US3895756A

US3895756A - Method and apparatus for cleaning vessels

Info

Publication number: US3895756A
Application number: US453600A
Authority: US
Inventors: Ben E Jaeger
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-22
Filing date: 1974-03-22
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22

Abstract

Apparatus is disclosed wherein a high pressure spray nozzle is inserted into an enclosure or vessel for the purpose of automatically cleaning the interior thereof. The spray nozzle is connected to first and second successive swivel joints mounted in perpendicular to one another such that the nozzle may be rotated about two axes. An automatic external control mechanism is connected to respective rotary actuators which rotate the nozzle around the respective axes. The control mechanism varies and controls the speed and degree of movement of the spray nozzle in both axes and also automatically reverses the rotation of the nozzle in both axes. The control may be set to automatically operate the nozzle in various patterns of coverage and shape.

Description

United States Patent Jaeger July 22, 1975 [5 METHOD AND APPARATUS FOR 3.764.075 10/1973 Gagliardo 239/587 x R27,612 4/1973 Ruppel et al. 239/227 CLEANING VESSELS [76] Inventor: Ben E. .laeger, Rt. 2, Box 49, Plano,

[22] Filed: Mar. 22, 1974 [21] Appl. No.: 453,600

[52] U.S.Cl 239/227; 118/317; 134/167 R; 134/181; 239/264 [51] Int. Cl. B05B 3/00; 1305B 13/06 [58] Field of Search 239/225, 227, 243, 245, 239/264, 265, 587; 134/167 R, 172, 180, 181, 22 R, 24; 118/254, 305, 306, 317

[56] References Cited UNITED STATES PATENTS 1,880,272 10/1932 Panther, Jr. 239/587 X 2,045,752 6/ 1936 Butterworth 134/24 X 2,082,330 6/1937 Frede et a1 239/227 2,109,075 2/1938 Ruth 239/227 2,116,935 5/1938 Richard et a1. 239/227 3,319,889 5/1967 Nelson 239/227 X 3,595,256 7/1971 Waltman et a1. 239/227 X 3,601,136 8/1971 Marcham 239/227 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Andres Kashnikow Attorney, Agent, or Firm-Gary, Juettner, Pyle & Cullinan [57] ABSTRACT Apparatus is disclosed wherein a high pressure spray nozzle is inserted into an enclosure or vessel for the purpose of automatically cleaning the interior thereof. The spray nozzle is connected to first and second successive swivel joints mounted in perpendicular to one another such that the nozzle may be rotated about two axes. An automatic external control mechanism is connected to respective rotary actuators which rotate the nozzle around the respective axes. The control mechanism varies and controls the speed and degree of movement of the spray nozzle in both axes and also automatically reverses the rotation of the nozzle in both axes. The control may be set to automatically operate the nozzle in various patterns of coverage and shape.

12 Claims, 9 Drawing Figures PATENTEDJuL 22 ms 13, 8 95; 7 56 SHEET 1 CON T 'QOL BOX METHOD AND APPARATUS FOR CLEANING VESSELS BACKGROUND OF THE INVENTION The cleaning of enclosed tanks and other confined or inaccessible areas often proves to be a difficult, tedious and time consuming task and must often be accomplished by manual labor. Such cleaning operations may also involve exposure to toxic or corrosive substances and vapors and otherwise create a hazardous environment for the worker.

A typical situation is the cleaning or removal of sludge from the bottom of automotive or railway tank cars, which have only a small access opening at the top. Current practice requires an individual to be lowered into the tank to loosen and scrape the sludge.

Various spray devices, such as shown in US. Pat. No. 3,401,060 and No. 3,736,948 have been proposed to allow use of a movable spray nozzle to clean the interior surface of a container.

SUMMARY OF THE INVENTION The present invention provides a high pressure spray nozzle or jet mounted for universal movement about two perpendicular axes. Separate hydraulic actuators are provided to rotate the nozzle in either direction about both axes. The hydraulic actuators are connected to and activated from a remote control device, which is air operated and contains means for adjusting the speed and degree of sweep of the jet about the two axes. The device enables the jet to be directed along a defined pattern of substantially any shape.

The spray assembly comprised of the nozzle and its associated actuators are small enough to be lowerd into the top opening of the tank, and the assembly is connected by liquid pressure lines to the control device and to a source of pressurized cleaning liquid.

In the use of the cleaning device, it is possible to preset the control in accordance with the dimensions of the vessel and to program the sequence of nozzle movement to achieve the most efficient sequence and pattern of nozzle movements.

