Patent Description:
Hydro vacuum excavation involves directing high pressure water at an excavation site while removing cut earthen material and water by a vacuum system. Sites may be excavated to locate utilities or to cut trenches. The spoil material is removed by entraining the spoil material in an airstream generated by the vacuum system. The spoil material is stored on a vehicle for transport for later disposal of the spoil material. Spoil material is conventionally landfilled or dumped at a designated disposal site. Landfill disposal of spoil material containing a large amount of water may be relatively expensive. Further, tightening regulations may limit disposal options for such slurries.

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. <CIT> describes a drilling fluid reclaimer. The reclaimer has at least one adjustable screen assembly for providing a leveling filter for reclaimed drill fluid. Used drill fluid is placed at the screen assembly at the front the of the screen assembly. A second screen is provided for additional filtering. Drilling fluid passing through the screen is "reclaimed" for use with a drilling system.

The presently claimed invention is directed to a hydro excavation vacuum apparatus for excavating earthen material as specified in claim <NUM>. The apparatus includes a wand for directing pressurized water toward earthen material to cut the earthen material. The wand includes a rotary nozzle for directing water in a rotating, circular path toward the earthen material at an excavation site. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site in an airstream. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. An airlock receives material from the separation vessel and discharges the material through an airlock outlet. The apparatus includes a dewatering system for separating water from cut earthen material discharged from the airlock outlet. The dewatering system includes a slat assembly that receives material from the outlet of the airlock. The pre-screen has openings for separating material from the separation vessel by size. The dewatering system includes a vibratory screen for separating material that passes through the pre-screen by size. The vibratory screen has openings sized smaller than the openings of the pre-screen.

Another aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material. The apparatus includes a wand for directing pressurized water toward earthen material at an excavation site to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site in an airstream. The vacuum is capable of generating a vacuum of at least 61kPa (<NUM>" Hg) at <NUM> cubic meters (<NUM> cubic feet) per minute. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. An airlock receives material discharged from the separation vessel and discharges the material through an airlock outlet. The apparatus includes a dewatering system for separating water from cut earthen material discharged from the airlock outlet. The dewatering system includes a pre-screen that receives material from the separation vessel. The pre-screen has openings for separating material from the separation vessel by size. The dewatering system includes a vibratory screen for separating material that passes through the pre-screen by size. The vibratory screen has openings with a size smaller than the size of the openings of the pre-screen. A ratio of the size of the openings of the pre-screen to the size of the openings of the vibratory screen is at least about <NUM>:<NUM>.

Yet a further aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from an excavation site in an airstream. The apparatus includes a deceleration system for collecting cut earthen material and water from the airstream. The deceleration system includes a deceleration vessel adapted to reduce a velocity of the airstream to allow material to fall from the airstream. The deceleration vessel has an inlet and a spoil material outlet disposed below the inlet. The deceleration system includes a deflection plate disposed within the deceleration vessel for directing material in the airstream downward toward the spoil material outlet. The apparatus includes a dewatering system for separating water from cut earthen material removed from the excavation site.

Yet another aspect of the present disclosure is directed to a vacuum excavation apparatus for excavating earthen material. The apparatus includes a vacuum system for removing cut earthen material from an excavation site in an airstream. The apparatus includes a deceleration system for collecting cut earthen material from the airstream. The deceleration system includes a deceleration vessel adapted to reduce a velocity of the airstream to allow material to fall from the airstream. The deceleration vessel has a vertical axis and an inlet and a spoil material outlet disposed below the inlet. The deceleration system includes a deflection plate disposed within the deceleration vessel for directing material in the airstream downward toward the spoil material outlet. The deflection plate has a material-engaging face having a longitudinal plane. The longitudinal plane of the material-engaging face forms an angle with the vertical axis of the vessel.

Yet another aspect of the present disclosure is directed to a method for hydro excavating a site with an excavation apparatus. The excavation apparatus includes an excavation fluid pump, a separation vessel and a dewatering system. The excavation fluid pump is operated to direct pressurized water toward an excavation site. The pressurized water cuts earthen material. Cut earthen material and water are removed from the excavation site in an airstream and into the separation vessel. The cut earthen material and water separate from the airstream and fall toward an airlock disposed below the separation vessel. The airstream has an average dwell time of less than about <NUM> seconds in the separation vessel. Material discharged from the airlock outlet is introduced into the dewatering system. The dewatering system separates water from cut earthen material removed from the excavation site.

In a further aspect of the present disclosure, a hydro excavation vacuum apparatus for excavating earthen material includes a wand for directing pressurized water toward earthen material to cut the earthen material. An excavation fluid pump supplies fluid to the wand to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site and a dewatering system for separating water from cut earthen material removed from the excavation site. The apparatus includes a fluid storage and supply system which receives water from the dewatering system. The fluid storage and supply system includes a first vessel in fluid communication with the excavation fluid pump and a first vessel level sensor for sensing the fluid level in the first vessel. The fluid storage and supply system includes a second vessel. The second vessel is in fluid communication with the dewatering system to receive water discharged from the dewatering system. The fluid storage and supply system includes a second vessel level sensor for sensing the fluid level in the second vessel and a second vessel transfer pump for transferring fluid from the second vessel.

In another aspect of the present disclosure a hydro excavation vacuum apparatus for excavating earthen material includes a wand for directing pressurized water toward earthen material to cut the earthen material. An excavation fluid pump supplies fluid to the wand to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site. The apparatus includes a dewatering system for separating water from cut earthen material removed from the excavation site. The apparatus includes a fluid storage and supply system. The fluid storage and supply system includes a first vessel in fluid communication with the excavation fluid pump. The fluid storage and supply system includes a second vessel. The second vessel is in fluid communication with the dewatering system to receive fluid discharged from the dewatering system. The fluid storage and supply system includes a third vessel for receiving fluid from the second vessel.

An aspect of the present disclosure is directed to a method for hydro excavating a site with an excavation apparatus having at least two vessels for supplying and storing excavation fluid. Maiden water is provided in a first vessel of the apparatus. The maiden water is at an initial level. Pressurized maiden water from the first vessel is directed toward an excavation site. The pressurized water cuts earthen material. Cut earthen material and first cycle water are removed from the excavation site. First cycle water is separated from the cut earthen material. The first cycle water is introduced into a second vessel. Additional maiden water is introduced into the first vessel upon the maiden water level in the first vessel being reduced to below the initial level or less.

In another aspect of the present disclosure directed to a hydro excavation vacuum apparatus for excavating earthen material, the apparatus includes a wand for directing pressurized water toward earthen material to cut the earthen material. An excavation fluid pump supplies fluid to the wand to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site. The apparatus includes a dewatering system for separating water from cut earthen material removed from the excavation site. The apparatus includes a fluid storage and supply system which receives water from the dewatering system. The fluid storage and supply system includes a first vessel and a second vessel. The second vessel is in fluid communication with the dewatering system to receive water discharged from the dewatering system. The fluid storage and supply system includes a third vessel and a valving system for switching the source of water directed through the wand from the first vessel to the second vessel.

Yet a further aspect of the present disclosure is directed to a method for hydro excavating a site with an excavation apparatus having at least two vessels for supplying and storing excavation fluid. Maiden pressurized water from a first vessel is directed toward one or more excavation sites. The first vessel has a volume. The pressurized water cuts earthen material. The volume of maiden pressurized water used for excavation is at least the volume of the first vessel. Cut earthen material and first cycle water are removed from one more excavation sites. First cycle water is separated from the cut earthen material. The first cycle water is introduced into a second vessel. Additional maiden pressurized water is directed toward one or more excavation sites after the volume of the maiden pressurized water used for excavation is at least the volume of the first vessel.

In another aspect of the present disclosure directed to an airlock for conveying material, the airlock includes a plurality of rotatable vanes that form pockets to hold and convey material. The vanes rotate from an airlock inlet to an airlock outlet along a conveyance path. The airlock includes a housing. The housing has a first sidewall, a second sidewall, and an outer annular wall that extends from the first sidewall to the second sidewall. The airlock outlet extends through the outer annular wall. The airlock outlet tapers outwardly from a vertex toward at least one sidewall.

In a further aspect of the present disclosure directed to a method for hydro excavating a site with an excavation apparatus, pressurized water is directed toward an excavation site. The pressurized water cuts earthen material. Cut earthen material and water are removed from the excavation site and into a separation vessel. The cut earthen material and water separate from the airstream and fall toward an airlock disposed below the separation vessel. The airlock has rotating vanes that form pockets to receive cut earthen material and water. The airlock has less than <NUM> vanes. The vanes of the airlock are rotated at a speed of less than <NUM> RPM to move cut earthen material and water from an airlock inlet toward an airlock outlet. Material discharged from the airlock outlet is introduced into a dewatering system. The dewatering system separates water from cut earthen material removed from the excavation site.

