GB1577454A

GB1577454A - Inspection chamber assembly for buried drainage systems

Info

Publication number: GB1577454A
Application number: GB46884/77A
Authority: GB
Original assignee: Marley Extrusions Ltd
Current assignee: DHM Plastics Ltd
Priority date: 1977-11-10
Filing date: 1977-11-10
Publication date: 1980-10-22
Also published as: AU4099378A; DE2848498A1; NZ188871A; ZA786011B; FR2408694B1; FR2408694A1; DE2848498C2

Description

(54) INSPECTION CHAMBER ASSEMBLY FOR BURIED DRAINAGE SYSTEMS (71) We, MARLEY EXTRUSIONS LIMITED, a British Company, of Lenham, Maidstone, Kent, England, 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: This invention relates to inspection chambers for allowing access from ground level to buried drainage systems.

Conventional inspection chambers have an open channel at the bottom thereof into and out of which drainpipes carry sewage, waste water or rainwater. However it has been found that such an open channel tends to produce blockages at the entrance to drainpipes leading away therefrom. This is because an object having substantially the diameter of the drainpipe can be carried down a dranpipe to the open channel, forced along by the flow of liquid. Such an object may then swell when it reaches the open channel, and so be unable to enter the pipes leading away from the inspection chamber and thus cause a blockage. It is thus desirable to provide means of access to underground drains in which the pipe remains closed and in which full pipe dimensions are maintained in order to reduce the likelihood of a blockage occuring.However, in conventional inspection chambers having closed pipe systems, it is necessary to be able to disengage a plug or other member forming part of the pipe system at the bottom of the inspection chamber in order to carry out an inspection or maintenance.

This is however undesirable, particularly in the case when a blockage has occurred, and contaminated water under pressure is present in the drains, in view of the risk of overflow of the contaminated water when the pressure is released.

According to the invention, there is provided an inspection chamber assembly for buried drainage systems comprising a pipe fitting including a lower portion of at least one drainpipe, a plug including the remainder of the or each drainpipe, means defining an inspection chamber, a seal for sealing the plug either to the pipe fitting or to said means defining an inspection chamber a manhole cover mountable at the top of the inspection chamber when the assembly is installed, and a rigid member extending from the underside of the manhole cover to the plug, and fixed to the plug.

The inspection chamber assembly according to the invention thus comprises a closed pipe system comprising the pipe fitting and the plug which, nevertheless, can be opened from the surface by removing the manhole cover and withdrawing the rigid member to which the plug is attached.

It is desirable for the manhole cover merely to rest on the rim of the inspection chamber, rather than being screwed or otherwise locked in position. In this way if pressures develop in the drainpipes in excess of the normal working pressures the manhole cover will be lifted by the rigid member. This will prevent sewage, etc. being forced up the drainpipes against the desired direction of flow under storm conditions. To provide the desired mass, the cover can be made of metal or concrete.

Owing to the fact that the plug is sealed either to the means defining the inspection chamber or the pipe fitting at the bottom of the inspection chamber, under normal conditions, the sewage, etc., cannot enter the inspection chamber. This is desirable to prevent accumulations of material in the inspection chamber. A further advantage of the invention arises from the fact that no rotary movement is necessary to remove the plug from the pipe fitting. Such rotary movement could well prove impossible if the pipe were blocked The various parts of the inspection cham ber assembly are preferably made of a plastics material. In this case, the rigid member can take the form of a rod or tube which can be solvent cemented to the plug.

In addition, the pipe fitting can be solvent cemented to the means defining the inspection chamber assembly.

The plug is preferably located with respect to the pipe fitting by one or more locating means. These can, for example, take the form of recesses provided on either the plug or the pipe fitting adapted to receive protruding members on the pipe fitting or the plug respectively.

The inspection chamber assembly of the invention can be adapted to any configuration of drainpipes by the use of a suitable plug and pipe fitting.

In the accompanylng drawings: Figure 1 is a section through an embodiment of an inspection chamber assembly according to the invention suitable for allowing access to a straight drainpipe and, Figure 2 is a section through a second embodiment of an inspection chamber assembly according to the invention, suitable for allowing access to a junction between two drainpipes, meeting at an angle of 45 .

As shown in Figure 1, an inspection chamber assembly comprises a pipe fitting 1 which includes the lower half of a drainpipe 2 and comprises a portion 3 which extends upwardly to form a circular rim. A plug 4 forms the remaining or upper half of the drainpipe 2, and includes an upwardly extending portion 5 concentric with the portion 3 of the pipe fitting. An inspection chamber 6 is defined by a cylindrical member 7, a manhole cover supporting member 8 which is itself cemented to the rim of the member 7, a connecting member 9. The connecting member 9 is secured to the rim of portion 3 of the pipe fitting 1 and is sealed to the portion 5 of the plug 4 by means of an O-ring seal 10. The member 9 is sealed to the member 7 by a further seal 11. The inspection chamber is closed by a manhole cover 12.A rigid tube 13 extends from the underside of the manhole cover 12 to the plug 4, and is fixed to the plug 4.

