HYDROVAC WITH SAFE STATE

Abstract

A hydrovac is provided having, an engine, a transmission comprising a power take-off connected to a hydraulic pump, a debris tank, a vacuum hose connected to the debris tank, a boom carrying the vacuum hose, a blower operative to create a vacuum in the debris tank, a hydraulic motor connected to the blower to drive the blower, the hydraulic motor connected to the at least one hydraulic pump, an emergency shutoff valve connected in fluid communication with the debris tank, a boom isolation assembly which in a closed position fluidly isolates the debris tank from the vacuum hose, and a controller. A controller operative to, in response to the controller losing communication with a remote control, open the emergency shutoff valve, close the boom isolation assembly, disengage the power take-off, and after the power take-off is disengaged, slowing a speed of the engine to an idle speed.

Claims

1. A hydrovac comprising: a frame; a cab mounted near a front end of the frame; an engine mounted on the frame; a transmission connected to the engine, the transmission comprising: at least one power take-off, the at least one power take-off connected to at least one hydraulic pump; steering wheels operative to steer the hydrovac; ground wheels connected to the frame and operative to be driven by the engine through the transmission; a debris tank mounted on the frame behind the cab and proximate a rear end of the hydrovac; a vacuum hose fluidly connected to the debris tank, the vacuum hose having a distal end; a boom pivotally mounted at a first end, proximate a rear end of the hydrovac and carrying the vacuum hose; a blower operatively connected to the debris tank and operative to create a vacuum in the debris tank; a hydraulic motor connected to the blower to drive the blower, the hydraulic motor connected to the at least one hydraulic pump; an emergency shutoff valve connected in fluid communication with the debris tank; a boom isolation assembly which in an open position places the debris tank in fluid communication with the vacuum hose and in a closed position fluidly isolates the debris tank from the vacuum hose; a remote control; and a controller, comprising: at least one processing unit; an output interface operatively connectable to the engine, the transmission, the emergency shutoff valve, and the boom isolation assembly; a wireless interface; and, at least one memory containing program instructions, wherein the controller is operative to: in response to the controller losing communication with the remote control, open the emergency shutoff valve; in response to the controller losing communication with the remote control, close the boom isolation assembly; in response to the controller losing communication with the remote control, disengage the at least one power take-off; and after the at least one at least one power take-off is disengaged, slowing a speed of the engine to an idle speed.

2. The hydrovac of claim 1 wherein the controller is further operative to: open the emergency shutoff valve by sending a signal to stop the flow of hydraulic fluid to the emergency shutoff valve.

3. The hydrovac of claim 2 wherein the emergency shut off valve is a normally open hydraulic valve.

4. The hydrovac of claim 1 wherein the transmission comprises: a first power take-off connected to a first hydraulic; and a second power take-off connected to a second hydraulic pump, and wherein the first hydraulic pump and the second hydraulic pump are connected to the hydraulic motor.

5. They hydrovac of claim 1 further comprising a water pump and wherein the controller is further operative to, in response to the controller losing communication with the remote control, stop the water pump.

6. The hydrovac of claim 1 further comprising at least one water tank.

7. The hydrovac of claim 1 wherein the boom isolation assembly comprises: a chamber; an inlet in a bottom of the chamber leading to the debris tank; a first opening leading to the proximal end of the vacuum hose; a second opening on an opposite side of the chamber; a plate sized to fit in the first opening and the second opening; a rod connected to the plate; and an actuator to move the rod and therefore the plate between the first opening, blocking the first opening, and the second opening, blocking the second opening.

8. The hydrovac of claim 1 wherein the emergency shutoff valve is positioned in a vacuum conduit in fluid communication with the debris tank.