Another aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material. The apparatus includes a wand for directing pressurized water toward earthen material to cut the earthen material. The wand includes a rotary nozzle for directing water in a rotating, circular path toward the earthen material at an excavation site. The apparatus includes a vacuum pump for removing cut earthen material and water from the excavation site in an airstream. The vacuum pump is a positive displacement pump. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. An apparatus includes a conduit for conveying water and cut earthen material from the excavation site to the separation vessel. The conduit has a diameter D<NUM>. An airlock receives material from the separation vessel and discharges the material through an airlock outlet. The airlock includes vanes with pockets disposed between adjacent vanes. The vanes are sized to receive particles with a diameter D<NUM> or greater.

An additional aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material at an excavation site. The apparatus has a lateral axis and includes a wand for directing pressurized water toward earthen material to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site in an airstream. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. An airlock receives material from the separation vessel and discharges the material through an airlock outlet. The apparatus includes a dewatering system for separating water from cut earthen material. The dewatering system includes at least one screen for separating material by size. The apparatus includes an adjustment system for adjusting a pitch or a roll of the screen. The adjustment system includes an actuator for adjusting the pitch and/or the roll of the screen and a pivot member for adjusting the pitch or the roll of the screen. The pivot member is aligned with the airlock outlet relative to the lateral axis.

An aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material at an excavation site. The apparatus has a longitudinal axis and includes a wand for directing pressurized water toward earthen material to cut the earthen material. The apparatus includes vacuum system for removing cut earthen material and water from the excavation site in an airstream. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. An airlock receives material from the separation vessel and discharges the material through an airlock outlet. The apparatus includes a dewatering system for separating water from cut earthen material. The dewatering system includes at least one screen for separating material by size. The screen has a rear toward which material is loaded onto the screen from the airlock outlet and a front toward which material is discharged from the screen. The screen has a center plane midway between the rear and the front. The apparatus incudes an adjustment system for adjusting a pitch or a roll of the screen. The adjustment system includes an actuator for adjusting the pitch or the roll of the screen. The adjustment system includes a pivot member for adjusting the pitch and/or the roll of the screen. The pivot member is rearward to the center plane of the screen relative to the longitudinal axis.

In yet another aspect of the present disclosure directed to a hydro excavation vacuum apparatus for excavating earthen material, the apparatus has a longitudinal axis and includes a wand for directing pressurized water toward earthen material to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from the excavation site in an airstream. The apparatus includes a separation vessel for removing cut earthen material and water from the airstream. The apparatus includes an airlock that receives material from the separation vessel and discharges the material through an airlock outlet. The apparatus includes a dewatering system for separating water from cut earthen material. The dewatering system includes at least one screen for separating material by size. An adjustment system for adjusting a pitch and a roll of the screen includes an actuator for adjusting the pitch or the roll of the screen. The adjustment system includes a pivot member for adjusting the pitch and the roll of the screen. The pivot member includes a first portion to adjust the roll of the screen and a second portion to adjust the pitch of the screen.

Yet a further aspect of the present disclosure is directed to a cyclonic separation system for separating material entrained in an airstream. The system includes one or more cyclones for separating material from the airstream. The one or more cyclones have a solids outlet. The system includes a sealed conveyor with the one or more cyclones discharging material directly into the conveyor through the solids outlet. The system includes a discharge pump with the sealed conveyor discharging material into the discharge pump.

Yet another aspect of the present disclosure is directed to a hydro excavation vacuum apparatus for excavating earthen material. The apparatus includes a wand for directing pressurized water toward earthen material to cut the earthen material. An excavation fluid pump supplies fluid to the wand to cut the earthen material. The apparatus includes a vacuum system for removing cut earthen material and water from an excavation site and includes a dewatering system for separating water from cut earthen material removed from the excavation site. The apparatus includes a fluid storage and supply system that receives water from the dewatering system. The fluid storage and supply system includes a discharge manifold for offloading water from the fluid storage and supply system. The system includes a first vessel and a second vessel. The second vessel is in fluid communication with the dewatering system to receive water discharged from the dewatering system. The system includes a transfer pipe for transferring fluid from the first vessel to an excavation fluid pump. The system includes a valve for selectively directing fluid from the first vessel between (<NUM>) the transfer pipe and (<NUM>) the discharge manifold.

Yet a further aspect of the present disclosure is directed to a method for filling a fluid storage and supply system of a hydro vacuum excavation apparatus. The fluid storage and supply system includes a first vessel, a second vessel for receiving water from a dewatering system, a third vessel, and a manifold connected to the first, second and third vessels. Water is added to the first vessel. One or valves are actuated such that the first vessel is in fluid communication with the manifold and the third vessel is in fluid communication with the manifold. A first vessel transfer pump is operated to transfer water from the first vessel, into the manifold and into the third vessel.

Various refinements exist of the features noted in relation to the above-mentioned aspects of the present disclosure. Further features may also be incorporated in the above-mentioned aspects of the present disclosure as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments of the present disclosure may be incorporated into any of the above-described aspects of the present disclosure, alone or in any combination.

An example hydro excavation vacuum apparatus <NUM> for excavating earthen material is shown in <FIG>. As described in further detail herein, the hydro excavation vacuum apparatus <NUM> is used to excavate a site by use of a jet of high pressure water expelled through a wand. The cut earthen material and water are removed by a vacuum system and are processed onboard the apparatus by separating the cut earthen material from the water. Processed water may suitably be used for additional excavation or disposed. Recovered earthen material may be used to backfill the excavation site or disposed.

The hydro excavation vacuum apparatus <NUM> may include a chassis <NUM> which supports the various components (e.g., vacuum system, separation vessel, airlock and/or dewatering system) with wheels <NUM> connected to the chassis <NUM> to transport the apparatus <NUM>. The apparatus <NUM> may be self-propelled (e.g., with a dedicated motor that propels the apparatus) or may be adapted to be towed by a separate vehicle (e.g., may include a tongue and/or hitch coupler to connect to the separate vehicle).

The hydro excavation vacuum apparatus <NUM> includes a dedicated engine <NUM> that powers the various components such as the excavation pump, vacuum pump, vibratory screens, conveyors and the like. In other embodiments, the engine <NUM> is eliminated and the apparatus is powered by a motor that propels the apparatus or the apparatus <NUM> is powered by other methods.

The apparatus <NUM> includes a front <NUM>, rear <NUM>, and a longitudinal axis A (<FIG>) that extends through the front <NUM> and rear <NUM> of the apparatus <NUM>. The apparatus <NUM> includes a lateral axis B that is perpendicular to the longitudinal axis A.

The hydro excavation vacuum apparatus <NUM> includes a wand <NUM> (<FIG>) for directing pressurized water W toward earthen material to cut the earthen material. The wand <NUM> is connected to an excavation fluid pump <NUM> that supplies water to the wand <NUM>. The pump <NUM> may supply a pressure of, for example, at least about <NUM>,<NUM> kPa (<NUM> psi) or at least about <NUM>,<NUM> kPa (<NUM>,<NUM> psi) (e.g., from about <NUM>,<NUM> kPa to about <NUM>,<NUM> kPa (<NUM>,<NUM> psi to about <NUM>,<NUM> psi) or from <NUM>,<NUM> kPa to about <NUM>,<NUM> kPa (<NUM>,<NUM> psi to about <NUM>,<NUM> psi)).

In some embodiments, the wand <NUM> includes a rotary nozzle <NUM> (<FIG>) for directing water W toward the earthen material to cut the earthen material. Generally, any rotary nozzle that causes the water to be directed toward the earthen material in a circular path at the site of the excavation may be used. Such rotary nozzles may include a rotor insert with blades that rotate around a longitudinal axis of the nozzle when water is forced through the nozzle. The rotor insert may include three or more channels that force fluid to flow in different pathways through the rotor insert to cause the water to move along a circular path as it contacts the excavation material (i.e., the water moves within a cone that extends from the nozzle toward the excavated material). In other embodiments, a straight tip nozzle that directs fluid along a straight path in a concentrated jet may be used.