Thus, when it is desired to inspect the drainpipe 2, the cover 12 is removed and the tube 13 pulled upwardly, bringing with it the plug 4 and the O-ring seal 10 which is a tight fit on the plug 4. In this manner, the drainpipe can be inspected without the necessity of any work being carried out at the bottom of the inspection chamber and without rotation of any parts.

In the embodiment of Figure 2 identical members have been given the same reference numerals as in Figure 1 and will not be further described. A pipe fitting 22 includes the lower part of two drainpipes of equal diameter meeting at angle of 45". A plug 24 defines the remaining portion of the two pipes. The design of these parts is such that the remainder of the inspection chamber assembly is identical to that of Figure 1. The rigid tube 13 will be secured to plug 24 in the same manner, and the plug 24 is sealed to the member 9 in an identical fashion.

It will thus be appreciated that the present invention can be applied to any configuration of drainpipes which may be required.

The drainpipes can be of the same or different diameters.

WHAT WE CLAIM IS: 1. An inspection chamber assembly for buried drainage systems comprising a pipe fitting including a lower portion of at least one drainpipe, a plug including the remainder of the or each drainpipe, means defining an inspection chamber, a seal for sealing the plug either to the pipe fitting or to said means defining an inspection chamber, a manhole cover mountable at the top of the inspection chamber when the assembly is installed, and a rigid member extending from the underside of the manhole cover to the plug, and fixed to the plug.

2. An inspection chamber assembly as claimed in claim 1 wherein said manhole cover rests on said means defining an inspection chamber so that excess pressures above normal working pressure will tend to lift the manhole cover.

3. An inspection chamber assembly as claimed in 1 or 2 wherein said pipe fitting forms at least the lower half of the or each drainpipe.

4. An inspection chamber assembly as claimed in any preceding claim wherein said plug and said rigid member are made of a plastics material and are fixed to one another by solvent cementing.

5. An inspection chamber assembly as claimed in any preceding claim, wherein said plug includes a portion surrounding one end of said rigid member.

6. An inspection chamber assembly substantially as herein described in either of the Figures of the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ber assembly are preferably made of a plastics material. In this case, the rigid member can take the form of a rod or tube which can be solvent cemented to the plug. In addition, the pipe fitting can be solvent cemented to the means defining the inspection chamber assembly. The plug is preferably located with respect to the pipe fitting by one or more locating means. These can, for example, take the form of recesses provided on either the plug or the pipe fitting adapted to receive protruding members on the pipe fitting or the plug respectively. The inspection chamber assembly of the invention can be adapted to any configuration of drainpipes by the use of a suitable plug and pipe fitting. In the accompanylng drawings: Figure 1 is a section through an embodiment of an inspection chamber assembly according to the invention suitable for allowing access to a straight drainpipe and, Figure 2 is a section through a second embodiment of an inspection chamber assembly according to the invention, suitable for allowing access to a junction between two drainpipes, meeting at an angle of 45 . As shown in Figure 1, an inspection chamber assembly comprises a pipe fitting 1 which includes the lower half of a drainpipe 2 and comprises a portion 3 which extends upwardly to form a circular rim. A plug 4 forms the remaining or upper half of the drainpipe 2, and includes an upwardly extending portion 5 concentric with the portion 3 of the pipe fitting. An inspection chamber 6 is defined by a cylindrical member 7, a manhole cover supporting member 8 which is itself cemented to the rim of the member 7, a connecting member 9. The connecting member 9 is secured to the rim of portion 3 of the pipe fitting 1 and is sealed to the portion 5 of the plug 4 by means of an O-ring seal 10. The member 9 is sealed to the member 7 by a further seal 11. The inspection chamber is closed by a manhole cover 12.A rigid tube 13 extends from the underside of the manhole cover 12 to the plug 4, and is fixed to the plug 4. Thus, when it is desired to inspect the drainpipe 2, the cover 12 is removed and the tube 13 pulled upwardly, bringing with it the plug 4 and the O-ring seal 10 which is a tight fit on the plug 4. In this manner, the drainpipe can be inspected without the necessity of any work being carried out at the bottom of the inspection chamber and without rotation of any parts. In the embodiment of Figure 2 identical members have been given the same reference numerals as in Figure 1 and will not be further described. A pipe fitting 22 includes the lower part of two drainpipes of equal diameter meeting at angle of 45". A plug 24 defines the remaining portion of the two pipes. The design of these parts is such that the remainder of the inspection chamber assembly is identical to that of Figure 1. The rigid tube 13 will be secured to plug 24 in the same manner, and the plug 24 is sealed to the member 9 in an identical fashion. It will thus be appreciated that the present invention can be applied to any configuration of drainpipes which may be required. The drainpipes can be of the same or different diameters. WHAT WE CLAIM IS:

1. An inspection chamber assembly for buried drainage systems comprising a pipe fitting including a lower portion of at least one drainpipe, a plug including the remainder of the or each drainpipe, means defining an inspection chamber, a seal for sealing the plug either to the pipe fitting or to said means defining an inspection chamber, a manhole cover mountable at the top of the inspection chamber when the assembly is installed, and a rigid member extending from the underside of the manhole cover to the plug, and fixed to the plug.