9. A controller for controlling the operation of hydrovac comprising: a frame; a cab; an engine mounted on the frame; a transmission connected to the engine, the transmission having at least one power take-off, the at least one power take-off connected to at least one hydraulic pump; steering wheels; ground wheels; a debris tank; a vacuum hose fluidly connected to the debris tank; a boom pivotally mounted at a first end and carrying the vacuum hose; a blower operatively connected to the debris tank and operative to create a vacuum in the debris tank; a hydraulic motor connected to the blower to drive the blower, the hydraulic motor connected to the at least one hydraulic pump; an emergency shutoff valve connected in fluid communication with the debris tank; a boom isolation assembly which in an open position places the debris tank in fluid communication with the vacuum hose and in a closed position fluidly isolates the debris tank from the vacuum hose; and, a remote control, the controller comprising: at least one processing unit; at least one output interface operatively connectable to the engine, the transmission, the emergency shutoff valve, and the boom isolation assembly; a wireless interface; and at least one memory containing program instructions, the at least one processing unit, responsive to the program instructions, operative to: in response to the controller losing communication with the remote control, open the emergency shutoff valve; in response to the controller losing communication with the remote control, close the boom isolation assembly; in response to the controller losing communication with the remote control, disengage the at least one power take-off; and after the at least one power take-off is disengaged, slowing a speed of the engine to an idle speed.

10. The controller of claim 9 wherein the hydrovac has a water pump and wherein the controller is further operative to, in response to the controller losing communication with the remote control, stop the water pump.

Description

DESCRIPTION OF THE DRAWINGS

[0008] A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which:

[0009] FIG. 1 is a perspective view of a hydrovac;

[0010] FIG. 2 is driver side view of the hydrovac of FIG. 1;

[0011] FIG. 3 is a passenger side view of the hydrovac of FIG. 1;

[0012] FIG. 4 is a top view of the hydrovac of FIG. 1;

[0013] FIG. 5 is a rear view of the hyrdovac of FIG. 1;

[0014] FIG. 6 is a schematic illustration of an equipment compartment on the driver side of the hydrovac of FIG. 1;

[0015] FIG. 7 is a schematic illustration of a blower behind the equipment compartment in FIG. 6;

[0016] FIG. 8 is a schematic illustration of an equipment compartment on the passenger side of the hydrovac of FIG. 1;

[0017] FIG. 9 is a schematic view of a cab and transmission of a hydrovac;

[0018] FIG. 10 is a schematic view of the transmission and power take-off powering a blower;

[0019] FIG. 11 is an illustration of a boom isolation assembly;

[0020] FIG. 12 is a schematic illustration of a controller for the hydrovac;

[0021] FIG. 13 is a front view of a remote control for operating a hydrovac; and

[0022] FIG. 14 is a flow chart of a method to stop an operation of a hydrovac in response to losing communication with a remote control.

DETAILED DESCRIPTION

[0023] FIGS. 1-8 illustrate a hydro-evacuation truck or a hydrovac 10 for performing hydro-excuvations. The hydrovac 10 can include: a frame 20; steering wheels 30; ground drive wheels 40; a cab 50; an engine 63; a transmission 65; one or more water tanks 60; a debris tank 70; a boom 80; a vacuum hose 90; a blower 100; a controller 200; a water pump 110; a dig wand 120; and, an emergency shut off valve 170.

[0024] The frame 20 is supported by the steering wheels 30 and the ground wheels 40. The frame 20 supports the various components of the hydrovac 10. The steering wheels 30 are positioned near the front of the frame 20 and operative to steer the hydrovac 10. The ground drive wheels 40 are operative to be driven by the engine 63 and move the frame 20 and therefore the hydrovac 10. The drive wheels 40 can be provided on axles.

[0025] The cab 50 can be mounted near a front end of the frame 20. Referring to FIG. 9, the cab 50 can contain a passenger compartment 52 and a hood 54 enclosing the engine (not shown), such as an internal combustion engine. The engine can be connected to the transmission 65.

[0026] The steering wheels 30 can be steered from the passenger compartment 52 of the cab 50 and the transmission 65 can be connected to the axles of the ground wheels 40 to drive the ground wheels 40 and move the hydrovac 10.