The hydro excavation vacuum apparatus <NUM> includes a vacuum system <NUM> (<FIG>) for removing spoil material from the excavation site. Spoil material or simply "spoils" may include, without limitation, rocks, cut earthen material (e.g., small particulate such as sand to larger pieces of earth that are cut loose by the jet of high pressure water), slurry, and water used for excavation. The spoil material may have a consistency similar to water, a slurry, or even solid earth or rocks. The terms used herein for materials that may be processed by the hydro excavation vacuum apparatus <NUM> such as, for example, "spoils," "spoil material," "cut earthen material" and "water", should not be considered in a limiting sense unless stated otherwise.

The vacuum system <NUM> includes a boom <NUM> that is capable of rotating toward the excavation site to remove material from the excavation site. The boom <NUM> may include a flexible portion <NUM> (<FIG>) that extends downward to the ground to vacuum spoil material from the excavation site. The flexible portion <NUM> may be manipulated by a user to direct the vacuum suction toward the excavation site.

The vacuum system <NUM> acts to entrain the cut earth and the water used to excavate the site in a stream of air. A blower or vacuum pump <NUM> (<FIG>) pulls a vacuum through the boom <NUM> to entrain the material in the airstream. Air is discharged from the blower <NUM> after material is removed from the airstream.

The airstream having water and cut earth entrained therein is pulled through the boom <NUM> and through a series of conduits (e.g., conduit <NUM> shown in <FIG>) and is pulled into a separation vessel <NUM>, described further below. The separation vessel <NUM> removes at least a portion of cut earthen material and water from the airstream. Air exits one or more separation vessel air outlets <NUM> and is introduced into cyclones <NUM> (<FIG>) to remove additional spoil material (e.g., water, small solids such as sand, low density particles such as sticks and grass, and the like) not separated in the separation vessel <NUM>. Material that collects in the bottom of the cyclones <NUM> is conveyed by a cyclone discharge pump <NUM> (<FIG>) (e.g., peristaltic pump described in further detail below) or, alternatively, is gravity fed to the dewatering system <NUM> described below. The air removed from the cyclones <NUM> is introduced into one or more filter elements before entering the vacuum pump <NUM>. The vacuum pump <NUM> may be disposed in or near the engine compartment <NUM> (<FIG>). Air is removed from the apparatus through a vacuum exhaust <NUM>.

The vacuum pump <NUM> generates vacuum in the system to pull water and cut earthen material into the apparatus <NUM> for processing. In some embodiments, the vacuum pump <NUM> is a positive displacement pump. Such positive displacement pumps may include dual-lobe or tri-lobe impellers (e.g., a screw rotor) that draw air into a vacuum side of the pump and forces air out the pressure side. In some embodiments, the pump is capable of generating a vacuum of at least <NUM> kPa (<NUM>" Hg) and/or a flow rate of at least about <NUM> cubic meters (<NUM> cubic feet per minute). The pump may be powered by a motor having a power output of, for example, at least <NUM> kW (<NUM> hp), at least <NUM> kW (<NUM> hp) or even at least <NUM> kW (<NUM> hp).

The separation vessel <NUM> and cyclones <NUM> are part of a separation system <NUM> for removing spoil material from the airstream. The separation vessel <NUM> is a first stage separation in which the bulk of spoil material is removed from the airstream with carryover material in the airstream being removed by the cyclones <NUM> in a second stage (i.e., the separation vessel <NUM> is the primary separation vessel with the downstream cyclones <NUM> being secondary separation vessels).

Spoil material containing water and cut earth is introduced into the separation vessel <NUM> through inlet conduit <NUM> (<FIG>). At least a portion of spoil material falls from the airstream to a spoil material outlet <NUM> and into an airlock <NUM>. Air removed through air outlets <NUM> is processed in cyclones <NUM> (<FIG>) to remove at least a portion of carryover spoil material.

Typically the particle size of spoils entering the cyclones <NUM> will be smaller than spoil particles removed by the separation vessel <NUM>. Spoils removed from the air by the cyclones <NUM> are typically fluidic. Spoil material removed by the cyclones <NUM> is fed by the cyclone discharge pump <NUM> (<FIG>) to the dewatering system <NUM> described further below (e.g., directly to a vibratory screen). Air exiting the cyclones <NUM> passes through a filter element before entering the vacuum pump <NUM> (<FIG>). The air is pulled through the vacuum pump <NUM> and exits the apparatus through the air exhaust <NUM>.

The separation vessel <NUM> has an inlet <NUM> (<FIG>) and a spoil material outlet <NUM> disposed below the inlet <NUM>. An air outlet <NUM> (<FIG>) is disposed above the inlet <NUM>. In the illustrated embodiment, the separation vessel <NUM> includes a plurality of air outlets <NUM>. In other embodiments, the separation vessel <NUM> may include a single air outlet <NUM>. The outlets <NUM> are fluidly connected to the cyclones <NUM> (<FIG>) to separate material that remains entrained in the airstream withdrawn from the outlets <NUM>.

The cyclones <NUM> may be part of a cyclonic separation system <NUM> (<FIG>). As shown in <FIG>, the cyclonic separation system <NUM> includes the cyclones <NUM> and the cyclone discharge pump <NUM>. In the embodiment illustrated in <FIG>, the cyclone discharge pump is a peristaltic pump that is connected to the cyclone discharge <NUM> by conduits (e.g., hoses or ducts). An example peristaltic pump <NUM> is shown in <FIG> described further below.

Another embodiment of the cyclonic separation system <NUM> is shown in <FIG>. The cyclones <NUM> receive airflow from the separation vessel outlets <NUM> (<FIG>) through cyclone inlets <NUM> (<FIG>). Cyclonic action in the cyclones <NUM> causes entrained material to fall to the cyclone solids outlet <NUM> (<FIG>). It should be noted that "solids outlet" should not be considered in a limiting sense and any type of material may fall through the solids outlet <NUM> (e.g., water, mud, sand, sticks, etc.). Air is pulled through the cyclones <NUM> and is discharged through cyclone discharge manifolds 78A, 78B and is directed to one or more filter elements before entering the vacuum pump <NUM> (<FIG>).

The cyclone solids outlets <NUM> should be sized to reduce or prevent bridging of granular material that passes through the outlets <NUM>. The cyclone solids outlets <NUM> are fluidly connected to conveyors 80A, 80B (e.g., the outlets <NUM> are formed in the conveyor housing <NUM>). The conveyors 80A, 80B are sealed to reduce or prevent air from entering the vacuum system through the conveyors 80A, 80B (e.g., having gaskets or bearings or the like that seal the conveyor from the ambient atmosphere). In the illustrated embodiment, the conveyors 80A, 80B are screw conveyors (e.g., an auger) having a rotating screw 82A, 82B (<FIG>). As shown in <FIG>, the screw conveyor may be a centerless screw conveyor (i.e., lacking a center shaft). In other embodiments, the screw conveyor may include a center shaft. In yet other embodiments, the one or more conveyors <NUM> may be slat conveyors, belt conveyors or rotary vane conveyors.

The conveyors <NUM> are powered by motors 80A, 80B which may be quick-attach motors to facilitate clean-out of the conveyors <NUM>. The conveyors <NUM> include access clamps <NUM> (<FIG>) that may be opened to allow the motors <NUM> and screw <NUM> to be removed the conveyor housing <NUM> (<FIG>) as shown in <FIG>. The conveyor screw <NUM> may be connected to the motor <NUM> to allow both the motor and screw to be removed from the conveyor housing as a single piece.

The longitudinal axis A<NUM> (<FIG>) of the conveyors 80A, 80B is generally orthogonal to the longitudinal axis A<NUM> of the cyclones <NUM>. The conveyors <NUM> may be sized and shaped to allow the conveyor to accept surges of material relatively quickly to reduce or prevent bridging of material through cyclone outlets <NUM>. As shown in <FIG>, the conveyor screw <NUM> may be off-center with the center of the screw <NUM> being closer to the bottom of the housing <NUM> (<FIG>) (i.e., the screw <NUM> is undersized compared to the housing <NUM>).

The cyclonic separation system <NUM> may generally include any number of cyclones <NUM> and conveyors <NUM> (e.g., one conveyor, two conveyors or more and/or at least one cyclone, at least two, at least three, at least four, at least five, at least six or more cyclones <NUM>). The cyclonic separation system <NUM> generally does not include an airlock unless stated otherwise.

