GB2300842A - Powered vehicle with helical ground-engaging members - Google Patents

Abstract

A vehicle is carried on at least one powered helical member that rolls in peripheral contact with the ground, so that rotation of the helical member about its axis propels the vehicle in a general direction of its axis. One such vehicle is a machine for desludging crude oil tanks. The machine is carried and propelled by two helical screws (20, 21), which also entrain deposits and drive them to a collecting mouth (32) of a sludge collector unit (30), whence the deposits are removed from the tank. Each screw (20, 21) may have its own drive unit (26). The invention provides an alternative to tracked vehicles.

Description

POWERED VEHICLES This invention relates to powered vehicles, especially those which are adapted to move relatively slowly. The term "vehicle" is to be understood to mean a mobile apparatus capable of moving along the ground. "The ground" here means any solid surface, which may include, for instance, a floor of a building or other structure (e.g. the floor of an oil storage tank), waste treatment plants, subterranean surfaces such as the floors of sewers, or underwater surfaces such as the beds of lakes or the lagoons of waste treatment plants. A vehicle in the sense of the present Application may or may not be adapted to carry a driver or operator, and is typically a machine for performing some specific operation.

The invention is more particularly, and without limitation, directed to vehicles of those types which, using current technology, would normally be tracked vehicles. There are many working situations in which tracked vehicles are currently used as machines for performing specific tasks, but where much working time is lost due to the need for relatively frequent replacement of the treads of the tracks. One example of a field in which this is true is that of industrial cleaning in the petroleum storage industry, for instance in the removal of sludge from crude oil storage tanks.

One object of the present invention is to provide an alternative to the use of tracks for the propulsion of a vehicle.

In the cleaning of large oil storage tanks, touched on above, it is known to introduce into the tank a small tracked vehicle which is in effect a small bulldozer.

This is used for moving the sludge within the tank, for removal by separate means. Another object of this invention is to provide an improved machine for cleaning such tanks, in which the functions of collection and removal can be combined.

According to the invention, a vehicle (as defined above) has at least one powered helical member arranged to roll in peripheral contact with the ground, whereby rotation of the helical member about its axis propels the vehicle in the general direction of the said axis.

The vehicle may typically have at least two said helical members with parallel axes, in which case it preferably includes means for controlling the relative speeds and/or directions of rotation of the helical members, whereby to steer the vehicle.

Each helical member may have its own separate drive means, and the drive means may take any convenient form. The helical member (also referred to in this Application as a "screw") may be driven by a hydraulic motor supplied through a hose from a remote source of hydraulic pressure; or by an electric motor which may be powered by a battery carried on the vehicle, or from the mains through a cable. The vehicle may on the other hand carry its own prime mover, battery powered electric motors, as mentioned above, being one example.

Where permitted by safety regulations, the vehicle may have an internal combustion engine driving the screw or screws through a gearbox.

In a preferred configuration of vehicle according to the invention, it has two said helical members of opposite hands and with parallel axes, arranged to be driven in opposite directions of rotation.

Where the vehicle is intended for use in connection with the removal of matter from a site, the helical member is preferably arranged to entrain the said matter as the vehicle moves forward. Under these circumstances, where there are two screws of opposite hands on parallel axes, the screws are preferably spaced apart laterally so that they tend to entrain the said matter between them, thus accumulating it for subsequent removal.

In this connection, in one type of preferred embodiment of the invention, the machine includes collecting means adjacent to a rear end of the helical member (or more usually the helical members), for receiving the entrained matter when it reaches the latter as the machine advances. This collecting means will typically comprise a collecting mouth at the rear end of the vehicle, with appropriate suction means for drawing the retrieved matter rearwardly through the mouth. Such a machine is of especial value for the desludging of crude oil storage tanks, since the sludge can then be pumped out of the machine itself and away from the tank, so that collection and disposal are carried out in a single operation, instead of being done in two operations as described above. One advantage of this is that much time can thereby be saved.Another advantage is that the operation is inherently cleaner, and involves operating personnel in less exposure to the hostile environment within the tank.