[0027] Referring to FIG. 10, the transmission 65 can also contain power take-offs (PTOs) 57A, 57B. The first PTO 57A can be connected to a first hydraulic pump 58A and the second PTO 57B can be connected to a second hydraulic pump 58B that routes hydraulic fluid through hydraulic lines 59 to a hydraulic motor 102 that powers the blower 100. When the PTOs 57A, 57B are engaged, the speed of the engine 63 will determine how fast the PTOs 57A, 57B turn and therefore the rpms of the hydraulic pumps 58A, 58B. The faster the hydraulic pumps 58A, 58B are rotated, the greater the flow the of hydraulic fluid flowing through the hydraulic fluid lines 59 to the hydraulic motor 102 and the faster the hydraulic motor 102 is driven. The hydraulic motor 102 drives the blower 100, so the faster the hydraulic motor 102 is rotated by the hydraulic fluid, the faster the blower 100 operates.

[0028] Referring again to FIGS. 1-8, the debris tank 70 can be mounted on the frame 20 behind the cab 50 with a rear end of the debris tank 70 positioned proximate a rear end of the hydrovac 10. The debris tank 70 can be used to store the soil and water slurry vacuumed up by the hydrovac 10. The debris tank 70 allows the slurry vacuumed up by the hydrovac 10 to be stored in the hydrovac 10 during its operation and then transported by the hydrovac 10 in the debris tank 70 to a dump site for disposal when the excavation is complete or the debris tank 70 is full. Referring to FIG. 5, the debris tank 70 can have a drain door 72 at the rear end of the debris tank 70 which can be opened to allow the debris tank 70 to be emptied or dumped out.

[0029] Referring again to FIGS. 1-8, the debris tank 70 can be provided with hydraulics so that a front end of the debris tank 70 can be lifted upwards, slanting the debris tank 70 downwards towards its rear end to aid dumping out the debris tank 70.

[0030] The boom 80 can be mounted proximate the rear end of the hydrovac 10 to carry the vacuum hose 90 and to maneuver the vacuum hose 90 to a side of the hydrovac 10 and in some cases even pivot the boom 80 around behind the hydrovac 10. In one aspect, the boom 80 can only maneuver the vacuum hose 90 to one side of the hyrovac 10, such as the passenger side of the hydrovac 10. The boom 80 allows the vacuum hose 90 to be maneuvered into a desired positioned to allow the vacuum hose 90 to suck up soil and any rocks or other debris that have been liquified into a slurry. The boom 80 can be pivotally mounted at a first end 82 so that the boom 80 can be pivoted from side to side around is first end 82 as well as being pivoted upwards and downwards around the first end 82 of the boom 80. A second end 84 of the boom 80 can be curved downwards to direct the vacuum hose 90 downwards towards a ground surface being excavated.

[0031] In one aspect, the boom 80 might have an extendable section 86 that allows the length of the boom 80 to be extendable and retractable to better enable an operator to maneuver the second end 84 of the boom 80 and therefore the vacuum hose 90 to a desired position.

[0032] The vacuum hose 90 can have a distal end 92. With a portion of the vacuum hose 90 supported by the boom 80 and running along the boom 80, the distal end 92 of the vacuum hose 90 extends past the second end 84 of the boom 80 so that the distal end 92 of the vacuum hose 90 can be directed downwards towards the ground surface. An operator can position the distal end 92 of the vacuum hose 90 where they desire by pivoting the boom 80 from side to side and up and down.

[0033] When the hydrovac 10 is not in use or is going to be transported to another location, the boom 80 can be placed in a transport position with the boom 80 swung over top of the hydrovac 10, so that the second end 84 of the boom 80 and the vacuum hose 90 do not extend past the sides of the hydrovac 10. The boom 80 can be pivoted downward to be positioned against a top of the hydrovac 10.