The conveyors <NUM> convey material toward conveyor outlets 84A, 84B (<FIG>) where the material is discharged into the cyclone discharge pump <NUM>. In some embodiments, the cyclone discharge pump <NUM> is a peristaltic pump. The peristaltic pump <NUM> seals the system <NUM> by reducing the amount of air that may enter the system <NUM>. Referring now to <FIG>, such peristaltic pumps may include a plurality of rollers <NUM> that rotate about the pump. The rollers <NUM> compress a hose or tube <NUM> in succession as they rotate to push material through a pump outlet <NUM>. In the illustrated embodiment, the pump <NUM> includes four rollers <NUM>. In other embodiments, more or less than four rollers <NUM> may be used. The rollers <NUM> may be configured to retract as shown in <FIG> (e.g., as when the pump <NUM> is not in operation). Configuring the rollers <NUM> to retract while not in operation allows the pump <NUM> to receive material that is discharged from the cyclones <NUM> during storage and transportation. Retraction of the rollers <NUM> also assists in winterization, cleaning, and replacement of the tube <NUM> and may extend the life of the tube <NUM>.

The rollers <NUM> may pivot about a pivot pin <NUM> to retract with a biasing element <NUM> (e.g., spring) biasing the rollers in an extended position. Retraction of the rollers <NUM> may be automated by configuring the pump to reverse to cause the rollers <NUM> to retract when the pump <NUM> is switched off.

In the embodiment of <FIG>, material may fall by gravity through the pump inlet <NUM> and into the hose <NUM>. Material discharged from the pump <NUM> is conveyed to the dewatering system <NUM> (<FIG>) through outlet <NUM>.

The cyclonic separation system <NUM> may be part of the hydro excavation vacuum apparatus <NUM> as shown in <FIG> or may be used in other applications such as in reclaimers (e.g., drill fluid reclaimers).

The separation vessel <NUM> includes an upper portion <NUM> (<FIG>) having a sidewall <NUM> and one or more air outlets <NUM> formed in the sidewall <NUM>. The vessel <NUM> includes a lower portion <NUM> that tapers to the spoil material outlet <NUM> (<FIG>). The upper portion <NUM> and lower portion <NUM> may be adapted (e.g., shaped), at least in part to ease manufacturing, for fit-up and for minimizing the potential for creating internal surface features where material could set and build-up in the inner surfaces of the separation vessel <NUM>.

In the illustrated embodiment, the lower portion <NUM> is conical. The conical lower portion <NUM> may be arranged (e.g., with a sufficient slope) to reduce potential for cut earthen material to collect on the lower portion <NUM>. The illustrated lower portion <NUM> of the separation vessel <NUM> has a circular, cross-section to eliminate internal corners where cuttings may set and build-up. In other embodiments, the lower portion <NUM> may have a non-circular cross-sectional profile. For example, the lower portion <NUM> may include a generally square profile with relatively large fillets at each corner. In the illustrated embodiment, the upper portion <NUM> has a circular or generally circular cross-section. The upper portion <NUM> may be cylindrical to ease the transitioning to the conical lower portion <NUM>.

The inlet <NUM> extends through the conical lower portion <NUM>. In other embodiments, the inlet extends through the upper portion <NUM>. The vessel <NUM> has a central vertical axis D (<FIG>).

The separation vessel <NUM> may be sized to reduce the dwell time of material in the vessel. The dwell time (DT) may be determined from the following formula: <MAT> where Vol is the open volume of the vessel (i.e., volume not taken up by spoil material) and Q is the volumetric rate (e.g., actual CFM) at which air is pulled by the vacuum system <NUM>. In some embodiments, the dwell time may be less than <NUM> seconds, less than <NUM> seconds or less than <NUM> second (at standard cubic feet). Dwell time.

In some embodiments, the apparatus <NUM> includes a single separation vessel <NUM> in the first stage removal of solids and water from the airstream. In other embodiments, two or more separation vessels <NUM> are operated in parallel in the first stage removal of solids and water from the airstream. In some embodiments, the separation vessel <NUM> processes from <NUM><NUM> (<NUM> ft<NUM>) of spoil material per minute to <NUM><NUM> (<NUM> ft<NUM>) of spoil material per minute.

In the illustrated embodiment, the separation vessel <NUM> is a deceleration vessel in which the velocity of the airstream is reduced causing material to fall from the airstream toward a bottom of the separation vessel <NUM>. The deceleration vessel <NUM> may be part of a deceleration system <NUM> (<FIG>) for removing material from the airstream by gravity.

The deceleration vessel <NUM> is adapted to allow material to fall from the airstream by gravity rather than by vortexing of air within the vessel <NUM>. In some embodiments, the inlet <NUM> of the vessel <NUM> is arranged such that the airstream does not enter the vessel <NUM> tangentially. For example, as shown in <FIG> and <FIG>, the inlet conduit <NUM> (and inlet <NUM>) may have a longitudinal axis E that passes through the central vertical axis D of the deceleration vessel <NUM>. In other embodiments, the longitudinal axis E is separated a relatively small amount from the central vertical axis D of the deceleration vessel <NUM> (e.g., by a distance less than <NUM>% of the radius of vessel <NUM> or a distance less than <NUM>%, <NUM>%, <NUM>% or <NUM>% of the radius of the vessel <NUM>).

To allow material to fall from the airstream, the deceleration vessel <NUM> may have an effective cross-sectional area (i.e., cross-sectional area of void space) larger than the cross-sectional area of the inlet conduit <NUM> to reduce the velocity of the airstream in the vessel <NUM>. For example, the ratio of the effective cross-sectional area of the deceleration vessel <NUM> to the effective cross-sectional area of the inlet conduit <NUM> may be at least about <NUM>:<NUM> or, as in other embodiments, at least about <NUM>:<NUM>, at least about <NUM>:<NUM> or even at least about <NUM>:<NUM> to reduce the velocity of the airstream to allow material to fall from the airstream.

In the illustrated embodiment in which the deceleration vessel <NUM> and inlet conduit <NUM> are circular, the effective cross-sectional area of the deceleration vessel <NUM> is proportional to the squared radius of the upper portion <NUM> of the deceleration vessel <NUM> and the effective cross-sectional area of the inlet conduit <NUM> is proportional to the squared radius of the inlet conduit <NUM>. In some embodiments, the ratio of the radius of the deceleration vessel <NUM> to the radius of the inlet conduit may be at least about <NUM>:<NUM>, at least about <NUM>:<NUM>, or even at least about <NUM>:<NUM>.

The deceleration system <NUM> also includes a deflection plate <NUM> disposed within the deceleration vessel <NUM>. The deflection plate <NUM> is configured and positioned to cause spoil material entrained in the airstream to contact the plate <NUM> and be directed downward toward the spoil material outlet <NUM>. The deflection plate <NUM> includes a material-engaging face <NUM> (<FIG>) configured to contact material entrained in the airstream. The face <NUM> has a longitudinal plane F and the plane F forms an angle λ with the vertical axis D of the vessel <NUM>. In some embodiments, the angle λ between the longitudinal plane F of the material-engaging face <NUM> of the deflection plate <NUM> and the vertical axis D of the vessel <NUM> may be from about <NUM>° to about <NUM>° or from about <NUM>° to about <NUM>°.

As shown in <FIG>, the longitudinal axis E of the inlet conduit <NUM> (and inlet <NUM>) may intersect the deflection plate <NUM>. Alternatively or in addition, the central vertical axis D may intersect the deflection plate <NUM> or the plate may be forward or rearward to the central vertical axis D (e.g., forward or rearward up to <NUM>% of the radius or forward or rearward up to <NUM>%, <NUM>% or <NUM>% of the radius of the vessel).

In some embodiments and as shown in <FIG>, the deflection plate <NUM> includes a wear plate <NUM> connected to a support <NUM> to allow the wear plate <NUM> to be replaced upon the plate <NUM> becoming worn. The wear plate <NUM> may be made of an abrasion resistant material including steel (e.g., AR400 abrasion resistant steel) or abrasion resistant plastics.

In other embodiments, a separation vessel <NUM> using cyclonic separation (i.e., a cyclone) in which airflow travels in a helical pattern is used to remove material from the airstream.

An example airlock <NUM> is shown in <FIG> and <FIG>. The airlock <NUM> includes a plurality of rotatable vanes <NUM> connected to a shaft <NUM>. The vanes <NUM> rotate along a conveyance path in the direction shown by arrow R in <FIG>. The shaft <NUM> is connected to a motor <NUM> (<FIG>) that rotates the shaft <NUM> and vanes <NUM>. The airlock <NUM> has an airlock inlet <NUM> through which material passes from the deceleration vessel <NUM> and an airlock outlet <NUM> through which water and cut earthen material are discharged.