THE DRAWINGS FIG. 1 is an outline elevational view of a railway tank car together with the cleaning apparatus of the present invention;

FIG. 2 is an outline end view of the tank car and apparatus of FIG. 1;

FIG. 3 is an elevational view of the spray portion of the apparatus of the present invention;

FIG. 4 is an end view of the apparatus shown in FIG.

FIG. 4a is a schematic view illustrating the two axes of rotation of the apparatus shown in FIGS. 3 and 4;

FIG. 5 is a top view of the apparatus shown in FIGS. 3 and 4;

FIG. 6 is a schematic view of the control portion of the apparatus of the present invention;

FIG. 7 is an elevational view, with portions broken away of the control box which houses the control of FIG. 6; and

FIG. 8 is a top view, with portions broken away of the apparatus shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 1-5, the apparatus of the present invention is generally comprised of two major components, namely, a control box 10 and a spray assembly 12. As shown in FIGS. 1 and 2, the spray assembly 12 is adapted to be lowered into the hatch 14 or other relatively narrow top opening of a tank 16 or other enclosed vessel. The illustrative tank 16 is part of a railway tank car supported upon a trunk comprising well known components, including side frame and bolster means (not shown) supported upon axle and wheel assemblies 18 adapted to travel on rails. The control box 10 serves to control the movement of the spray head assembly 12 and is located at any convenient remote position. In its usual form, the tank 16 also has a bottom drain opening 17 to facilitate emptying and cleaning of the tank.

As shown in FIGS. 3, 4 and 5, the spray assembly comprises a horizontal support cover 20 having a vertical support rod 22 secured to and passing centrally therethrough, the upper end of said rod terminating in a lifting loop 24 for engagement by the hook of a lifting means, such as a hoist (not shown). The cover 20 is sufficiently large in diameter to rest on the hatch 14 of the tank 16 and thereby supports the spray assembly during the cleaning operation. The lower end of the vertical support rod 22 is secured to and supports the working portion of the spray assembly, as will be hereinafter described.

The cover 20 is preferably provided with doors 26 mounted on hinges 28 (FIG. 5) to enable visual inspection of the tank interior during and after the cleaning operation. The cover has handles 30 to facilitate guiding of the assembly to the proper location, and the hinged doors 26 are also preferably equipped with suitable handles 32.

The spray apparatus utilizes a single stream, high pressure spray head 34 mounted on a movable outlet pipe 36 and having a suitable nozzle 38, which produces a concentrated or substantially non-diverging spray pattern or high pressure jet. The spray head is fed by a large diameter inlet pipe 40 which passes through the cover 20 and is connected to a high pressure source 42 of cleaning liquid (FIG. 1).

As best shown in FIGS. 3 and 4, the spray apparatus includes means to rotate or swing the outlet pipe 36 and spray head 34 about a first horizontal axis A-A' and a second horizontal axis B-B' perpendicular to the first. This is accomplished by leading the inlet pipe 40 through a first liquid tight swivel joint 44 located on the first axis A-A' and then downward through a second liquid tight swivel joint 46 located on the second axis 8-8, which is connected to the outlet pipe 36. This arrangement is shown in simplified schematic form in FIG. 4a wherein it may be seen that the output of motion from the first swivel joint 44 is the input reference for the second swivel joint 46, which enables the axis of the outlet pipe 36 to be moved about either or both of the joints.

More specifically the stationary depending inlet pipe 40 is connected to a fixed right angle joint 48, which leads into the first slip joint 44 located along the transverse horizontal axis A-A. The pipe leading from the other side of the slip joint is rotatable in both directions about axis AA (see arrow 50 in FIG. 4a), and is connected by a suitable series of successive

right angle bends

52, 54 and 56, to the inlet of the second slip joint 46. The bend 52 is located, in terms of previous references, in a transverse horizontal plane, whereas the

bends

54 and 56 are located in a longitudinal vertical plane. The outlet of the second slip joint 46 is connected to a rotatably mounted right angle bend 58, which is connected to the outlet pipe 36. The outlet of slip joint 46 is thus also rotatable about the axis BB; as indicated by arrow 59 in FIG. 4a.