[0034] The vacuum hose 90 can be flexible to allow it to bend so that it can bend as it is maneuvered by the boom 80 and bend downwards around the curved second end 84 of the boom 90 so that the distal end 92 of the vacuum hose 90 points downwards towards a ground surface to be excavated.

[0035] A dig tube (not shown) made of a rigid material, like aluminum, etc. can be attachable to the distal end 92 of the vacuum hose 90. This rigid dig tube can prevent damage and deformation to the vacuum hose 90 because it will be the dig tube that comes directly into contact with the liquified soil and other debris and is vacuumed up the dig tube first before the slurry enters then the vacuum hose 90 connected to the dig tube.

[0036] In one aspect, a portion of the vacuum hose 90 can be flexible while another portion of the vacuum hose 90 might be formed of rigid tubing, made of a rigid material such as metal. For example, a portion of the vacuum hose 90 that extends past the second end 84 of the boom 80 could be flexible tubing, while a portion of the vacuum hose 90 that runs along the boom 80 could be rigid tubing.

[0037] Referring to FIG. 7, the blower 100 can be used to create a vacuum in the debris tank 70. The vacuum hose 90 can be in fluid communication with the debris tank 70 and by creating a vacuum in the debris tank 70 suction will be created in the vacuum hose 90, allowing the vacuum hose 90 to suck a soil and water slurry through the vacuum hose 90 and into the debris tank 70. Referring again to FIG. 10, the blower 100 can be driven by the hydraulic motor 102 that is supplied with hydraulic fluid from hydraulic pumps 58A, 58B which in turn are driven off the first PTO 57A and the second PTO 57B of the transmission 65. The faster the blower 100 is driven, the more vacuum that is created by the blower 100.

[0038] Referring again to FIGS. 1-8, a boom isolation assembly 130 can be provided at the first end 82 of the boom 80 and at a proximal end 94 of the vacuum hose 90 to isolate the vacuum hose 90 from the debris tank 70 and cut off suction created in the vacuum hose 90 from a vacuum in the debris tank 70. Referring to FIG. 11, the boom isolation assembly 130 can have: a chamber 132 with an inlet 134 in the bottom leading to the debris tank 70; a first opening 136 leading to the proximal end 94 of the vacuum hose 90; a second opening 138 on the opposite side of the chamber 132; a plate 140 sized to fit in the first opening 136 and the second opening 138; a rod 142 connected to the plate 140; and an actuator 139 (shown in FIGS. 2-4), such as a hydraulic cylinder, to move the rod 142 and therefore the plate 140 between the first opening 136, blocking the first opening 136, and the second opening 138, blocking the second opening 138.

[0039] During operation of the hydrovac 10, the boom isolation assembly 130 can be in an open position placing the debris tank 70, and a vacuum created in the debris tank 70, through the inlet 134, in fluid communication with the vacuum hose 90 and creating suction in the vacuum hose 90. The actuator 139 can be retracted, moving the plate 140 into the second opening 138 and placing the vacuum in the debris tank 70 in fluid communication with the vacuum hose 90, creating suction in the vacuum hose 90 and allowing rock, soil slurry and other debris to be sucked through the vacuum hose 90, through the inlet 134 in the chamber 132, and into the debris tank 70. Debris sucked through the vacuum hose 90 will enter the chamber 132 through the first opening 136, some of which can slam into opposite wall of the chamber 132 and the plate 140 positioned in the second opening 138 and fall through the inlet 134, into the debris tank 70.

[0040] Closing the boom isolation assembly 130 can isolate the debris tank 70 from the vacuum hose 90, stopping a vacuum in the debris tank 70 from creating a suction in the vacuum hose 90 and stopping the vacuum hose 90 from sucking debris and other objects into the vacuum hose 90. The actuator 139 can be extended so that the plate 140 is moved from the second opening 138 to the first opening 136, blocking the first opening 136 leading to the distal end 94 of the vacuum hose 90. This will fluidly isolate the vacuum in the debris tank 70 from the vacuum hose 90, stopping suction in the vacuum hose 90.