The airlock <NUM> includes a housing <NUM> (<FIG>) with the vanes <NUM> rotating within the housing <NUM>. The housing <NUM> includes a first sidewall <NUM>, a second sidewall <NUM>, and an outer annular wall <NUM> that extends between the first sidewall <NUM> and the second sidewall <NUM>.

The vanes <NUM> include a main portion <NUM> and an outer wear strip <NUM> that is connected to the main portion <NUM> by fasteners <NUM>. The outer wear strip <NUM> extends toward the outer annular wall <NUM> of the housing <NUM>. During rotation, there may be a small gap between the wear strip <NUM> and the outer annular wall <NUM> of the housing <NUM>. Material may lodge between the wear strip <NUM> and the annular wall <NUM> causing the wear strip to wear. As the strip <NUM> wears, it may be adjusted outward (e.g., by use of slots in the strip <NUM> through which the fasteners <NUM> extend). Alternatively, the strip <NUM> may be replaced when it is worn out or no longer functional.

Air may pass from the ambient environment, through the gaps between the vanes <NUM> or wear strips <NUM> and the outer annular wall <NUM> and into the vacuum system <NUM> (<FIG>). In other embodiments, the vanes <NUM> contact the outer annular wall <NUM> (e.g., as with wiper vanes) to more fully seal air from the vacuum system <NUM>.

As shown in <FIG>, the airlock outlet <NUM> has a vertex <NUM>. Proceeding in the direction of rotation of the vanes <NUM>, the airlock outlet <NUM> tapers outwardly from the vertex <NUM> toward at least one sidewall <NUM>, <NUM>. In the illustrated embodiment, the outlet <NUM> tapers from the vertex <NUM> toward the first sidewall <NUM> and tapers from the vertex <NUM> toward the second sidewall <NUM> (i.e., proceeding in the direction of rotation of the vanes, the first portion of the outlet <NUM> is triangular in shape). The outlet <NUM> may taper toward the sidewalls <NUM>, <NUM> in a straight path as shown or, as in other embodiments, in a curved path.

As shown in <FIG>, the outer annular wall <NUM> has a center plane H that is midway between the first and second sidewalls <NUM>, <NUM>. In the illustrated embodiment, the vertex <NUM> is at the center plane H.

Alternatively or in addition, the vanes <NUM> may taper to allow a small opening to be exposed to the ambient as the vanes rotate.

Two adjacent vanes <NUM> collectively form a pocket <NUM> (<FIG>) which receives spoil material. The airlock <NUM> may also include pocket sidewalls <NUM> (<FIG>) that contact and rotate with the vanes <NUM>. In other embodiments, the airlock <NUM> does not include pocket sidewalls <NUM>.

In some embodiments, the airlock has less than about <NUM> vanes, less than about <NUM> vanes or about <NUM> vanes or less. In some embodiments, the vanes <NUM> rotate at a speed of less than about <NUM> RPM or less than about <NUM> RPM or even less than about <NUM> RPM.

The number of vanes <NUM> and the diameter of the airlock <NUM> are selected in some embodiments so that the pocket <NUM> may accommodate the largest size of cut earthen material that may travel through the vacuum system <NUM> to the separation vessel <NUM>. Generally, the largest material that could reach the airlock is material with a diameter equal to the diameter D1 of the conduits through which air and cut earthen material travel to the separation vessel <NUM>. In some embodiments, the vanes <NUM> are sized to receive particles P with a diameter D1 (<FIG>) or greater. For example, in some embodiments, the vane pockets <NUM> may have a depth d of D1 or more. Alternatively or in addition, the pocket <NUM> may have width w of D1 or more at a mid-point MP of the pocket, the mid-point MP being midway between a top <NUM> and bottom <NUM> of the pocket <NUM>.

Water and cut earth that exits the airlock <NUM> through the airlock outlet <NUM> (<FIG>) is introduced into the dewatering system <NUM> described further below (e.g., may be gravity fed to the dewatering system <NUM> as shown in the illustrated embodiments). In some embodiments, the water and cut earthen material is directly introduced into the dewatering system <NUM> (e.g., directly fed to a screening system without intermediate processing).

The dewatering system <NUM> (<FIG>) of some embodiments includes a pre-screen <NUM> that first engages material discharged from the outlet <NUM> of the airlock <NUM>. In the illustrated embodiment, the pre-screen <NUM> has a plurality of slats <NUM> with openings formed between slats <NUM> through which material falls. The pre-screen <NUM> may have relatively large openings (e.g., at least about <NUM> (<NUM> inches), at least about <NUM> (<NUM> inch), at least about <NUM> (<NUM> inches), or <NUM> (<NUM> inches) or more) such that relatively large material is prevented from passing through the pre-screen <NUM>. The slats <NUM> have ribs <NUM> which reinforce the slats <NUM>.

The pre-screen <NUM> may be adapted to withstand the impact of large stones and earthen material that are capable of being removed by the vacuum system <NUM> (<FIG>). Example screens include screens that may be referred to by those of skill in the art as a "grizzly screener" or simply "grizzly. " The pre-screen <NUM> may vibrate or, as in other embodiments, does not vibrate.

The dewatering system <NUM> of this embodiment includes a vibratory screen <NUM>, more commonly referred to as a "shaker", that separates material that passes through the pre-screen <NUM> by size. The vibratory screen <NUM> has openings with a size smaller than the size of the openings of the pre-screen <NUM>. In some embodiments, the size of the openings of the vibratory screen <NUM> are less than <NUM> micron, less than about <NUM> micron or less than about <NUM> micron. The ratio of the size of the openings of the pre-screen <NUM> to the size of the openings of the vibratory screen <NUM> may be at least about <NUM>:<NUM>, at least about <NUM>:<NUM>, or even at least about <NUM>:<NUM>. The listed size of the openings and ratios thereof are exemplary and other ranges may be used unless stated otherwise.

The vibratory screen <NUM> may be part of a shaker assembly <NUM>. The shaker assembly <NUM> includes vibratory motors <NUM> that cause the screen <NUM> to vibrate. The shaker assembly <NUM> may be configured to move the vibratory screen <NUM> linearly or in an elliptical path (e.g., by arranging the number of motors, orientation of the motors, and/or placement of the motors to move the vibratory screen <NUM> linearly or in an elliptical path).

The shaker assembly <NUM> rests on isolators <NUM> (shown as air bags) to isolate the vibratory movement of the assembly <NUM> from the chassis or frame to which it is connected. In some embodiments, the screen <NUM> is divided into multiple segments that can separately be changed out for maintenance.

As the screen <NUM> vibrates, effluent falls through openings within the screen <NUM> and particles that do not fit through the openings vibrate to the discharge end <NUM> of the assembly <NUM>. Solids that reach the discharge end <NUM> fall into a hopper <NUM> (<FIG>) and may be conveyed from the hopper <NUM> by a conveyor assembly <NUM> to form a stack of solids. Solids may be loaded into a bin, dumpster, loader bucket, ground pile, roll-off bin, dump truck or the like or may be conveyed to the site of the excavation as backfill. Solids may be transported off of the apparatus <NUM> by other methods.

In some embodiments, the apparatus <NUM> does not include a mixer for mixing spoil material (e.g., for mixing solids to promote drying or for mixing in drying agents).

Liquid that passes through the vibratory screen <NUM> collects in a catchpan <NUM> (<FIG>) and is conveyed by a return water pump <NUM> to the fluid storage and supply system <NUM> described more fully below.

Another example dewatering system <NUM> is shown in <FIG>. The dewatering system <NUM> includes a flat wire belt conveyor <NUM>. Such flat wire belt conveyors <NUM> may include spaced wires or rods which form an open mesh in the belt that allow for liquids and particles that fit through the mesh openings to pass through the mesh. The flat wire belt conveyor <NUM> may remove larger solids and unhydrated soil clumps which helps prevent downstream separation units from blinding (e.g., pluggage of mesh openings) and abrasive wear and damage. In various embodiments, the mesh size of the belt may be from about <NUM> to about <NUM> or from about <NUM> to about <NUM>.