Vehicles according to the invention may consist of machines for clearing mixed solid matter from confined spaces, in which the conditions may be extremely hostile, as for example in a sewer. The deposits in a sewer tend to consist of many different kinds of solid matter, including rubble, sand, and so on, and can be highly resistant to penetration. To this end, a vehicle according to the invention adapted for working under such conditions preferably has a penetrating nose arranged in advance of the helical member or members, for rotation about an axis whereby to penetrate and/or to break up matter into which the vehicle is advancing.

It will be realised that vehicles according to the invention may take a very wide variety of forms, and may be adapted for many different purposes. By way of non-limiting example only, two specific embodiments of the invention will now be described with reference to the accompanying drawings, which are highly diagrammatic and much simplified, and in which: Figure 1 is an inverted plan view of a machine for desludging crude oil storage tanks in accordance with the invention; Figure 2 is a side view of the same machine; and Figure 3 is a plan view, partly cut away, of a machine according to the invention for preparing solid deposits in a sewer for subsequent removal.

With reference first to Figures 1 and 2, the desludging machine has a robust, rigid body 10, which includes a front cross beam 12 and a rear cross beam 14. The beam 12 carries two front bearings 16, and the beam 14 carries two rear bearings 18, each aligned longitudinally with one of the front bearings so as to define two common longitudinal axes XX and YY.

Instead of being supported on wheels or tracks, the machine has two powered helical members or screws 20, 21, carried by the bearings 16, 18 on the axes XX and YY respectively. Each of these screws rests on the ground (indicated at 24), so as to roll with its helical peripheral surface 22 in contact with the ground.

In this example, each screw 20 or 21 is driven by its own hydraulic motor 26. Also in this example, the two screws are of opposite hands, and they are arranged to be driven in opposite directions of rotation. Thus, when the motors 26 are operating at the same speed, the machine is driven along the ground in a straight line.

Its forward direction of motion is indicated by an arrow in Figure 1.

It will be realised that in this case the machine can easily be steered by varying the relative speeds of the two motors, or even when necessary, by reversing one of the motors so as to vary the relative directions of rotation. Accordingly, the machine is highly manoeuvrable, an advantage in a confined space such as an oil storage tank. Suitable control means for achieving this steering by differential speeds is well known from the technology of tracked vehicles, and need not be described here.

The rear cross beam 14 carries a support structure 28 which is omitted from Figure 1 for clarity. The support structure 28 carries a sludge collection unit 30, which may be of any suitable design. It has a collecting mouth 32 which is arranged behind the space 34 lying between the two screws 20 and 21. Suitable screens, indicated diagrammatically at 36, are provided for guiding sludge into the mouth 32. These screens may also be adapted for scraping sludge from the rear ends of the screws; or separate scrapers for this purpose may be provided. The unit 30 includes a sludge pump (not shown), powered by a hydraulic motor 31, for drawing sludge rearwardly through the mouth 32.

In operation, the motors 26 are operated so that the machine is driven forward by rotation of the two screws 20 and 21. As they advance through the deposits in the tank, the screws entrain the deposits in their helices and accumulate them in the intervening space 34, so that the mouth 32 receives this entrained matter as it reaches it with the forward motion of the machine, whereupon it is removed by the pump in the sludge collection unit 30, through an outlet 36 of the latter.

The outlet 36 may be connected to a pulveriser (not shown) for comminuting any solid matter in the retrieved sludge, or directly to a pipe extending out of the oil tank for subsequent disposal of the sludge.

If a pulveriser is fitted, such a pipe is of course connected to the discharge side of the pulveriser.

A gun 40 may be carried by the machine for injecting hot or cold cutting fluid into the deposits in the oil tank, so as to assist in the breaking up of any solid matter. In place of the gun, or in addition, a highpressure water jetting head may be provided.

It should be noted that in all the drawings, the helical screws are, like other components, indicated only diagrammatically. In Figures 1 and 2, however, each screw is in the form of two helical webs mounted on a substantial cylindrical shaft 42, giving in this case a two-start helix. The screws may be of any suitable material or materials, but where the vehicle is to be used in environments where exposed metal surfaces are not permitted, at least the exposed surfaces of the screws are preferably of a material such as nitryl rubber or neoprene.

A machine such as that shown in Figures 1 and 2 is also suitable for use in environments other than crude oil storage tanks, for example in lagoons, lakes and so on.