Two-way rotary

hydraulic actuators

60 and 62 are operatively connected on the outlet parts of the respective slip joints 44 and 46; and serve to rotate said parts in both directions about the respective axes A-A' and B-B. The

actuators

60 and 62 are substantially identical and conventional in construction, each comprising a double acting hydraulic cylinder 64 containing a linear moving piston mounted on a rod or rack, which actuates a pinion of an axially rotatably shaft, such as that shown at 66 in FIG. 3. One end of the rotatable shaft 66 is provided with a fitting 68 which embraces the respective outlet parts of the joints 44 and 46 along the respective axes A-A' and B-B', thereby serving to move the outlet pipe in both directions about each axis, as indicated by the dotted arrows at 70 and 72 in FIGS. 3 and 4. Flow of hydraulic fluid into one end of the cylinder 64 causes rotation of the shaft 66 and its associated parts in one direction, and flow into the other end causes rotation of the shaft in the other direction.

The actuator 60 connected to the outlet of the first slip joint 44 is secured to a mounting plate 74 affixed to the lower end of the downwardly depending support rod 22. The other actuator 62 is mounted on a plate 76 having a portion which is secured to the fitting 68 on the other actuator, whereby actuator 62 moves with said fitting about axis A-A.

The

actuators

60 and 62 are each responsive to rates and volumes of flow of hydraulic fluid from respective pairs of

hydraulic supply lines

78 and 80 connected at opposite ends of the respective cylinders 64. The supply lines 80 connected to actuator 62 are preferably flexible because said actuator rotates along with the assembly located thereabove. The pairs of

hydraulic lines

78 and 80 lead upward through the cover to respective pairs plug-type fittings 82 and 84 (FIG. 5), which are connected by suitable lines to the control box 10.

The components of the control box 10, together with the connection to actuators 60 and 62, is shown s'che matically in FIG. 6. In contrast with the

actuators

60 and 62, which are hydraulically powered, the control box is air operated from a suitable compressed air supply 90. As shown, each of the actuators is controlled by separate two-branch circuits, and except for certain differences defined hereafter, the two circuits shown on the left and right hand sides of FIG. 6 are identical. With respect to identical corresponding parts, theparts for the circuit which activate the actuator 60 will be designated on the drawing by a numeral and the corresponding identical part in the circuit will be designated with the same numeral and the suffix a.

The air supply 90 leads through the inletof a three way manual master valve 92 having one of its outlets leading through a pressure control valve 94 to a conduit 93 connected to the inlets of various air-operated devices of the control system, namely a reversing valve 96 and a pair of

opposed limit valves

98 and 100. The distance between

limit valves

98 and 100 is manually adjustable, and the valves have respective opposed facing plungers l02,"which when compressed, switch the valve from an exhaust position, as shown, to a position which connects the air conduit 93 through suitable lines to respective opposite sides of the reversing valve 96, thereby serving to operate the reversing valve between alternate positions.

The reversing valve 96 is air-operated by limit valves 98 and and has a pair of alternate outlets which are connected to respective air-

oil reservoir tanks

104 and 106, the respective-hydraulic outlets of whichlead to opposite sides of a double acting drive cylinder 108. The hydraulic outlet of the tank 104 is preferably connected to one sideof the drive cylinder 108 through 2 switching and control circuit comprising a three position manual valve 110, with one setting to an off position, one setting leading through an adjustable needle valve 112, and the other setting bypassing the needle valve and leading directly to the drive cylinder 108.

At one end of the cylinder is axially mounted a slavedriven master cylinder 114, which includes an axially projecting rod 116 having a terminus 118. The drive cylinder 108 is hydraulically isolated from the master cylinder 1 14 but serves to drive the same as well as the rod. The master cylinder 114 is filled with, hydraulic fluid and is hydraulically connectedto and drives the rotary actuator 60. More specifically, the master cylinder 114 has opposite end outlets 120 which are connected to the respective supply lines 78 of the actuator 60. The outlets 120 and master cylinder 114 are provided with a pressurized source of hydraulic fluid through a common line 122 leading to the hydraulic outlet of an air-oil tank 124 that is pressurized from air supply 90 through master valve 92 and a separate pressure control valve 126.

Needle valves 128 leading to the exhaust are provided in each outlet 120 of the master cylinder 114 to bleed the system, and a needle valve 130 is connected between the outlets and may be opened at the end of a stroke to synchronize the actuator 60 with the master cylinder 114. In addition, an adjustable valve 132 may be provided between one of the outlets and the actuator 60 to balance the enclosed system, thereby assuring the'same rate of movement of the actuator in both directions.