The flat wire belt conveyor <NUM> angles upward toward the rear <NUM> (<FIG>) of the apparatus <NUM> to promote separation of water from the cut earthen material. Liquid and small solids that pass through the mesh belt <NUM> (<FIG>) fall through the top course 137A of the belt, land on the bottom course 137B of mesh (i.e., the return) and fall through the bottom course of mesh onto a conveyor floor or "chute" <NUM>. The belt <NUM> may rest on the conveyor floor <NUM> and scrape material toward the liquid discharge end of the flat wire belt conveyor <NUM>. Solids that do not pass through the openings are carried forward by the belt <NUM>. While the belt <NUM> is shown of solid, unperforated material in the Figures for simplicity, it should be understood that, in this embodiment, the belt <NUM> includes mesh openings throughout the top course 137A and bottom course 137B. The flat wire belt conveyor <NUM> may include a series of deflectors <NUM> that act to turn or otherwise redirect solids that are moving forward on the conveyor <NUM>. By turning the solids, additional fluid may fall through the conveyor <NUM> and be recovered as effluent.

The effluent that passes through the flat wire belt conveyor <NUM> is conveyed down the conveyor floor <NUM> and falls onto a shaker assembly <NUM> (<FIG>) having a vibratory screen <NUM>. The shaker assembly <NUM> may be configured similar to shaker assembly <NUM> described above and description herein of the shaker assembly <NUM> should be considered to apply to shaker assembly <NUM> unless stated otherwise. The shaker assembly <NUM> includes one or more vibratory screens <NUM> through which liquid and fine solids pass. The shaker assembly <NUM> includes a first side 159A which processes material that passes through and the flat wire belt conveyor <NUM> and a second side 159B which processes material separated by cyclones <NUM> (<FIG>). The openings of the flat wire belt conveyor <NUM> are generally larger than the openings of the shaker assembly <NUM> such that the second shaker assembly <NUM> separates finer solids.

The dewatering system <NUM> of the present disclosure may include additional separation and/or purification steps for processing cut earthen material. In some embodiments, the cut earth is separated from water only by use of a (<NUM>) a first stage pre-screen or flat wire belt conveyor, and (<NUM>) a second stage vibratory screen. In these or in other embodiments, the screen (e.g., pre-screen <NUM> or flat wire belt conveyor <NUM>) may receive spoil material directly from the separation vessel <NUM> without intermediate processing, i.e., without feeding the material to a hydrocyclone such as a desilter cone to separate water from earthen material. In some embodiments, water that passed through the screens may be fed directly to the water supply and storage system <NUM> (<FIG>) described further below without being further processed (e.g., centrifugation). In some embodiments, the water recovered from the excavation site is not treated without additives (e.g., flocculants and/or coagulants).

The hydro excavation vacuum apparatus <NUM> may include an adjustment system <NUM> (<FIG>) for adjusting a pitch and a roll of one or more screens of the dewatering system <NUM>. The adjustment system <NUM> may generally be used to adjust any screen such as the pre-screen <NUM>, vibratory screen <NUM> or flat wire belt conveyor <NUM> (<FIG>) or to adjust combinations of these screens.

The adjustment system <NUM> includes a pivot member <NUM> for adjusting the pitch and the roll of the screen. The screens pivot about a pitch axis P (<FIG>) and also pivot about a roll axis R. The pivot member <NUM> is pivotally connected to a bracket <NUM> (<FIG>) which is connected to the chassis <NUM> of the apparatus <NUM>. In the illustrated embodiment, a single pivot member <NUM> is shown. In other embodiments, two separate pivot members <NUM> are used.

Referring now to <FIG>, the pivot member <NUM> includes a first portion <NUM> to adjust the roll of the screen and a second portion <NUM> that extends from the first portion <NUM> to adjust the pitch of the screen. The first portion <NUM> of the pivot member <NUM> is perpendicular to the second portion <NUM>.

The pivot member <NUM> includes sleeves, bearings and/or bushings to allow the screen to pivot with respect to the remainder of the apparatus. In the illustrated embodiment, the first portion <NUM> contains a first portion sleeve <NUM> and a first shaft <NUM> that extends through the sleeve <NUM>. The first portion sleeve <NUM> is attached to a frame <NUM> (<FIG>) that supports the screens to allow the frame <NUM> and screens to pivot about the shaft <NUM> to adjust the roll of the screens. The second portion <NUM> includes a second portion sleeve <NUM>. The first shaft <NUM> is attached to the second portion sleeve <NUM>. A second shaft <NUM> extends through the second portion sleeve <NUM> and is connected to the bracket <NUM> (<FIG>). The second sleeve <NUM> and the screens pivot about the shaft <NUM> to adjust the pitch of the screens. In other embodiments, each of the first and second portions <NUM>, <NUM> may include a bushing or bearing such as a ball bearing or roller bearing.

The adjustment system <NUM> includes a first actuator 154A (<FIG>) and a second actuator 154B (shown as hydraulic cylinders) which work in cooperation with the pivot member <NUM> to adjust the pitch and roll of the vibratory screen <NUM>. A sensor <NUM> (<FIG>) senses the pitch and/or roll of the screen. In other embodiments, two separate sensors detect the pitch and roll, respectively. The sensor <NUM> produces a signal that is transmitted to a controller <NUM>. The controller <NUM> may be the same controller <NUM> described below for controlling the flow of liquids in the fluid storage and supply system <NUM> (<FIG>) or may be a separate controller <NUM> that includes similar components (e.g., contains processors, memory and the like as described below).

The controller <NUM> controls the actuators 154A, 154B based on input from the sensor <NUM>. Generally, the controller <NUM> controls the actuators 154A, 154B to eliminate roll within the screen (i.e., the screen is laterally level). The controller <NUM> may control the actuators 154A, 154B to achieve a target pitch of the screen <NUM>. For example, the screen <NUM> may be adjusted to have a positive pitch, negative pitch or to be level. The operator may select a pitch by a user interface (not shown) that is communicatively coupled to the controller <NUM>.

Referring now to <FIG>, in some embodiments, the pivot member <NUM> is aligned with the outlet <NUM> of the airlock <NUM> relative to the lateral axis B (<FIG>) of the apparatus <NUM>. The airlock outlet <NUM> has a width W and the pivot member <NUM> is laterally aligned with the width W of the outlet <NUM>.

Alternatively or in addition, the pivot member <NUM> may be located relatively near the airlock <NUM> relative to the longitudinal axis A (<FIG>) such that the screen upon which material is loaded from the airlock <NUM> pivots a relatively small amount near the airlock <NUM> which allows the vertical profile of the apparatus to be reduced. Referring now to <FIG> in which a flat wire belt conveyor <NUM> is shown, the conveyor <NUM> has a rear <NUM> toward which material is loaded onto the belt from the airlock outlet <NUM> and a front <NUM> toward which material is discharged from the screen. A center plane E is midway between the rear <NUM> and the front <NUM>. The pivot member <NUM> is rearward to the center plane E of the screen <NUM> relative to the longitudinal axis A (<FIG>) (i.e., the pivot member <NUM> is nearer the rear <NUM> than the front <NUM> of the screen).

The airlock <NUM> has a bottom <NUM>. The bottom <NUM> of the airlock <NUM> and the rear <NUM> of the screen are separated by a distance D1 relative to the longitudinal axis A (<FIG>). The bottom <NUM> of the airlock <NUM> and the front <NUM> of the screen <NUM> are separated by a distance D2 relative to the longitudinal axis A. The distance D1 between the bottom <NUM> of the airlock <NUM> and the rear <NUM> of the screen <NUM> is less than the distance D2 between the bottom <NUM> of the airlock <NUM> and the front <NUM> of the screen <NUM>.

The pivot member <NUM> of the illustrated embodiment allows two degrees of freedom (e.g., roll and pitch) in which to adjust the screen. In some embodiments, the apparatus <NUM> does not include a panhard rod to eliminate a third degree of freedom (e.g., yaw).

The hydro excavation vacuum apparatus <NUM> includes a fluid storage and supply system <NUM> (<FIG>) which supplies water for high pressure excavation and stores water recovered from the dewatering system <NUM>. The fluid storage and supply system <NUM> includes a plurality of vessels <NUM> for holding fluid. In the illustrated embodiment, the vessels <NUM> are sections of a baffled tank <NUM> (<FIG>) with the vessels <NUM> being separated by baffles <NUM>. The tank baffles <NUM> generally extend from the bottom <NUM> to the top <NUM> of each vessel <NUM> such that fluid does not pass over the baffles <NUM> into adjacent vessels. In other embodiments, the vessels <NUM> are separate tanks. In some embodiments, water is not processed when transferred between tanks (e.g., further purification such as by centrifugation in hydrocyclones or by addition of additives such as flocculants or coagulants).