In that case, the screws 20, 21 may be of metal.

Beyond the foregoing remarks, the geometry and general design of the helical screws carrying machines according to the invention need not be discussed here, since it can be of any suitable form. The design and manufacture of heavy-duty helical screws is well known in other contexts, such as that of screw conveyors.

Reference is now made to Figure 3, which shows a machine for penetrating the solid deposits in a sewer, so as to prepare them for subsequent collection by other means. It will of course be realised that, as with the machine described above, this sewer scavenging machine may be provided with means for collecting the matter penetrated by the machine and for passing it away for disposal.

In Figure 3, the machine again has two helical screws, 50, 51, which in this example are again of opposite hands, each being driven by its own hydraulic motor 54.

Each screw has a shaft 56 which is carried by a heavyduty rotation and thrust bearing assembly 58 (one of which is shown diagrammatically in cross section), the shaft being coupled through a suitable coupling 60 to its motor 54.

The bearing assemblies 58 are part of a body structure 62 of the machine. The body structure can of course take any suitable form, and may include a stiffening structure (not shown) in front of the screws 50 and 51.

Figure 3 shows the body structure only diagrammatically, but in dismountable form consisting of two halves, which are fastened together by means of bolts passing through two slots 64 in one of the halves and selected holes 66 in the other half. In this way, examples of two desirable features are illustrated, namely the capability of the machine for being partly dismantled for transport to and from the working site, and a variable-width facility for working in sewers of different sizes, and to permit entry through manwaytype access holes into sewers, tanks and the like.

A penetrating nose 70 is carried on the front end of each shaft 56. Each nose 70 may have any suitable configuration, for example that of a corkscrew, for penetrating and loosening the solid deposits in the sewer. Preferably it is such as to break up the solid matter, so that the latter can be more easily traversed by the screws 50 and 51. The helix of each screw may have a sharp edge so as to assist the breaking up of the solid deposits.

The machines shown in the drawings may if desired by remotely controlled, in any known way.

It will be realised that the number of helical members carrying a vehicle according to the invention is not necessarily two. There may be more than two, or in some applications there may be only one. In the latter case, the machine may be provided with idle wheels or skids to maintain stability.

Claims (13)

1. A vehicle having at least one powered helical member arranged to roll in peripheral contact with the ground, whereby rotation of the helical member about its axis propels the vehicle in the general direction of the said axis.

2. A vehicle according to Claim 1 having at least two said helical members with parallel axes.

3. A vehicle according to Claim 2, including means for controlling the relative speeds and/or directions of rotation of the helical members, whereby to steer the vehicle.

4. A vehicle according to any one of the preceding Claims having a separate drive means for each helical member.

5. A vehicle according to any one of the preceding Claims having two said helical members of opposite hands and with parallel axes, arranged to be driven in opposite directions of rotation.

6. A vehicle according to any one of the preceding Claims, being a machine for use in connection with the removal of matter from a site, wherein the or each helical member is arranged to entrain the said matter as the vehicle moves forward.

7. A vehicle according to Claim 6 when dependent on Claim 5, wherein the helical members are spaced apart laterally so as to entrain said matter between them.

8. A vehicle according to Claim 6 or Claim 7, having collecting means adjacent to a rear end of the helical member or members, for receiving the entrained matter when it reaches the latter as the vehicle advances.

9. A vehicle according to Claim 6 when dependent on Claim 5, wherein the helical members are spaced apart laterally so as to entrain the said matter, the machine having a collecting mouth at its rear end for receiving the entrained matter when it reaches the latter as the machine advances, and suction means for drawing the matter rearwardly through the mouth.

10. A machine according to Claim 9, further including a pulveriser downstream of the collecting mouth.

11. A vehicle according to any one of the preceding Claims, having a penetrating nose arranged in advance of the helical member or members, for rotation about an axis whereby to penetrate and/or to break up matter into which the vehicle is advancing.

12. A machine for removing sludge or other matter from oil tanks, lagoons and the like, substantially as described in the foregoing description with reference to Figures 1 and 2 of the accompanying drawings.

13. A machine for preparing deposits for removal from a sewer, substantially as described in the foregoing description with reference to Figure 3 of the accompanying drawings.