It should be understood that the terminus 118 of the rod 116 is positioned in the actual control apparatus so as to reciprocate between the

opposed limit valves

98 and 100 and alternately engage the respective plungers 102 thereof. In turn, the reversing valve is actuated to reciprocate the drive cylinder 108. g

In summary, the control device comprises interrelated air and hydraulic circuits by which the speed and extent of sweep of the actuator. 60'may be controlled. The air supply circuit is reversible to alternatively supply hydraulic fluid on opposite sidesof the drive cylinder 108, causing the cylinder toreciprocate at a controllable rate, which simultaneously actuates the slavepowered actuator 60 and reciprocates the rod 1 16. The

limit valves

98 and 100 are each adjustable toward and away from one another to limit'the extent .of the stroke of the power cylinder 108,,master cylinder 114 and rod 126, before the terminus 11 8 engages one of the plungers 102. ca'u'sin ga reverse toward the opposite direction. This, in turn, limits the degree of movement in the master cylinder l14 a'r'1d degree of rotation of the spray head connected to the actuator 60.

Stated in other terms, the

limit valves

98 and 100, reversing valve 96, power cylinder 108, master cylinder 114 and rod 116 are interconnected and in effect constitute a closed loop of components driven from the air supply 90. The closed loop circuit provides an effective means to control the extent of stroke of the master cylinder 114 on either side of a neutral position, as determined by the settings of the

limit valves

98 and 100. The loop also provides means to automatically reverse the stroke of the

cylinders

108 and 114 and the rod The portion of the control system on the right-hand side of FIG. 6 is employed separately to power and control activator 64 and contains components and connections which are identical to that described in connection with activator 60 with one exception. In addition to the reversing function afforded by the rod 116a, said rod may also carry a cam surface 140 which is engaged by a spring-loaded plunger 142 of a variable valve 144 connected on the line of needle valve 112a between the control switch 110a and the drive cylinder 108a. The rate of hydraulic liquid flow to the drive cylinder 108a is therefore determined by the variable degree to which the valve 114 is closed or opened. Depending on the shape of the cam surface 140, i.e., its distance relative to the maximum open extent of the plunger 142, the amount of hydraulic flow to the cylinder 108a may be varied continuously or intermittently as the rod 116 is reciprocated. This feature is used to delay or speed up certain phases of movement of the actuator 62 as it re tates between the limits prescribed by the

limit valves

98a and 100a.

In the embodiment shown, the cam surface 140 is V- shaped relative to the plunger 142. As a result, the speed of the rod 116a will progressively decrease as it approaches each end of its prescribed distance of travel, and the speed will be at a maximum within the intermediate arc of travel. In visualizing the actuator 62 being connected to a spray head, it will be understood that the head, as it passes through a downwardly facing position. will sweep outward to either side at a progressively decreasing rate of speed.

It will be understood that both sides of the control may be provided with a variable valve to variably control speed, and the shape of the cam may be changed to program any desired speed sequence within the design limits of the system. At the same time, the

needle valves

112 and 112a may be adjusted to control the maximum speed of operation of each actuator.

The components shown in FIG. 6 may be conveniently arranged in the simple enclosure, as shown in FIGS. 7 and 8. In these figures, the air and hydraulic lines have been omitted for the sake of clarity, and only those components shown on the right-hand side of FIG. 6 are shown in and described in detail for the sake of brevity.

The facing

limit valves

98a and 100a are slidably supported upon a pair of spaced

upstanding bars

150 and 152 secured to the base 154 of the enclosure, generally indicated at 156, and a releasably gripping device 158 is provided on each valve to releasably secure each valve in a given or predetermined position on the bars. The forwardly facing surface of the front bar 152 may have graduations marked thereon, as shown in FIG. 7, which illustrate the setting to determine the extent of reciprocal movement of the terminus or crosshead 160 on the rod 116a. The graduations are preferably marked in degrees, corresponding to the degree of rotation of the spray jet on either side of a neutral reference point, indicated at zero on the scale. As shown in FIG. 7, the cam is mounted on the crosshead and is movable therewtih.

It will be understood that the other side of the control device which controls actuator60, as shown in dotted lines in FIG. 8, is identical in arrangement to the portion described above, except that the cam 140 and variable valve 144 are omitted.