In the embodiment illustrated in <FIG>, the fluid storage and supply system <NUM> includes four vessels <NUM>. In other embodiments, the system <NUM> may include two vessels <NUM> (<FIG>), three vessels <NUM> (<FIG>) or more than four vessels <NUM> (e.g., five, six or more vessels).

The fluid storage and supply system <NUM> carries fluid used for high pressure excavation. As excavation of a site begins, the hydro excavation vacuum apparatus <NUM> processes earth cuttings and reclaimed water from the excavation site with reclaimed water being stored in the fluid storage and supply system <NUM>. The initial water used for excavation (i.e., water not having been processed through the dewatering system <NUM> of the apparatus <NUM>) may be referred herein as "maiden water. " Water that has been reclaimed from the excavation site and stored in the fluid storage and supply system <NUM> may be referred to herein as "first cycle water. " In some embodiments, first cycle water may be used as the source of water for high pressure excavation. In such embodiments, the reclaimed water may be referred to as "second cycle water. " Additional cycles may be performed to produce "third cycle water," "fourth cycle water," and so on. The fluid storage and supply system <NUM> is adapted to allow maiden water to remain separated from first cycle water without having dedicated empty tank space to reduce the volume of tanks carried on the apparatus <NUM>.

Referring now to <FIG>, the fluid storage and supply system <NUM> includes a first vessel 30A. The first vessel 30A is in fluid communication with the excavation fluid pump <NUM> (<FIG>). The system <NUM> may include a first vessel pump 38A that may provide head pressure for the excavation fluid pump <NUM> or that may be used to empty out the first vessel 30A. In other embodiments, the first vessel pump 38A is eliminated. The fluid storage and supply system <NUM> also includes a second vessel 30B that is in fluid communication with the dewatering system <NUM> to receive first cycle water discharged from the dewatering system <NUM>. A return water pump <NUM> (<FIG>) conveys first cycle water from the catchpan <NUM> of the dewatering system <NUM> to the second vessel 30B. The return water pump <NUM> may operate upon activation of a float or may run continually to move first cycle water to the second vessel 30B.

A first vessel level sensor 36A measures the level of fluid in the first vessel 30A and a second vessel level sensor 36B measures the level of fluid in the second vessel 30B. A second vessel transfer pump 38B pumps fluid from the second vessel 30B (e.g., to the first vessel 30A as in two vessel embodiments or to a third vessel as in embodiments having three or more vessels).

As shown in <FIG>, in some embodiments, the system <NUM> includes a third vessel 30C or even a fourth vessel 30D. The third vessel 30C is in fluid communication with the second vessel 30B. The second vessel transfer pump 38B transfers fluid from the second vessel 30B into the third vessel 30C. A third vessel transfer pump 38C transfers fluid to the first vessel 30A or, in embodiments in which the system <NUM> includes a fourth vessel, to the fourth vessel 30D. A third vessel level sensor 36C senses the fluid level in the third vessel 30C.

In embodiments in which the fluid storage and supply system <NUM> includes a fourth vessel 30D, the fourth vessel 30D is in fluid communication with the third vessel 30C. A fourth vessel level sensor 36D senses the fluid level in the fourth vessel 30D. A fourth vessel transfer pump 38D transfers fluid from the fourth vessel 30D to the first vessel 30A.

The level sensors 36A, 36B, 36C, 36D may be ultrasonic sensors, radar sensors, capacitance sensors, float sensors, laser sensors or the like.

The vessels <NUM> of the fluid storage and supply system <NUM> may be separate compartments of a single tank as shown in <FIG> or may be separate tanks or may be a combination of compartmentalized tanks and separate tanks.

Cycling of water within the fluid storage and supply system <NUM> is illustrated in <FIG>. While cycling of water in the system <NUM> may be described and shown with reference to four vessels <NUM>, the description is also applicable to two or three vessel systems unless stated differently.

To perform an excavation, the first vessel 30A and, if equipped and as in the embodiment of <FIG>, the third vessel 30C, and fourth vessel 30D, are filled with maiden water <NUM>, indicated by stippling. The source of maiden water may be potable water, surface water (e.g., pond, river, ditch water) or grey water substantially fee of abrasive grit. After filling, the maiden water <NUM> in the first vessel 30A has an initial level. The hydro vacuum excavating apparatus <NUM> is then transported from the site at which the vessels are filed with maiden water to a second site at which a high-pressure water excavation is performed. During excavation of a site, the excavation fluid pump <NUM> (<FIG>) directs high-pressure maiden water through the wand <NUM> (<FIG>). During excavation, the vacuum system <NUM> (<FIG>) causes spoil material to become entrained in an airstream and pass through the boom <NUM> and other conduits and into the separation vessel <NUM>. Spoil material is separated from the airstream by the separation vessel <NUM> and cyclones <NUM>. The spoil material is introduced into the dewatering system <NUM> through airlock <NUM> and/or pumped from the cyclone discharge pump <NUM>. The first cycle water is separated from spoil material in the dewatering system <NUM>. The separated first cycle water is directed to the second vessel 30B. Solids discharged from the dewatering system <NUM> falls into a hopper <NUM> (<FIG>) and are conveyed from the hopper <NUM> by a conveyor assembly <NUM> to form a stack of solids.

As excavation commences, maiden water <NUM> is drawn from the first vessel 30A causing the level of fluid in the first vessel 30A to be reduced below the initial level (<FIG>). The first vessel level sensor 36A senses the reduction in the fluid level in the first vessel 30A. Once the level of maiden water in the first vessel 30A is reduced to below the initial level or is even reduced further (e.g., reduced to a level of about <NUM>% of the initial level or less, about <NUM>% or less, about <NUM>% or less, about <NUM>% or less, about <NUM>% or less, about <NUM>% less or when the first vessel 30A is emptied of maiden water <NUM>), additional maiden water <NUM> is transferred to the first vessel 30A. For example, maiden water may be pumped from the fourth vessel 30D into the first vessel 30A to maintain a level of fluid in the first vessel 30A for excavation. In embodiments in which the system <NUM> includes three vessels (<FIG>), maiden water may be pumped from the third vessel 30C into the first vessel 30A.

In this manner, additional maiden water may be directed toward the excavation site after the volume of the maiden water used for excavation is at least the volume of the first vessel 30A (i.e., additional excavation may be performed after the volume of maiden water in the first vessel 30A is consumed). Water may be transferred within the system <NUM> as excavation is being performed and the dewatering system <NUM> operates.

As maiden water <NUM> is transferred from the fourth vessel 30D into the first vessel 30A, the level of fluid in the fourth vessel 30D is reduced. As the level of fluid in the fourth vessel 30D is reduced to below the initial level or less (e.g., to a level of about <NUM>% of the initial level or less, or about <NUM>% or less, about <NUM>% or less, about <NUM>% or less, about <NUM>% or less, about <NUM>% less or when the fourth vessel is emptied of maiden water), maiden water from the third vessel 30C is transferred to the fourth vessel 30D (<FIG>).

During excavation, the empty second vessel 30B begins to fill with first cycle water <NUM>, shown with heavier stippling in <FIG>. The second vessel 30B continues to fill with first cycle water <NUM> (<FIG>) as excavation continues. After the third vessel 30C is emptied of maiden water (<FIG>), first cycle water <NUM> is transferred from the second vessel 30B into the third vessel 30C (<FIG>). Once the fourth vessel 30D is emptied of maiden water <NUM>, first cycle water <NUM> from the third vessel 30C may be pumped to the fourth vessel 30D (<FIG>).

After the maiden water in the fluid storage and supply system <NUM> is consumed, first cycle water may be used for excavation. The first cycle water <NUM> may be transferred into the first vessel 30A (<FIG>). The excavation fluid pump <NUM> (<FIG>) directs pressurized first cycle water <NUM> from the first vessel 30A toward an excavation site to cut earthen material. The cut earth and first cycle water (now second cycle water) are removed from the excavation site. The second cycle water is separated from the cut earthen material in the dewatering system <NUM> (<FIG>) with the second cycle water being introduced into the second vessel 30B. As excavation continues, the second cycle water is subsequently introduced into the third vessel 30C, fourth vessel 30D, and/or first vessel 30A. After first cycle water is consumed, the second cycle water may be used for excavation by transferring second cycle water into the first vessel 30A. The excavation fluid pump <NUM> directs pressurized second cycle water from the first vessel 30A toward an excavation site. Additional cycles may be performed to reuse reclaimed water and reduce the frequency at which maiden water is loaded onto the apparatus.

