Classifications

• • E—FIXED CONSTRUCTIONS
  • E03—WATER SUPPLY; SEWERAGE
  • E03F—SEWERS; CESSPOOLS
  • E03F9/00—Arrangements or fixed installations methods or devices for cleaning or clearing sewer pipes, e.g. by flushing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto 
  • B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
  • B08B9/027—Cleaning the internal surfaces; Removal of blockages
  • B08B9/04—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes
  • B08B9/049—Cleaning the internal surfaces; Removal of blockages using cleaning devices introduced into and moved along the pipes having self-contained propelling means for moving the cleaning devices along the pipes, i.e. self-propelled
  • B08B9/0495—Nozzles propelled by fluid jets

Definitions

• the present invention relates to a head for use in 5 cleaning sewers, of the type known as a "jetting head”.
• jetting head is one of a number of techniques which have been adopted for cleaning sewers to
• a hose is fed down the sewer and water is jetted at high velocity from a nozzle on the end of the pipe. Initially, the jetting of the water serves to propel the head along the sewer a certain distance. Subsequently, the head is winched back,
• jetting heads offer advantages over some other methods of sewer cleaning, it is still a relatively expensive procedure both in terms of the capital cost of the jetting equipment and also in terms of the
• a jetting head for use in cleaning a sewer comprising a body including an inlet for connection to a pipe carrying water, and an outlet for a jet of water, characterised in that the body is arranged to lie generally horizontally in
• the invert of the sewer includes an outlet arranged to direct a jet of water downwards at a shallow angle to the longitudinal axis of the body, in use the jet striking detritus in the invert at a shallow angle of attack.
• the outlet directs the jet at an angle of less than 25° to the longitudinal axis of the head, and more preferably less than 10°.
• the jet is directed at an angle of substantially 5°.
• the present inventor has recognised that a very marked improvement in the performance of the jetting head can be realised by directing the jet at a far shallower angle so that it is almost parallel to the longitudinal axis of the sewer.
• the jet is then effective to sweep downstream the detritus from the point at which the jet impacts. Any detrital material overlying the point of impact then in turn falls downwards, is struck by the jet and is also swept downstream. Functioning in this manner, the head can clear a sewer at a far greater rate than has hitherto been possible.
• such a head using a water pressure of between 1500 and 2000 psi was able to clear a 30 metre length of 15", half full sewer in 25 minutes.
• a conventional head used on the same sewer was found to take twice as long, that is 50 minutes, to clear a 30 metre length, and still left depositions in the invert.
• the head includes a hollow body, an inlet on one end wall of the body, an outlet formed in a bottom wall of the body, and a channel extending downwardly from the outlet at a shallow angle, the far end of the channel being open to direct the jet of water at the invert.
• a method of cleaning a sewer includes the step of directing a jet from a jetting head at a layer of detritus in the invert of the sewer at a shallow angle from a position such that the jet impacts upon the detritus in a region below the top of the layer.
• Figures 2A and 2B are a sectional view and a side elevation of one example of a jetting head in accordance with the present invention in use;
• Figure 2C is a simplified sectional view showing the water flow within the head;
• Figure 3 is a sectional view on line D-D of the jetting head
• Figure 4 is a plan view on line B-B of the jetting head.
• Figure 5 is a plan view on line C-C of Figure 4.
• FIGs 1A and IB show the manner of use of a jetting head, with reference to a prior art head.
• the head 1' is attached to the end of a flexible hose 2" connected to a pump arranged to supply water under pressure.
• the hose and jetting head are inserted into the sewer through a manhole cover. Water is sprayed generally backwardly from the head in the directions indicated by the arrows in Figures 1A and IB. This serves to drive the head down along the sewer, although the distance of travel in the case of this prior art head is relatively limited.
• the head is then drawn back by the hose winding in along the sewer, cleaning the sewer as it moves.
• a jet from the head impacts upon the detritus collected in the invert 5' of the sewer, loosening the detritus so that it is carried along by the downstream flow of water in the sewer. Typically the loosened detrital matter is then collected by a suction unit.
• FIG. 1A shows one example of a head formed in accordance with the present invention in use.
• This head is intended for use in sewers with a diameter of 9" (225 mm) to 4 ' (1.2 m) and has a 25 mm (1") direct connection. 1%" (31 mm) or 1 " (37 mm) connections are used on heads for sewers up to 7'6" (2.25 m).
• the head is fitted to the end of a pipe connected to a high pressure water source.
• a single fan- shaped jet is output from the head from an outlet 0 in the base a hollow body 6 of rectangular cross-section. Water from the outlet O is guided through a channel 7 which directs the jet away from the head at a shallow angle ⁇ of 5° (for clarity the angle is exaggerated in Figure 2) .
• a greater angle ⁇ up to typically 9°, may be used according to the condition of the sewer, or depending on the water pressure and the angle needed to give the required propulsion of the head.
• the jet strikes the detritus 8 with a large component of velocity in the longitudinal direction. Most of that velocity is effectively absorbed by the detrital matter and serves to speed its movement downstream, by contrast with the prior art in which the velocity was largely spent on impact with the wall of the invert as a single jet generally away from the greatest depth and heaviest concretion.
