas-filled piping system.

In piping systems, such as sewerage systems, it is of major importance to be able to ascertain simply and quickly whether all connections ar properly fitted and are functioning adequately.

In practice, connections are frequency found to be missing or to be improperly fitted, which applies both to mixed sewerage systems, where rain water and waste liquids are conveyed in the same sewer pipes, and to separate sewage systems, where the rain water and the waste liquids are collected and conveyed separately.

In a separate sewerage system, a connection may have been made erroneously from a pipe for waste liquids to a rain-water pipe, thus causing the quality of the water in the rain-water sewerage system to deteriorate.

Conversely, there is the possibility of a rainwater pipe being mistakenly connected to a pipe for waste liquids, as a result of which the hydraulic load on the sewerage system for waste liquids is unintentionally increased.

Furthermore, the piping system can become obstructed in such a way that the communication between different piping elements is interrupted in whole or in part.

According to a known method, use is made of a tracer in detecting erroneous or missing connections, or obstructions, in a piping system. However, this prior-art method is time-consuming and expensive. What is desired is a method of checking whether a connection in an at least partly gas-filled piping system connects two predetermined pipe sections, which method can be carried out quickly and simply, and which is considerably less expensive than the known method.

In a method according to the invention a transmitter is arranged in or near a piping section on one side of the connection to be checked and delivers acoustic vibrations of a predetermined frequency and amplitude into this piping section, a receiver which is sensitive to these acoustic vibrations being arranged in or near a piping section on the other side of the connection to be checked the intensity of reception serving to indicate the presence or the quality of the connection to be checked.

The fact whether the acoustic signal delivered by the transmitter is received or not, or the degree of intensity of the reception thereof, allows one to deduce whether a connection has indeed been provided, or whether there is a possible obstruction between the predetermined pipe sections of the piping system. The checking operations can be performed very rapidly, simply and inexpensively, since they only require the transmitter and the receiver to be arranged at points which are suitable for this purpose.

Since the acoustic vibrations can travel appreciable distances, it is furthermore possible to inspect a large number of connections with the transmitter, or the receiver, remaining arranged at a fixed point.

In order to bridge a large distance with the acoustic signal, it is naturally necessary, in view of the energy losses that occur, to use a relatively high-power source of acoustic vibrations.

The afore-mentioned sections of the piping system on either side of the connection to be checked should nowhere be entirely filled with liquid between the transmitter and the receiver. The maximum bridgeable distance of the acoustic signals being longer the less liquid there is in the piping sections to be traversed by these signals, it is naturally an advantage if the load of liquid in these piping sections is as low as possible.

If piping sections are to be inspected which are filled entirely with liquid when in operation, such inspection is preferably carried out prior to the system being made operational, since it will otherwise be necessary to empty, at least in part, the piping sections which are to be checked.

Sewerage systems, at least in relatively dry atmospheric conditions, will generally not show a high degree of liquid filling, so that it will frequently be possible to carry out the checking operations without interrupting normal service conditions.

In checking pipes in buildings, it will naturally be necessary first to drain the goose necks, since they would otherwise be impermeable to the acoustic vibrations.

If there is a flow of gas in the pipework, it is preferable for the receiver to be arranged downstream from the transmitter.

It is furthermore possible to induce in the piping system a gas current which is directed from the piping section with which the transmitter is associate towards the piping section with which the receiver is associated.

With advantage use can be made of a transmitter which is designed to deliver acoustic vibrations of a high frequency, in particular acoustic vibrations beyond the limit of audibility. When using high-frequency acoustic vibrations, the energy losses resulting from acoustic resistances-such as bends, branches, constrictions and the like in the piping sections to be traversed-are small, while identification by the receiver is facilitated. If the acustic vibrations are beyond the limit of audibility, any nuisance of noise caused to the environment is effectively prevented.

Since the energy Ics;es of acoustic vibrations are at a minimum when propagating in a space which expands in the direction of propagation, it is advisable to arrange the transmitter in or near the piping section which has the smaller cross-section of the two afore -mentioned piping sections. In checking the connection of pipes from houses to a sewerage system, for example, it will be advantageous to arrange the transmitter in or near the pipe involved, and the receiver in or near the sewer pipe concerned.

In order to prevent energy losses as far as possible, and to enlarge- the maximum distance which can be bridged by the acoustic -signal, the piping section with which the transmitter is associated can be shut off on the side facing away from the connection to be checked. It is also possible to shut off any -branch pipes of the two afore-mentioned -sections of the piping system with- respect to said sections.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 schematically illustrates the inspect of the connections of the piping system of a residential house which is connected to a separate sewerage system; Figure 2 is a sectional view of an acoustic transmitter; and Figures 3 and 4 are sectional views of the upper part of a pit in which a receiver is accommodated.

