GB1577987A

GB1577987A - Inspection chambers

Info

Publication number: GB1577987A
Application number: GB2439679A
Authority: GB
Original assignee: Wavin BV
Current assignee: Wavin BV
Priority date: 1978-04-03
Filing date: 1978-04-03
Publication date: 1980-10-29

Description

(54) IMPROVEMENTS IN OR RELATING TO INSPECTION CHAMBERS (71) We, WAVIN B.V., a Dutch Body Corporate of 251 Handellaan, Zwolle, Holland, do hereby declare the invention for which we pray that a patent may be granted to us, and the mehod by which it is to be performed to be particularly described in and by the following statement: This invention is concerned with improvements relating to inspection chambers.

The invention includes an inspection chamber base of plastics material having an upwardly open main channel extending between an inlet opening thereto and an outlet opening therefrom, a group of at least two upwardly open branch channels extending from respective inlet openings thereto to one side of the main channel, and obturating means removably securable over at least one of said branch channels, which is/are not required in use, to prevent entry of solids thereinto.

The invention also includes an inspection chamber having a base as defined in the preceding paragraph.

The invention also includes an inspection chamber comprising a base as defined in the paragraph preceding the last above paragraph and an extension shaft fitted thereto to extend upwardly from an upper rim of the base.

In order that the invention may be better understood, an embodiment thereof, which is given by way of example only, will now be described, reference being had to the accompanying drawings, in which: Figure 1 is a top plan view of an inspection chamber base; Figures 2, 3 and 4 are respectively views taken in the direction of arrows II and III and along line IV-IV of Figure 1; Figure 5 is an axial section of an extension shaft for the base; Figure 6 is a part top plan view of the base with an obturating member fitted thereto; Figures 7 and 8 are respectively views taken in the direction of the arrow VII and along the line VIII-VIII in Figure 6; Figure 9 is a side view, to a larger scale than the previous figures, of a blanking plug; Figure 10 shows a connecting portion of the obturating member; and Figure 11 illustrates a connection between the plug and the connecting portion, and is a view taken in a direction corresponding to that indicated by arrow XI in Figure 10.

Figures 1 to 4 show an inspection chamber base 1 which is injection moulded as a one-piece unit in plastics material which may be reinforced. Although the base could form part of a one-piece chamber it is proposed that it should have one or more extension shafts 2 (Figure 5) fitted to it to build it up to a desired height. The inspection chamber is used in drainage or sewerage systems where one or more branch pipes connect with a main pipe. The chamber base has an upwardly open main channel 3 extending between an inlet opening 4 thereto and an outlet opening 5 therefrom, and a respective group of two upwardly open branch channels 6 extending to each side of the main channel 3 from respective inlet openings 7.The inlet and outlet openings 4, 5 and the inlet openings 7 are provided with pipe sockets 8 which extend radially outwardly of the wall 9 of the base and which enable connection of the base to the main and branch pipes (not shown). The main channel 3 falls from the inlet opening 4 to the outlet opening 5 (see Figures 3 and 4) so as to direct the flow from the inlet opening to the outlet opening, and the branch channels are arranged to direct the flow from their inlet openings 7 into the main channel in the flow direction therein.

A wall means 10 between the two branch channels 6 of each group provides side walls 11 of the channels 6 which extend higher than the opposed side walls 12 thereof to hinder cross-flow between the two branch channels. It will be understood that a group of branch channels 6 could comprise more than two branch channels and that in such a case respective wall means 10 may be provided between adjacent branch channels such that the side walls of the group of branch channels between the two outermost side walls thereof extend higher than those two outermost side walls to hinder crossflow between adjacent branch channels. In the illustrated embodiment the branch channels are substantially semi-circular in crosssection with the extended side walls 11 extending substantially tangentially upwardly.

The base has an upper rim having an annular tongue 13 for co-operation with a corresponding annular groove 14 of the extension shaft 2 (Figure 5) to enable the shaft 2 to be fitted on to the base 1 to extend the height thereof. At its end remote from the groove 14, the shaft, which like the base is formed of plastics material which may be reinforced, is provided with a tongue 15 to enable a similar shaft to be fitted thereto, or to provide a seating for a cover or cover frame. As illustrated, the shaft is provided with external, annular strengthening ribs 16.