[0041] FIG. 6 shows the position of the emergency shutoff valve 170 provided in a vacuum conduit 172. The vacuum conduit 172 is in fluid communication with the debris tank 70. The emergency shutoff valve 170 can be a normally open hydraulic valve so that emergency shutoff valve 170 is opened when not supplied with hydraulic fluid. The emergency shutoff valve 170 can have a biasing member, such as a spring, to place the emergency shutoff valve 170 in an open position, venting the vacuum conduit 172 and the debris tank 70 to atmosphere. To create suction, hydraulic fluid can be routed to the emergency shutoff valve 170 to overcome the biasing member and close the emergency shutoff valve 170. When the blower 100 is running, vacuum will be created in the vacuum conduit 172 and thereby suction in the vacuum hose 90 when the emergency shutoff valve 170 is closed.

[0042] When hydraulic fluid flow is stopped to the emergency shutoff valve 170, the biasing member will no longer be acted against by the hydraulic fluid and the biasing member will then force the emergency shutoff valve 170 open, venting the vacuum in the vacuum conduit 172 and the debris tank 70 to atmosphere and reducing or even stopping suction in the vacuum hose 90, even if the blower 100 is still running.

[0043] Referring again to FIGS. 1-8, the water tanks 60 can be provided on the hydrovac 10 to supply water to the water pump 10 where the water will be pressurized and routed to the dig wand 120. The dig wand 120 can be connected to the hydrovac 10 with a hose 122 to provide pressurized water from the water tanks 60 and the water pump 110 to the dig wand 120.

[0044] Referring to FIG. 8, the controller 200 can be used to control various components on the hydrovac 10. In one aspect, the controller 200 can control the operation of the blower 100, the water pump 110, the boom 80, the revolutions per minute (RPM) of the engine 63 and the transmission 65.

[0045] FIG. 12 is a schematic illustration of the controller 200, in one aspect. The controller 200 can include a processing unit 202, such as a microprocessor, that is operatively connected to a computer readable memory 204 and can control the operation of controller 200. Program instructions 206, for controlling the operation of the processing unit 202, can be stored in the memory 204 as well as any additional data needed for the operation of the controller 200.

[0046] A human machine interface 255, such as a touchpad, display, and/or keypad, can be used by a user to interact with the controller 200.

[0047] A control panel 250 can be used to allow an operator to monitor the operation of the controller 200 and control its operation.

[0048] An input interface 220 can be provided operatively connected to the processing unit 202 so that the controller 200 can receive signals from external sensors.

[0049] Referring to FIGS. 1-8 and 12, an output interface 222 can be provided operatively connected to the processing unit 202 to send signals to other components on the hydrovac 10. The output interface 222 can be connected to engine 63 to control various aspects of the operation of the engine 63, such as the RPM of the engine 63, and the transmission 65 to control when the PTOs 57A, 57B are engaged by the transmission 65. By controlling when the PTOs 57A, 57B are engaged by the transmission 65, the controller 200 can control when the blower 100 is operating. The output interface 222 can also be connected to the water pump 110 to control when the water pump 110 is activated.

[0050] The output interface 222 can be connected to the boom 80 to control the operation of the boom 80 as well as the emergency shutoff valve 170, the actuator 139, the water pump 110, the engine 63, and the transmission 65, as well as other components on the hydrovac 10.

[0051] The input interface 320 can be used to receive signals from the various components on the hydrovac 10 to determine the status and operation of these components.

[0052] A wireless interface 224 can be used to allow a remote control to wirelessly connected to the controller 200 and allow the remoted control to control the operation of various components on the hydrovac 10 through the controller 200.