In checking the connection 1 of a pipe section- 3 for waste liquids of the residential house to the sewerage system 3 for waste liquids, a transmitter 4, with which acoustic vibrations having a predetermined frequency and amplitude can be delivered, can be arrangedin or near the man hole 5 concerned, while a receiver 7 which is sensitive to these acoustic vibrations is arranged in or near the inspection pit 6 belonging to the sewerage system -4 for waste liquids, the intensity of reception serving to indicate the presence or the quality of the connection 1.

Similarly, checking of the connection 11 of a rain-water conduit 21 of the house to the rain-water sewerage system 31 can be carried out by arranging the transmitter 4 in or near the man hole 51 concerned, and the receiver 7 in or near the inspection pit 61 concerned.

Since the man holes 5, 51 are outside the building, these inspections can be carried out independently of the house owner.

In checking the connections 8 of the pipes 9 of bathroom and other plumbing fixtures to the pipe-section 2 for waste liquids, and the connections 81 of the pipes 91 to the rainwater conduit 2l,the receiver 7 can be arranged in or near the proper man hole 5, 51, whereupon all pipes 9, 91 can be checked with the transmitter 4. Of course, it is also possible to arrange the tranmitter 4 instead of the receiver 7 in or near the proper man hole 5, 51, in which case the pipes 9, 91 are submitted to an inspection with the aid of the receiver 7. Preferably, however, the transmitter 4 is always arranged in or near a piping section having a smaller cross-section than that in or near which the receiver 7 is arranged.

Figure 2 shows an embodiment of the transmitter 4. This transmitter 4 comprises a casing 10 in which a source of acoustic vibrations 11 is accommodated and which is provided at an open end with a flange 12.

A mounting flange 13 is fastened to this flange 12, for example by means of bolts (not shown), and a flexible tube 15 is attached to this mounting flange 13 with the aid of a hose clamp 14. The flexibility of this tube 15 allows an acoustic signal to be introduced into a piping section even in places which are difficult to reach.

In general, the receiver 7 with accessories for transmitting the signal to the side of the street is placed above the opening of the inspection pit our the man hole after its cover has been removed, so as to allow the acoustic vibrations delivered by the transmitter 4 to be collected. This, however, requires the street to be closed in part, which is not always practicable in view of the traffic.

Therefore, an inspection may be carried out by replacing the existing cover of a pit, such as an inspection pit or a man hole temporarily by a special cover 16 (Figure 3), underneath which a receiver 7 with accessories is mounted. In the drawing, also the transmitter 29 of a transmitting and receiving set is mounted underneath the pit cover. This cover 16 can be manufactured, for example, of a lightweight material, such as aluminium.

Since such a cover does not possess the required minimum weight, anchoring bolts 17 are fitted with which this cover 16 can be detachably connected to the pit cover ring 18.

If prevailing circumstances make it impossible to anchor the cover 16 as shown in Figure 3 on a man hole or on an inspection pit, the receiver 7 with accessories can be connected to a clamping device 19 which allows detachable mounting in the man hole or the inspection pit, preferably in the ring 18 of the pit cover.

In the embodiment shown schematically in Figure 4, a receiver 7 with accessories is fitted underneath a cone 20 upon which an upright stud bolt 21 is mounted. A sleeve 22, slidably mounted on this stud bolt 21, supports by means of connecting plates 23 three horizontal guide sleeves 24 which enclose angles of 1200 with each other and in which rods 25 are slidably mounted. These rods 25 have projection 26 at their inner end which can come into contact with the cone 20, while the outer end of the rods 25 is provided with a rubber foot 27. A nut 28 is screwed on the part of the stud bolt 21 which projects outside the sleeve 22. Tightening of this nut 28 causes the rods 25 to be displaced outwardly and their foot 27 to come into clamping contact with the wall of the ring 18 of the pit cover (or with the pit wall).

When the inspection has been completed, the clamping device 19 can be loosened unscrewing the nut 28, whereupon the receiver 7 with accessories can be removed from the pit.

WHAT WE CLAIM IS:- 1. A method of checking whether a connection in an at least partly gas-filled piping system connects two predetermined pipe sections, in which a transmitter is arranged in or near the piping section on one side of the connection to be checked and delivers acoustic vibrations of a predetermined frequency and amplitude into this piping section, a receiver which is sensitive to these acoustic vibrations being arranged in or near the piping section on the other side of the connection to be checked, the intensity of reception serving to indicate the presence or the quality of the connection to be checked.

2. A method as claimed in claim 1, with a gas flow prevailing in the piping system, in which the receiver is arranged downstream from the transmitter.