• a further important property of the position and angle of the jet is that it strikes the base of the layer of detritus first, rather than impacting from the top.
• Removing the bottom of the layer of detritus has the effect of weakening and loosening the overlying layers which then in turn fall down and are quickly swept away. This further serves to increase the speed with which the detritus can be cleared.
• a further feature of this example of the present invention is use of a closed circuit television camera CCTV mounted on the upper surface of the body of the head. Hitherto, after a sewer has been cleaned, it has been inspected in a separate operation, necessitating the use of additional equipment. A further significant saving in time and capital cost is achieved by combining an inspection camera with the jetting head itself, so that the progress of the cleaning can be monitored at the same time it is carried out. (When CCTV is used, the head is winched back by the hose.)
• a coupling 8 is formed in the head which, in use, connects a 1" (25 mm) pipe from the jetting machine to the jetting head.
• the coupling is formed in the end face 9 of a hollow body of rectangular cross-section of welded construction with walls formed from mild steel 15 mm thick.
• the body is mounted on skis 10 having a spacing of 117.5 mm. In use the skis ride along the bottom of the invert.
• an outlet 0 is formed in the bottom wall 11 of the body. As seen in the plan C-C, this outlet is rectangular.
• a channel 12 extends downwardly from the outlet at an angle of 5° to the longitudinal axis of the head.
• the bottom portion 12B of the channel is open and in use it is from here that the jet of water exits the head.
• the channel 12 has diverging walls so that the jet exits as a fan-shaped generally flat sheet of water, shown by cross-hatching in Figure 5. Although in the figures individual skis are shown, these may be replaced by a sheet extending from one side of the head to the other having the same general longitudinal profile as the skis.
• Figure 2C shows the dynamics of the water flow within the body from the coupling to the hose, as presently understood.
• Water flows into the head at high velocity from the coupling C and flows across the head until it encounters a turbulent boundary region associated with the opposing end wall 14 of the head. The flow of water is turned back at this point and exits through the outlet 0.
• An upstanding block 13 of rectangular plan is fixed to the bottom wall of the head immediately adjacent the outlet O, as seen in Figure 4. This serves to increase the velocity of the flow into the outlet o while at the same time protecting the outlet from the direct impact of the incoming water from the inlet C.
• the height of the block 13 is less than the height of the inlet so that the initial inwards flow passes over the block.
• the front of the head is in the form of a tapered "prow". This facilitates forwards movement of the head through the sewer.
• the inner wall of the body is radiussed in the horizontal plane but square to the top and bottom walls of the body.
• the presently described example is intended to operate at water flow rates typically around 45 gallons/minute and has a weight of around 28 lbs (13 kg) .
• This weight gives the necessary stability for the head as it moves through the detritus in the sewer.
• it is desirable to increase the weight of the head for example for a flow rate of 55 gallons/minute the weight of the head is desirably around 32 lbs (14.5 kg).
• it is preferable to include in the head means to step down the pressure, rather than further increasing the weight of the head.
• the outlet velocity is maximised by moving the outlet and block away from the opposing end wall and towards the inlet.
• the minimum distance between the outlet and the inlet however is constrained by the need or the outlet channel 12 to be of sufficient length to give the required shape of jet, and by the need for a sufficient spacing (W4) between the end of the channel and the end of the head.
• W4 a sufficient spacing between the end of the channel and the end of the head.
• the head is mounted on skis 10. As well as facilitating the movement of the head through the detritus in the invert of the sewer, these also serve to lift the head and the outlet so as to ensure that the region where the jet impacts upon the detritus is not immediately under the head but is spaced some distance in front. With skis of height 12.5 mm, the point of impact of the jet upon the detritus is typically 10-15 cm away from the head, depending on the sewer diameter.
• the example of the head described, with a 1" (25 mm) inlet, is suitable for 9" (225 mm) to 4 ' (1.2 m) sewers and in use would operate with a water delivery rate of 40-50 gallons/minute.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Public Health (AREA)
• Water Supply & Treatment (AREA)
• Health & Medical Sciences (AREA)
• Sewage (AREA)
• Percussion Or Vibration Massage (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Particle Formation And Scattering Control In Inkjet Printers (AREA)
• Seal Device For Vehicle (AREA)
• Fuel-Injection Apparatus (AREA)
• Jet Pumps And Other Pumps (AREA)
• Cleaning In General (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10713103

Family Applications (1)

Country Status (7)

Cited By (2)

Citations (4)

• 1992
  • 1992-03-30 GB GB929206910A patent/GB9206910D0/en active Pending
• 1993
  • 1993-03-22 AT AT93906714T patent/ATE162575T1/de active
  • 1993-03-22 AU AU37618/93A patent/AU3761893A/en not_active Abandoned
  • 1993-03-22 ES ES93906714T patent/ES2114043T3/es not_active Expired - Lifetime
  • 1993-03-22 WO PCT/GB1993/000576 patent/WO1993020295A1/en active IP Right Grant
  • 1993-03-22 DE DE69316605T patent/DE69316605T2/de not_active Expired - Fee Related
  • 1993-03-22 EP EP93906714A patent/EP0633969B1/en not_active Expired - Lifetime

Patent Citations (4)

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