[0053] Referring to FIG. 8, the control panel 250 (and optionally the controller 200) can be located in a storage compartment 260 on a side of the hydrovac 10 for easy access by an operator. The storage compartment 260 can have doors 262 to enclose the control panel 250 when access is not required. The storage compartment 260 can also house the water pump 110 and store a remote control, that controls the operation of the hydrovac 10, when it is not required and, optionally, other components.

[0054] The movement of the boom 80, the operation of the blower 100, creating suction in the vacuum hose 90, and the water pump 110, can be controlled by a remote control that communicates with the controller 200 through the wireless interface 224. FIG. 13 illustrates a remote control 300 that can be used to control the operation of the hydrovac 10 by connecting through the wireless connection 224 of the controller 200 and controlling various components of the hydrovac 10 through the controller 200. In one aspect, the remote control 300 can have: a power on button 301; a boom up button 302; a boom down button 304; a rotate boom counter-clockwise button 306; a rotate boom clockwise button 308; a boom retract button 312; a boom extend button 314; a boom isolation button 316; an eco mode button 318; a water system on/off button 322; a water system pressure increase/decrease button 324; and, an emergency stop button 330. The various buttons can be used to control the operation of the hydrovac 10.

[0055] The remote control 300 may also contain one or more display screens for displaying information about the operation of the hydrovac 10, such as a levels screen 340, showing the level of water in the water tanks 60 and the level of debris in the debris tank 70, and a water system pressure screen 350 showing the pressure of the water in the system pressurized by the water pump 110.

[0056] Referring to FIGS. 1-8, in operation, the hydrovac 10 can be driven to a location where excavation is required. At the location, an operator can park the hydrovac 10 adjacent to where the excavation will occur and exit the hydrovac 10 to begin the hydro-evacuation process. The operator can then move the boom 80 to maneuver the vacuum hose 90 (such as with the remote control 300) over to one side of the hydrovac 10 towards the soil to be excavated and attach a dig tube to the distal end 92 of the vacuum hose 90. The operator can then maneuver the distal end 92 of the vacuum hose 90 and the attached dig tube over the soil to be excavated.

[0057] If the soil to be excavated is not already liquified to create a slurry that can be vacuumed up the vacuum tube 90, the operator can use the dig wand 120 and pressurized water supplied from the water tanks 60 by the water pump 110 to spray the pressurized water into the soil to liquify the soil and create a vacuumable slurry.

[0058] The operator can then start the blower 100 to create a vacuum in the vacuum hose 90 and direct the distal end 92 of the vacuum hose 90 towards the liquified soil to vacuum the soil slurry up through the vacuum hose 90 and into the debris tank 70.

[0059] When the excavation is complete or the debris tank 70 is full, the operator can stop spraying water with the dig wand 120 and stop the blower 100 from creating a vacuum in the vacuum hose 90. They can then disconnect the dig tube 95 from the distal end 92 of the vacuum hose 90 and maneuver the boom 80 to position the boom 80 and the vacuum hose 90 back over the hydrovac 10 and place it in a transport position. With everything stowed away on the hydrovac 10, the hydrovac 10 can be driven to a dump site and the debris tank 70 emptied.

[0060] If the debris tank 70 has hydraulics, the debris tank 70 the drain door 72 can be opened and the debris tank 70 tilted to dump out the contents of the debris tank 70 at the dump site.

[0061] Typically, during excavation operations of the hydrovac 10 an operator will be standing near or even beside the vacuum hose 90, controlling the operation of the hydrovac 10, such as the suction, movement of the boom 80, etc. with the remote control 300. This remote control 300 can be in communication with the controller 200 through the wireless interface 224. However, if for any reason the remote control 300 loses connection with the controller 200, the operator will be unable to control the operation of the hydrovac 10 causing a potentially dangerous situation. Lost communication can occur when the remote control 300 gets too far from the controller 200, the batteries of the remote control 300 run out, signal interface, etc.