3. A method as claimed in claim 1, in which a gas current is induced in the piping system which is directed from the piping section with which the transmitter is associated towards the piping section with which the receiver is associated.

4. A method as claimed in any of the preceding claims, in which the transmitter is arranged in or near the piping section which has the smaller cross-section of the two aforementioned piping sections.

5. A method as claimed in any of the preceding claims, in which the piping section with which the transmitter is associated is shut off on the side facing away from the connection to be checked.

6. A method as claimed in any of the preceding claims, in which any branch pipes of the two afore-mentioned piping sections are shut off with respect to the said piping sections.

7. A method as claimed in any of the preceding claims, in which the transmitter comprises a casing which accommodates a source of acoustic vibrations and which has an open end to which a flexible tube is connected.

8. A method as claimed in any of the preceding claims, in which the receiver is fitted underneath a cover for a pit, such as an inspection pit or a man hole.

9. A method as claimed in claim 8, in which the cover is made of aluminium.

10. A method as claimed-in claim 8 or 9, in which the cover is provided with anchorages for anchoring it in position upon the pit.

11. A method of checking a connection in an at least partly gas-filled sewage system, substantially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. street to be closed in part, which is not always practicable in view of the traffic. Therefore, an inspection may be carried out by replacing the existing cover of a pit, such as an inspection pit or a man hole temporarily by a special cover 16 (Figure 3), underneath which a receiver 7 with accessories is mounted. In the drawing, also the transmitter 29 of a transmitting and receiving set is mounted underneath the pit cover. This cover 16 can be manufactured, for example, of a lightweight material, such as aluminium. Since such a cover does not possess the required minimum weight, anchoring bolts 17 are fitted with which this cover 16 can be detachably connected to the pit cover ring 18. If prevailing circumstances make it impossible to anchor the cover 16 as shown in Figure 3 on a man hole or on an inspection pit, the receiver 7 with accessories can be connected to a clamping device 19 which allows detachable mounting in the man hole or the inspection pit, preferably in the ring 18 of the pit cover. In the embodiment shown schematically in Figure 4, a receiver 7 with accessories is fitted underneath a cone 20 upon which an upright stud bolt 21 is mounted. A sleeve 22, slidably mounted on this stud bolt 21, supports by means of connecting plates 23 three horizontal guide sleeves 24 which enclose angles of 1200 with each other and in which rods 25 are slidably mounted. These rods 25 have projection 26 at their inner end which can come into contact with the cone 20, while the outer end of the rods 25 is provided with a rubber foot 27. A nut 28 is screwed on the part of the stud bolt 21 which projects outside the sleeve 22. Tightening of this nut 28 causes the rods 25 to be displaced outwardly and their foot 27 to come into clamping contact with the wall of the ring 18 of the pit cover (or with the pit wall). When the inspection has been completed, the clamping device 19 can be loosened unscrewing the nut 28, whereupon the receiver 7 with accessories can be removed from the pit. WHAT WE CLAIM IS:-

1. A method of checking whether a connection in an at least partly gas-filled piping system connects two predetermined pipe sections, in which a transmitter is arranged in or near the piping section on one side of the connection to be checked and delivers acoustic vibrations of a predetermined frequency and amplitude into this piping section, a receiver which is sensitive to these acoustic vibrations being arranged in or near the piping section on the other side of the connection to be checked, the intensity of reception serving to indicate the presence or the quality of the connection to be checked.

2. A method as claimed in claim 1, with a gas flow prevailing in the piping system, in which the receiver is arranged downstream from the transmitter.

3. A method as claimed in claim 1, in which a gas current is induced in the piping system which is directed from the piping section with which the transmitter is associated towards the piping section with which the receiver is associated.

4. A method as claimed in any of the preceding claims, in which the transmitter is arranged in or near the piping section which has the smaller cross-section of the two aforementioned piping sections.

5. A method as claimed in any of the preceding claims, in which the piping section with which the transmitter is associated is shut off on the side facing away from the connection to be checked.

6. A method as claimed in any of the preceding claims, in which any branch pipes of the two afore-mentioned piping sections are shut off with respect to the said piping sections.

7. A method as claimed in any of the preceding claims, in which the transmitter comprises a casing which accommodates a source of acoustic vibrations and which has an open end to which a flexible tube is connected.

8. A method as claimed in any of the preceding claims, in which the receiver is fitted underneath a cover for a pit, such as an inspection pit or a man hole.

9. A method as claimed in claim 8, in which the cover is made of aluminium.

10. A method as claimed-in claim 8 or 9, in which the cover is provided with anchorages for anchoring it in position upon the pit.

11. A method of checking a connection in an at least partly gas-filled sewage system, substantially as described herein with reference to the accompanying drawings.