Although, the base may be provided with a certain number of branch channels, a lesser number may be required in use. In such circumstances it is necessary to block off the inlet opening to any unused branch channel, but even so the presence of an unused branch channel presents an undesirable possibility of solids entering into that branch channel, for example during flooding of the chamber, and becoming lodged therein eventually to smell offensively. To avoid this possibility, we provide the illustrated base with a plastics obturating member 17 (Figures 6 to 8) which is constructed to fit over the branch channels of one group to prevent entry of solids thereinto. It will be understood that another obturating member, of mirror image to member 17, can be provided to fit over the other group of branch channels.The obturating member may be cut on-site if only one of the branch channels is not to be used. Alternatively a separate obturating member could be provided for each branch channel. In any event, the obturating member to be fitted is removably securable over at least one of the branch channels and extends over and is located by the wall means 10.

As shown in Figures 6 to 8, the obturating member 17 extends over all of the sectors of the base on one side of the main channel 3 and provides inclined faces 18 for directing material down into the main channel, a rib 19 locatable on the wall means 10, and projections 20 depending from the faces 18 and corresponding to the cross-sections of the bases of the branch channels at their entry point to the main channel. The member 17 is removably secured over the branch channels 6 by means of a releasable connection between the member 17 and a blocking plug 21 inserted in each of the sockets 8 of the inlet openings 7 of the unused branch channels as will now be described with reference to Figures 9 to 11.A plastics blanking plug 21 is inserted into each socket 8 of the inlet openings of the unused branch channels from the outside of the base until a flange 22 on the plug abuts the rim of the socket and prevents further insertion of the plug thereinto. The plug seals the inlet opening and is provided with a projection 23 engageable with a keyhole slot 24 in a web 25 of the member 17 to form therewith a releasable connection between the plug 21 and the member 17. As illustrated in Figure 11, the slot 24 locates in a neck portion of the projection 23 and the connection as well as securing the member in position prevents movement of the plug 21 out of the socket 8.

As will be appreciated the member 17 is provided with a respective web 25 corresponding to each branch channel inlet opening position, and that if both branch channels of a group were not required both inlet opening sockets 8 would be provided with a respective blanking plug 21 which would be releasably connected in the manner described above to a respective web of the member 17.

Attention is directed to the claims of the complete specification of our copending Application No.12991/78 (Serial No.

1577986) from which the present application is divided.

WHAT WE CLAIM IS: 1. An inspection chamber base of plastics material having an upwardly open main channel extending between an inlet opening thereto and an outlet opening therefrom, a group of at least two upwardly open branch channels extending from respective inlet openings thereto to one side of the main channel, and obturating means removably securable over at least one of said branch channels, which is/are not required in use, to prevent entry of solids thereinto.

2. An inspection chamber base as claimed in claim 1, wherein said obturating means extend over and is located by wall means between adjacent branch channels of said group.

3. An inspection chamber base as claimed in claim 1 or 2, wherein said obturating means is removably securable over said at least one branch channel by means of releasable connection means on said obturating means and a blanking plug insertable in the or each respective branch channel inlet from the outside of said base.

4. In inspection chamber base as

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Claims

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hinder cross-flow between the two branch channels. It will be understood that a group of branch channels 6 could comprise more than two branch channels and that in such a case respective wall means 10 may be provided between adjacent branch channels such that the side walls of the group of branch channels between the two outermost side walls thereof extend higher than those two outermost side walls to hinder crossflow between adjacent branch channels. In the illustrated embodiment the branch channels are substantially semi-circular in crosssection with the extended side walls 11 extending substantially tangentially upwardly.