[0062] FIG. 14 illustrates of a flowchart of a method for stopping the operation of the hydrovac 10 if communication with the remote control 300 is lost. However, rather than providing an instantaneous shut down/stop of various systems on the hydrovac 10, which could damage the components or increase wear decreasing their service life, various components on they hydrovac 10 can be sequentially de-energized/deactivated to protect the operator and/or the surroundings, eventually placing the hydrovac 10 in a safe state. Th method shuts down specific functions of the hydrovac 10 without turning off the hydrovac 10 and specifically its engine 63, allowing hydraulic pressure to be maintained so that the boom 80 is frozen in place.

[0063] When the remote control 300 re-establishes communication with the controller 200, the systems on the hydrovac 10 can be more easily brought back into operation than if the hydrovac 10 and its engine 63 were stopped.

[0064] The remote control 300 can be in communication with the controller 200 through the wireless interface 224. However, if at any time this communication with the remote control 200 is lost, the controller can move to step 502 of the method and shut down the vacuum operation. This can be done by the controller 200 opening the emergency shut off valve 170. Opening the emergency shut off valve 170 will shut down the vacuum operation of the hydrovac 10 by venting the debris tank 70 and a vacuum created in the debris tank 70 to atmosphere.

[0065] With the controller 200 losing communication with the remote control 300, the processing unit 202 of the controller 200 can send a signal through the output interface 222 to stop the flow of hydraulic fluid to the emergency shutoff valve 170. This stopping of the hydraulic fluid flow will remove the force on the emergency shutoff valve 170 that is overcoming the biasing member, causing the emergency shut off valve 170 to open and the debris tank 70 to be vented to atmosphere, thereby decreasing the suction in the system and specifically in the vacuum hose 90.

[0066] After the emergency shut off valve 170 is opened at step 502, the method can move onto step 504 and close the boom isolation assembly 130 to isolate any vacuum created in the debris tank 70 from the vacuum hose 90, thereby further reducing or stopping any suction in the vacuum hose 90.

[0067] The processing unit 202 can send a signal through the output interface 222 to use the actuator 139 to close the boom isolation assembly 130. Closing the boom isolation assembly 130 will fluidly isolate the vacuum hose 90 from the debris tank 70 and the vacuum created in the debris tank 70 by the blower 100. This will stop suction in the vacuum hose 90.

[0068] At step 506, the wash system can be de-energized by turning off the water pump 110. The processing unit 202 can send a signal, using the output interface 222 to stop the flow of hydraulic fluid to the water pump 110, thereby stopping the water pump 110 supplying pressurized fluid to the dig wand 120.

[0069] At step 508, the controller 200 can de-energize the air system. To de-energize the air system, the PTOs 57A, 57B can be disengaged using the transmission 65 and stop the PTOs 57A, 57B from rotating the hydraulic pumps 58A, 58B connected to the PTOs 57A, 57B, thereby depressurizing the hydraulic fluid in the system and stopping the flow of hydraulic fluid hydraulic motor 102 that is driving the blower 100.

[0070] The controller 200 can send a signal to the transmission 65 to disengage the PTOs 57A, 57A through the output interface 222.

[0071] After, the PTOs 57A, 57B have been disengaged at step 508, the method can move to step 510 and reduce the speed of the engine 63 of the hydrovac 10 to an idle rpm. The processing unit 202 can send a signal through the output interface 222 to reduce a speed of the engine 63 to an idle rpm. If the air system was energized at step 508, a delay, such as 1000 ms can be used before the controller 200 moves form step 508 to 510.

[0072] Optionally, at step 512, the controller 200 can disable all remaining controls of the hydrovac 10.

[0073] With the method finished, the hydrovac 10 can remain in the safe state with the engine 63 of the hydrovac 10 running, but at an idle RPM, and its systems shut down. Once the remote control 300 re-establishes communication with the controller 200, the hydrovac 10 can be brought back to normal operation, being controlled with the remote control 300.

[0074] In one aspect, the operator must go through a pairing procedure to re-establish communication between the remote control 300 and the controller 200.

[0075] The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.