GB2215803A

GB2215803A - Cleaning lance

Info

Publication number: GB2215803A
Application number: GB8902624A
Authority: GB
Inventors: Anthony Christopher Bennett; Peter Taylor; Robert Eddolls
Original assignee: PROGRESSIVE TECHNICAL SERVICES
Current assignee: PROGRESSIVE TECHNICAL SERVICES
Priority date: 1988-02-08
Filing date: 1989-02-07
Publication date: 1989-09-27
Also published as: GB8802778D0; GB8902624D0

Abstract

A mobile high pressure lance 1 for cleaning tubes of boilers, heat exchangers and the like is carried on a rotary shaft (11, Fig 2 not shown) and supplied with water at high pressure. The jetting head of the lance ejects the water through axial and radial outlets to clean the tube. The assembly is carried on a scissor action table 30 which enables the lance 1 to be correctly located opposite a tube to be cleaned. <IMAGE>

Description

IMPROVEMENTS IN THE CLEANING OF THE INTERIOR OF ELONGATE PASSAGES DESCRIPTION The present invention relates to the cleaning of the interior of tubes in heat exchangers, boilers or the like.

In accordance with the present invention a cleaning device for the elongate interior passages of heat exchanger, boiler or the like tubes comprises an elongate tubular lance to enter a tube to be cleaned, a jetting head on the lance to direct effective cleaning jets onto the tube bore and walls, means for supplying cleaning liquid under pressure to the interior of the lance, means for moving the lance longitudinally into an out of the tube to be cleaned and means for rotating the lance and hence the jetting head about the long axis of the lance.

In an embodiment the cleaning device comprises a body mounted for longitudinal sliding motion in a guide track, inlet means for ingress of high pressure liquid to the interior of the body, a rotatable hollow support shaft from which the lance extends coaxially and which is rotatably mounted within said body, the interior of the shaft communicating with the interior of the body so that high pessure liquid can flow from the body and into the lance and the shaft and lance being arranged to be axially rotated-together by said rotation means. The guide arrangements are important in that they not only ensure longitudinal insertion and retraction of the lance but also restrain whip of the lance in use.

The invention will now be described with reference to the accompanying drawings wherein Figure 1 is a side view of apparatus in accordance with the invention; and Figure 2 is a sectional view, on an enlarged scale, of part of the apparatus of Figure 1.

Referring initially to Figure 1 of the drawings a mobile adjustable trolley support carries a lance 1 and its supply and drive systems. The lance 1 protrudes from the front end part of a body 2 longitudinally slidable within an elongate box-shaped trackway 3. The body 2 is of generally H-profile with a base portion 4 to fit the interior of the trackway 3, an upstanding portion 5 to protrude through a slot 6 along the upper part of the trackway and upper laterally outwardly extending flanges 7 extend over the trackway. The body is thus supported and guided during longitudinal movement, lateral movement being restrained. Front and rear pairs 8 of sprockets, the rear pair being driven by motor 9, drive a loop 10 of chain on each side of the trackway 3. Each flange 7 is inserted into a loop 10.Rotation of the drive sprocket 8 can selectively drive the body 2 carrying the lance frontwardly and rearwardly for insertion into and withdrawal from a tube to be cleaned.

Reference will now be made particularly to Figure 2 of the drawings which is a section through the body 2.

The hollow lance protrudes from the front of a shaft 11 rotatable about the long axis and supported at the rear by a coupling 12 fixed to a drive motor 13 at the rear of the body 2 (see Figure 1). The drive motor is driven to rotate the shaft 11 and hence the lance through hoses 14 dispensed from respective retracting reels 15 at the rear of the apparatus as a whole.

The interior bore of the shaft 11 is connected by radial holes 16 (one shown) to an annular space 17 surrounding it. This annular space 17 is sealed at the end by end seals 18 held apart by a spring 19. In operational use high pressure water seats the seal. Vertical passages 20 extend upwardly from the annular space 17 to a feed bore 21 extending longitudinally through the upper part of the block, which bore is connected to entry ports 22 for high pressure water. One of the two ports 22 is connected to a high pressure hose 23 (see Figure 1) and the other port is blocked by a bung.

Referring again to Figure 7, the mobile trolley support is in the form of a hydraulically operated scissor lift table 30. The unit consists of a wheeled base frame 31 carrying pivoted scissor lifting arms 32 which support a table support 33, and are adjustable for height by lifting rams 34.

The table 33 has horizontal guide tracks 35 carrying movable cradles 36 into which the lance assembly is nested. A pair of chain drives 36 driven by end sprockets 37 and hydraulic motors 38 (only one shown) allow for horizontal movement of the cradles and hence the lance unit itself in a horizontal direction transverse to the longitudinal axis of the lance.

This enables the lance position to be located opposite a tube to be cleaned. Fine adjustment is then provided via further hydraulic rams 39 (only one of which is shown). A particular advantage of the scissor action table arrangement is that it is able to accommodate two or more lances alongside one another for multiple cleaning operations.

In use high pressure water, at up to a 1000 bar, entering the selected one of the ports 22 travels through passage 20, annular space 17 and holes 16 into the rotating shaft 11 and to the interior of the lance 1. The lance 1 is rotated and moved forwardly or rearwardly through the tube to be cleaned, cleaning liquid being effectively discharged into the tube by the rotating jetting head. The jetting head has at its end an axial jet outlet to clear the tube bore and radial jet outlets, for example three or four holes, in its walls for cleaning the tube walls.

Arrangements with a non-rotating head have not been effective in cleaning heavily blocked tubes.

Claims

CLAINS

1. A cleaning device for cleaning the elongate interior passages of heat exchanger, boiler or similar tubes comprising an elongate tubular lance to enter a tube to be cleaned, a jetting head on the lance to direct effective cleaning jets on to the tube base and walls, means for supply cleaning liquid under pressure to the interior of the lance, means for moving the lance longitudinally into and out of the tube to be cleaned, and means for rotating the lance and hence the jetting head about the long axis of the lance.

2. A cleaning device according to claim 1 comprising a body mounted for longitudinal sliding motion in a guide track, inlet means for ingress of high pressure liquid to the interior of the body, a rotatable hollow support shaft from which the lance extends coaxially and which is rotatably mounted within said body, the interior of the shaft communicating with the interior of the body so that high pressure liquid can flow from the body and into the lance, and the shaft and lance being arranged to be axially rotated together by said rotation means.

3. A device according to claim 1 or claim 2 in which said jetting head has an axial jet outlet at its end to clear a tube bore and radial jet outlets in its walls for cleaning the tube walls.

4. A device according to any one of the preceding claims comprising a scissor action table assembly for locating the lance in position for cleaning a tube.

5. A device substantially as herein described with reference to the accompanying diagrammatic drawings.