The operation of the entire device will now be described particularly in connection with the cleaning of the tank car 16 shown in FIGS. 1 and 2. In the example shown, the car contains a layer of solid sediment in the bottom but is otherwise empty. By knowing the internal dimensions of the tank and the approximate depth of the sediment, it is possible to determine the most advantageous maximum arc of sweep of the spray apparatus in order to cover the perimeter of the sediment. In the case of the tank of FIGS. 1 and 2, the maximum degree of pivot desired in the longitudinal direction is 72 on either side of a vertical axis, said vertical axis being the starting point and axis of reference of the spray pipe 36. As shown in FIG. 2, the maximum degree of transverse pivot required to cover the chordal extent of the sediment bed 180 is 32 on either side of said vertical axis.

As shown in FIGS. 3, 4 and 4a, the longitudinal back and forth pivoting of the spray head 34 is about the axis B-B (actuator 62) and the transverse pivoting is around axis A-A (actuator 60). Since the actuators are mounted successively on one another, it is possible to pivot the spray head around perpendicular axes A-A' and B-B' either simultaneously or separately, depending upon the setting of the FIG. 6 control circuits.

In order to ready the device for operation, the hatch cover of the tank car is removed, drain 17 is opened, and the spray apparatus 12 is lowered into the hatch opening until the cover 20 engages the top of the hatch 14. In such position, the spray apparatus is located in the uppermost central interior portion of the tank 16 with its longitudinal rotation axis BB in parallel with the axis of the cylindrical tank and its transverse axis A-A perpendicular thereto. The

lines

82 and 84 from the spray apparatus are then connected to the connections on the control box 10.

When in position, the spray apparatus 12, in the embodiment shown, operates from substantially a fixed location and directs a liquid jet at a substantially rectangular bed of sediment 180 at the bottom of the tank 16 along a path and at a speed determined by the control box 10. The neutral position of the spray head 38 is when it faces directly downward and is perpendicular to the sediment bed. The extent of transverse and longitudinal sweep is determined by the setting of the distance between the limit switch-

valves

98 and 100 and 98a and 100a, respectively.

In order to set the control, the appropriate angles between the limit valves are set by sliding the

valves

98 and 100 on the bars 152, as shown in FIG. 8 until the desired setting is obtained. In the example shown, the longitudinal setting (at top portion of FIG. 8) is set at 72 on either side of zero, and the transverse is set at 32 at either side of zero.

Referring to FIG. 6, the master switch 92 is set at auto, which causes air to be supplied from source 90 to the air operated components.

Switches

110 and 110a are normally set at auto, which causes hydraulic pressure to be imposed on the hydraulic components. The speed of rotation of

theactuators

60 and 62 may be controlled on the auto setting by manipulation of the needle valves 112-112(4.

When the device is set as described, the power cylinder 108 moves the rod-terminus 118 toward one of the

limit valves

98 or 100 until the plunger thereon is engaged, which causes air to flow into one end of the air valve 96, which moves to a new setting and exhausts air pressure from one of the

tanks

104 or 106, while pressurizing the other tank. This causes a reversal of flow of hydraulic liquid to the ends of the cylinder 108 and causes it to reverse its direction of movement. The hydraulic cylinder 108, master cylinder 114 and rod 116 therefore continue to reciprocate back and forth, whereby hydraulic oil alternately flows into either side of the actuator 64, causing the pivoting back and forth of the jet spray at a rate determined by the rate of hydraulic flow through the needle valve 112. If desired, the bypass setting on valve 110 may be employed, which allows the maximum possible rate of speed.

The function of the longitudinal portion of the control device is identical to the transverse portion, except for the additional function of the variable valve 144. In the case of longitudinal movement in the example shown in FIG. 1, the high pressure jet must travel a progressively greater distance from the spray head as the angle of rotation is increased, which allows the spray to diverge more and lose some of its speed and effectiveness. The valve 114, by reason of its coaction with the cam surface 140, progressively closes the valve as the rod 116a approaches the maximum extent of movement in either direction as determined by the

limit switches

98a and 100a, and the speed of rotation on the actuator 62 decreases accordingly. In this manner, the dwell time of the spray progressively increases toward the end of each reciprocal movement of the rod 116a and provides more spray time near the ends of the tank.

The control of FIG. 6 therefore causes the spray to be moved about a longitudinal and transverse axis at a controlled rate of speed. Either side of the control may be turned off at l 10 or 1 10a to allow tilting of the spray head about a single axis, or both sides may operate simultaneously. For example, the transverse actuator 60 may be operated at a slow rate and the longitudinal actuator 62 may be operated at a relatively fast rate, such that the spray pattern will sweep progressively over the width and length of the sediment bed.

