JET NOZZLE FOR PROPELLING AN APPARATUS ALONG A CONDUIT AND APPARATUS PROVIDED WITH SUCH A JET NOZZLE

Abstract: A jet nozzle (18) for use in propelling a trolley or sledge (10) provided with a television or video camera (15) along a conduit, such as a sewer, for use in inspecting the interior of the conduit, the jet nozzle (18) comprising a casing (20) having an end wall (21) provided with a plurality of discharge openings (22) communicating with a chamber (25) formed between said end wall (21) and a transverse wall (24), an inlet (23) in communication with the chamber (25) and connected to a hose (19), a bearing (26) provided on the casing (20) mounting a connector member (28) for connecting the jet nozzle (18) to the trolley or sledge (10) and allowing the casing (20) to rotate relative to the connector member (28).

Description: This invention relates to a jet nozzle device for use in propelling an apparatus along a conduit and to an apparatus provided with such a device. Particularly, but not exclusively, the jet nozzle device is used for propelling a camera carrying apparatus along a conduit, such as a sewer, for use in inspecting the interior of the conduit. It is known to propel a television-camera-carrying apparatus along a sewer by means of a water jet nozzle device supplied with water under pressure through a hose, the jet nozzle device being connected to the hose by a rigid connector and connected to the camera carrying apparatus by a swivel pin connector. Such an arrangement corresponding to the preamble of claim 1 is disclosed in US-A-4,107,738. A disadvantage of the known jet nozzle device is that the swivel pin can jam due to debris, friction and/or wear and any torque applied to the hose can be applied to the camera-carrying apparatus causing it to tip or turn over. Another disadvantage of the known jet nozzle device is that the water jet is discharged at an angle and impinges on the internal surface of the sewer and under certain conditions can create a vacuum in the sewer upstream of the jet nozzle device, and any water in the conduit is disturbed by the vacuum and creates a mist or spray in front of the camera lens, thus preventing the camera from producing a clear picture of the interior of the conduit. According to the present invention in one aspect there is provided a jet nozzle device for use in propelling apparatus along a conduit, comprising a casing having a wall at one axial end provided with a plurality of discharge openings communicating with a chamber formed between said wall and a transverse wall spaced from said wall, an inlet in communication with said chamber, means for connecting a hose to said inlet, and a bearing interposed between the casing and the apparatus and comprising a connector member for connecting the jet nozzle device to said apparatus mounted by said bearing for rotation relative to the casing, characterised in that the bearing is disposed in or on the casing between the side of the transverse wall remote from the chamber and a radially outwardly-extending flange provided on the connector member, said connector member extending from the other end of said casing, and said flange extending suitably close to said other end to cooperate therewith in preventing debris from entering the bearing. A transverse outwardly-directed peripherally-extending deflector member may be provided on the casing or on the connector member. According to the present invention in another aspect there is provided a camera-carrying apparatus comprising a wheeled trolley or sledge provided with skids, a camera mounted on the trolley or sledge, and a jet nozzle device as recited above, connected by said connector member to the rear end of the trolley or sledge. An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side elevation of a camera-carrying apparatus provided with a jet nozzle device embodying the present invention, Figure 2 is a longitudinal section of the jet nozzle device, and Figure 3 is a rear view of the jet nozzle device taken in the direction of arrow 3 indicated on Figure 2. The apparatus shown in Figure 1 comprises a trolley 10 provided with wheels 11 mounted on a member 12 which is connected to the trolley 10 by hinged levers 13. Provided on the trolley 10 are axles 14. In order to reduce the height of the trolley 10 the member 12 and levers 13 can be disconnected from the trolley 10 and the wheels 11 mounted on the axles 14. Mounted on the trolley 10 is a television camera 15 whose lens face forwardly and the camera 15 is connected by a connector 16 to a cable 17 which at its other end is connected to a remote monitor (not shown), the cable 17 passing around a rotatable drum (not shown). Connected to the trolley 10 is a jet nozzle device 18 which has a hose 19 connected to it through which fluid under pressure is supplied to the jet nozzle device 18. The trolley 10 is propelled in the direction of the arrow shown in Figure 1. In use of the apparatus the trolley 10 is propelled along a conduit, such as a sewer, and the picture taken by the camera of the interior of the conduit is viewed on the monitor. The jet nozzle device 18 comprises a casing 20 having an end wall 21 provided with an annular array of discharge openings 22 and an inlet 23. Formed between the end wall 21 and a spaced transverse wall 24 is a chamber 25 in communication with the openings 22 and inlet 23. Provided within the casing 20 and located at the other side of the wall 24 is a thrust bearing 26. Received within the thrust bearing 26 is a circular part 27 of a connector member 28 having an axially extending flange 29 provided with a hole 30 through which can extend a pin 31 provided on the trolley 10. The connector member 28 is provided with a radially extending flange 32 which is close to the adjacent end of the casing 20 and prevents the ingress of debris into the bearing 26. The discharge openings 22 are axially extending. The inlet 23 is connected to the hose 19 by a connector 33. If in use of the apparatus any torque is applied to the hose 19 then the casing 20 will rotate relative to the connector member 28 through the bearing 26 and such torque will not be transmitted to the trolley. A removable or fixed flexible or rigid transverse outwardly-directed peripherally-extending deflector member 34 can be provided on the connector member 28. Alternatively, the deflector member 34 can be provided on the casing 20. If a vacuum is created in the conduit by the nozzle 18 the deflector member 34 prevents the vacuum acting on any water forwardly of the camera 15. The jet nozzle 18 is preferably supplied with water under pressure but alternatively, the jet nozzle 18 may be supplied with a gas, such as air, under pressure. The camera 15 may comprise a video camera if desired. By deflecting the propulsive fluid axially it does not impinge on the wall of the conduit and reduces the tendency of producing a vacuum upstream of the nozzle 18. Instead of the trolley 10 being provided with wheels 11 it can be provided with skids and thus comprise a sledge. The trolley 10 is provided with a bar or bars 35 which protect the camera 15 from damage should the trolley 10 turn over and during ascent or descent in a man-hole or other access to a drain or sewer. The bearing 26 may be provided on the exterior of the casing 20 and the bearing 26 may comprise a plain bearing, e.g. two surfaces in sliding contact with each other. The openings 22 may be inclined if desired. In an alternative arrangement the casing 20 may be detachable from the connector member 28 so as to be capable of being propelled along a conduit without being connected to the trolley 10 in order to clean the conduit.