The base has an upper rim having an annular tongue 13 for co-operation with a corresponding annular groove 14 of the extension shaft 2 (Figure 5) to enable the shaft 2 to be fitted on to the base 1 to extend the height thereof. At its end remote from the groove 14, the shaft, which like the base is formed of plastics material which may be reinforced, is provided with a tongue 15 to enable a similar shaft to be fitted thereto, or to provide a seating for a cover or cover frame. As illustrated, the shaft is provided with external, annular strengthening ribs 16.

Although, the base may be provided with a certain number of branch channels, a lesser number may be required in use. In such circumstances it is necessary to block off the inlet opening to any unused branch channel, but even so the presence of an unused branch channel presents an undesirable possibility of solids entering into that branch channel, for example during flooding of the chamber, and becoming lodged therein eventually to smell offensively. To avoid this possibility, we provide the illustrated base with a plastics obturating member 17 (Figures 6 to 8) which is constructed to fit over the branch channels of one group to prevent entry of solids thereinto. It will be understood that another obturating member, of mirror image to member 17, can be provided to fit over the other group of branch channels.The obturating member may be cut on-site if only one of the branch channels is not to be used. Alternatively a separate obturating member could be provided for each branch channel. In any event, the obturating member to be fitted is removably securable over at least one of the branch channels and extends over and is located by the wall means 10.

As shown in Figures 6 to 8, the obturating member 17 extends over all of the sectors of the base on one side of the main channel 3 and provides inclined faces 18 for directing material down into the main channel, a rib 19 locatable on the wall means 10, and projections 20 depending from the faces 18 and corresponding to the cross-sections of the bases of the branch channels at their entry point to the main channel. The member 17 is removably secured over the branch channels 6 by means of a releasable connection between the member 17 and a blocking plug 21 inserted in each of the sockets 8 of the inlet openings 7 of the unused branch channels as will now be described with reference to Figures 9 to 11.A plastics blanking plug 21 is inserted into each socket 8 of the inlet openings of the unused branch channels from the outside of the base until a flange 22 on the plug abuts the rim of the socket and prevents further insertion of the plug thereinto. The plug seals the inlet opening and is provided with a projection 23 engageable with a keyhole slot 24 in a web 25 of the member 17 to form therewith a releasable connection between the plug 21 and the member 17. As illustrated in Figure 11, the slot 24 locates in a neck portion of the projection 23 and the connection as well as securing the member in position prevents movement of the plug 21 out of the socket 8.

As will be appreciated the member 17 is provided with a respective web 25 corresponding to each branch channel inlet opening position, and that if both branch channels of a group were not required both inlet opening sockets 8 would be provided with a respective blanking plug 21 which would be releasably connected in the manner described above to a respective web of the member 17.

Attention is directed to the claims of the complete specification of our copending Application No.12991/78 (Serial No.

1577986) from which the present application is divided.

WHAT WE CLAIM IS: 1. An inspection chamber base of plastics material having an upwardly open main channel extending between an inlet opening thereto and an outlet opening therefrom, a group of at least two upwardly open branch channels extending from respective inlet openings thereto to one side of the main channel, and obturating means removably securable over at least one of said branch channels, which is/are not required in use, to prevent entry of solids thereinto.
2. An inspection chamber base as claimed in claim 1, wherein said obturating means extend over and is located by wall means between adjacent branch channels of said group.
3. An inspection chamber base as claimed in claim 1 or 2, wherein said obturating means is removably securable over said at least one branch channel by means of releasable connection means on said obturating means and a blanking plug insertable in the or each respective branch channel inlet from the outside of said base.
4. In inspection chamber base as

claimed in claim 3, wherein said releasable connection comprises slot means on said obturating means and projection means on the or each blanking plug.
5. An inspection chamber having a base as claimed in any one of the preceding claims.
6. An inspection chamber comprising a base as claimed in any one of the preceding claims and an extension shaft fitted thereto to extend upwardly from an upper rim of the base.
7. An inspection chamber as claimed in claim 6, wherein said extension shaft engages said upper rim of the base by means of a tongue and groove arrangement.
8. An inspection chamber base as claimed in claim 1, wherein said obturating means is constructed and securable substantially as herein described with reference to Figures 6 to 11 of the accompanying drawings.