The apparatus of the present invention is particularly suitable for breaking up and flushing out hardened sediment or cohesive particulate matter. in the case of the tank car shown in FIGS. 1 and 2, an advantageous sequence of cleaning steps would involve the following:

'First. the jet spray is directed at the bottom outlet opening 17 for a sufficient period of time to clear the opening. If desired, a high pressure liquid jet may be di-.

rected into the opening 17 from the exterior of the car. Clearing of the opening prevents an excessive build-up of wash liquid, usually water, in the bottom of the tank, which would otherwise shield the sediment from the jet.

. Thereafter, the longitudinal control may be activated along the centerline of the bed 180, in order to form a longitudinal trench therein for the efficient draining of liquid. The spray jet is then directed to one side of the bed, and both transverse and longitudinal controls are x set in the auto position. The transverse speed is set at a very slow rate, whereas the longitudinal speed is set at a relatively rapid rate. In this manner, the jet is directed at successive longitudinal" sectors of the sediment bed toward the trench formed in the previous step, which causes the sediment to be broken up and to be washed down into the trench and out of the opening.

The liquid jet used in connection with the present invention is therefore distinguishable from rotating low pressure spray nozzles which have been employed in the past to flush the interior of tanks. Such nozzles would be ineffective to break up and clear heavy solid sediments or deposits in tank interiors.

I claim:

1. Cleaning apparatus for vessels comprising pressure jet means, means for rotatably mounting said jet means about first and second different axes, first power means for tilting said jet means about said first axis in both directions, second power means for tilting said jet means about said second axis in both directions, and first and second separate control means connected to respective first and second power means for automatically and independently tilting said jet means back and forth about said first and second axes in respective arcs of spray direction.

2. The apparatus of claim 1 wherein each control means comprises double acting hydraulic means operatively connected to said power means, and includes means for automatically reciprocating said hydraulic means.

3. Cleaning apparatus of claim 1 wherein at least one of said control means includes means for presetting the arc of movement of said jet means between which said jet means is tilted back and forth.

4. The apparatus of claim 2 wherein the means for automatically reciprocating said hydraulic means is responsive to said hydraulic means.

5. The apparatus of claim 4 wherein said hydraulic means includes a reciprocating piston and a part projecting therefrom and movable therewith, and the means for automatically reciprocating said hydraulic means includes a pair of spaced limit valves connected to opposite sides of the piston of said hydraulic means, said limit valves being alternatively actuated by said part. 1 I

6. The apparatus of claim 5 wherein the distance between said limit valves is adjustable to control the degree of movement of said piston in the hydraulic means.

7. Directional control spray apparatus comprising a pressure spray nozzle, power means for moving said nozzle, and control means for controlling movement of said nozzle, said control means comprising reversably acting means connected to said power means and operative to move said nozzle in opposite directions upon reciprocation of said reversably acting means, and means for automatically reciprocating said reversably acting means.

8. The apparatus of claim 7 wherein limiting means are provided for adjustably limiting the degree of reciprocation of said reversably acting means.

9. The apparatus of claim 7 wherein speed control means are provided for controlling the speed of movement of said reversably acting means.

10. The apparatus'of claim 9 wherein said speedcontrol means is automatically variable.

means, said hydraulic means comprising a master cylinder having a reciprocating piston mounted therein and outlets on opposite sides of said piston connected to said power means, and control means for reciprocating said piston and limiting the degree of movement of said piston in either direction, whereby to control the degree of movement of said nozzle about said axis in both directions.

Claims

5. The apparatus of claim 4 wherein said hydraulic means includes a reciprocating piston and a part projecting therefrom and movable therewith, and the means for automatically reciprocating said hydraulic means includes a pair of spaced limit valves connected to opposite sides of the piston of said hydraulic means, said limit valves being alternatively actuated by said part.

10. The apparatus of claim 9 wherein said speed control means is automatically variable.

11. The apparatus of claim 10 wherein said speed control means is operative to decrease the speed of said reversably acting means near the limits of movement thereof.

12. Cleaning apparatus comprising a high pressure spray nozzle movable about an axis, reversible hydraulic power means for moving said nozzle back and forth about said axis, hydraulic means connected to said power means for actuating and reversing said power means, said hydraulic means comprising a master cylinder having a reciprocating piston mounted therein and outlets on opposite sides of said piston connected to said power means, and control means for reciprocating said piston and limiting the degree of movement of said piston in either direction, whereby to control the degree of movement of said nozzle about said axis in both directions.