Claims: A jet nozzle device (18) for use in propelling an apparatus along a conduit, comprising a casing (20) having a wall (21) at one axial end provided with a plurality of discharge openings (22) communicating with a chamber (25) formed between said wall (21) and a transverse wall (24) spaced from said wall (21), an inlet (23) in communication with said chamber (25), means (33) for connecting a hose (19) to said inlet (23), and a bearing (26) interposed between the casing and the apparatus and comprising a connector member (28) for connecting the jet nozzle device (18) to said apparatus mounted by said bearing (26) for rotation relative to the casing (20), characterised in that the bearing is disposed in or on the casing between the side of the transverse wall (24) remote from the chamber (25) and a radially outwardly-extending flange (32) provided on the connector member (28), said connector member extending from the other end of said casing, and said flange (32) extending suitably close to said other end to cooperate therewith in preventing debris from entering the bearing. A jet nozzle as claimed in claim 1, in which a transverse outwardly-directed peripherally-extending deflector member (34) is provided on the casing (20) or on the connector member (28). A jet nozzle as claimed in claim 1 or claim 2, in which the casing (20) is detachable from the connector member (28). A camera-carrying apparatus comprising a wheeled trolley or a sledge (10) provided with skids, a camera (15) mounted on the trolley or sledge (10), and a jet nozzle device as claimed in any preceding claim connected by said connector member (28) to the rear end of the trolley or sledge (10). Apparatus as claimed in claim 4, in which the wheels (11) of the trolley (10) are mounted on a member (12) connected to the trolley (10) by hinged levers (13). Apparatus as claimed in claim 5, in which the trolley (10) is provided with axles (14) on which the wheels (11) can be mounted when the member (12) and levers (13) are disconnected from the trolley (10). Apparatus as claimed in any one of claims 4 to 6, in which the camera (15) comprises a television or video camera (15) mounted on the trolley or sledge (10) with the lens of the camera (15) facing forwardly. Apparatus as claimed in any one of claims 4 to 7, in which the trolley or sledge (10) is provided with a bar or bars (35) for protecting the camera (15).

Inventors: FRASER, ANDREW ALAN
Applicants: FRASER, ANDREW ALAN
Application year: 1988
Main classification: E03F7
IPC codes: G01M3, E03F7, B08B9