In some embodiments, the fluid processed through the dewatering system <NUM> (e.g., first cycle water, second cycle water, etc.) and stored in the fluid storage and supply system <NUM> is monitored to determine if the fluid is suitable for use for excavation. The fluid may be monitored manually or automatically. The fluid may be monitored by measuring clarity, translucence, conductivity, viscosity, specific gravity, or the like. Fluid that is unsuitable for excavation may be disposed (e.g., municipal water treatment) or may be treated in a separate reclamation system (e.g., with coagulant or flocculant treatment). An example reclamation system is disclosed in <CIT>, entitled "Systems and Methods for Dosing Slurries to Remove Suspended Solids," which is incorporated herein by reference for all relevant and consistent purposes.

Another embodiment of the fluid storage and supply system <NUM> is shown in <FIG> and <FIG>. The system <NUM> generally includes the components of the system described above with several differences being described below. As shown in <FIG>, the drive motor <NUM> of each pump <NUM> (first motor 34A and first vessel pump 38A being shown in <FIG>) is disposed above the vessel 30A. The bottom <NUM> of each vessel <NUM> angles downward toward the pump <NUM> to allow the vessels to be more fully emptied. At least one of the vessels <NUM> such as the first vessel 30A (<FIG>) includes an airgap device <NUM> as shown in <FIG> to prevent siphoning and cross-contamination through the transfer pipes <NUM>.

Referring now to <FIG>, the system <NUM> includes a discharge manifold <NUM> for offloading water from the system <NUM> (e.g., recycled water such as first cycle water, second cycle water or the like). The system <NUM> includes valves 45A, 45B, 45C, 45D that are actuated to selectively move water within the system. During excavation and during recovery of water from the earthen slurry, the first valve 45A is positioned to direct maiden water discharged from the first vessel pump 38A to the excavation pump <NUM> (<FIG>). The second, third, and fourth valves 45B, 45C, 45D are positioned to direct water (e.g., maiden water or recycled water depending on how much maiden water and recycled water is in the system) to the next vessel in the system <NUM>. To drain any of the vessels 30A, 30B, 30C, 30D with water, the corresponding valve 45A, 45B, 45C, 45D may be positioned such that water drains into the discharge manifold <NUM>. The discharge manifold <NUM> includes an outlet through which water may exit the system <NUM>.

In some embodiments, the discharge manifold <NUM> may be used while filling the system <NUM> with maiden water. For example, maiden water is directed into the first vessel 30A (<FIG>) through airgap device <NUM>. The first pump 38A is operated and the valve 45A is positioned to direct maiden water from the first vessel 30A to the discharge manifold <NUM> (<FIG>). The outlet of the discharge manifold is closed such that the manifold <NUM> fills with water. The third and fourth vales 45C, 45D are positioned to allow maiden water to flow from the manifold <NUM>, through pumps 38C, 38D (i.e., pumps 38C, 38C are off and water is caused to back-flow through pumps 38C, 38D). In this manner the first, third and fourth vessels 30A, 30C, 30D can be filled with maiden water. The second valve 45B is positioned such that the second tank 30B is not in fluid communication with the manifold <NUM> to allow the second tank 30B to remain empty to receive first cycle water. The system <NUM> may be automated by controlling the first pump 38A to cause the first, third and fourth vessels 30A, 30C, 30D to be at or near the same level during filling (e.g., by use of level sensors 36A, 36C, 36D).

Referring now to <FIG>, each valve <NUM> includes a plunger <NUM>. In the lowered position, the plunger <NUM> directs fluid that is received from the transfer pump in transfer pump conduit <NUM> to the transfer pipe <NUM> that is in fluid communication with the next vessel in the system <NUM> or with the excavation pump <NUM> (<FIG>). In the raised position of the plunger <NUM>, fluid is directed from the transfer pump conduit <NUM> to the discharge conduit <NUM> which is connected to the discharge manifold <NUM> (<FIG>) (or flows in the reverse direction such that maiden water flows from the manifold <NUM> to the tanks 30C, 30D such as when filling the system <NUM> with maiden water). In the illustrated embodiment, the valve <NUM> is actuated by hand by lever <NUM>. In other embodiments, actuation of each valve <NUM> is automated.

In some embodiments, the fluid storage and supply system <NUM> includes a controller <NUM> (<FIG>) that enables the second vessel transfer pump 38B, third vessel transfer pump 38C, and/or the fourth vessel transfer pump 38D to operate based at least in part on an output signal from the first vessel level sensor 36A, second vessel level sensor 36B, third vessel level sensor 36C, and/or fourth vessel level sensor 36D.

The controller <NUM> is communicatively coupled to the second vessel transfer pump 38B, third vessel transfer pump 38C, and the fourth vessel transfer pump 38D. The controller <NUM> selectively powers the pumps 38B, 38C, 38D to move maiden water and first cycle water within the vessels 30A, 30B, 30C, 30D as discussed further herein. The controller <NUM> may also be communicatively or operatively coupled to the first vessel pump 38A (e.g., to operate the pump 38A when the excavation pump <NUM> is operating or to unload all fluid from the first vessel 30A).

The controller <NUM> may control the pumps 38B, 38C, 38D based on instructions stored in a memory device (not shown), input received from sensors 36A, 36B, 36C, 36D, input from a user via a user interface, and/or input received from any other suitable data source.

Controller <NUM>, the various logical blocks, modules, and circuits described herein may be implemented or performed with a general purpose computer, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Example general purpose processors include, but are not limited to only including, microprocessors, conventional processors, controllers, microcontrollers, state machines, or a combination of computing devices.

Controller <NUM> includes a processor, e.g., a central processing unit (CPU) of a computer for executing instructions. Instructions may be stored in a memory area, for example. Processor may include one or more processing units, e.g., in a multi-core configuration, for executing instructions. The instructions may be executed within a variety of different operating systems on the controller, such as UNIX, LINUX, Microsoft Windows®, etc. It should also be appreciated that upon initiation of a computer-based method, various instructions may be executed during initialization. Some operations may be required in order to perform one or more processes described herein, while other operations may be more general and/or specific to a particular programming language e.g., and without limitation, C, C#, C++, Java, or other suitable programming languages, etc..

Processor may also be operatively coupled to a storage device. Storage device is any computer-operated hardware suitable for storing and/or retrieving data. In some embodiments, storage device is integrated in controller. In other embodiments, storage device is external to controller and is similar to database. For example, controller may include one or more hard disk drives as storage device. In other embodiments, storage device is external to controller. For example, storage device may include multiple storage units such as hard disks or solid state disks in a redundant array of inexpensive disks (RAID) configuration. Storage device may include a storage area network (SAN) and/or a network attached storage (NAS) system.

In some embodiments, processor is operatively coupled to storage device via a storage interface. Storage interface is any component capable of providing processor with access to storage device. Storage interface may include, for example, an Advanced Technology Attachment (ATA) adapter, a Serial ATA (SATA) adapter, a Small Computer System Interface (SCSI) adapter, a RAID controller, a SAN adapter, a network adapter, and/or any component providing processor with access to storage device.

Memory area may include, but are not limited to, random access memory (RAM) such as dynamic RAM (DRAM) or static RAM (SRAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and non-volatile RAM (NVRAM). The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.

In some embodiments, the fluid storage and supply system <NUM> includes a valving system <NUM> (<FIG>) for switching the source of water used for high pressure excavation from vessel to vessel. The valving system <NUM> allows one of the first vessel 30A, 30B, 30C, 30D to be in fluid communication with the fluid excavation pump <NUM> and wand <NUM>. In this manner, additional maiden pressurized water may be directed toward the excavation site after the volume of the maiden pressurized water used for excavation is at least the volume of the first vessel 30A (i.e., additional excavation may be performed after the volume of maiden water in the first vessel 30A is consumed). The valving system <NUM> may include hand-operated valves for switching the source of water used for excavation or the system <NUM> may include a controller (not shown) which controls the valving system <NUM> based on, at least in part, a signal from at least one of the first vessel level sensor 36A, the second vessel level sensor 36B, the third vessel level sensor 36C, and the fourth vessel level sensor 36D.

Alternatively or in addition, a valving system (not shown) may be used to select which vessel 30A, 30B, 30C, 30D is filled with first cycle water (i.e., a valving system disposed between the dewatering system <NUM> and the fluid storage and supply system <NUM>). Alternatively or in addition, a valving system (not shown) may be used to transfer fluid between vessels 30A, 30B, 30C, 30D.

In some embodiments of the present disclosure, the hydro excavation vacuum apparatus is a mobile apparatus capable of recycling the water used for excavation such that the apparatus may be used to excavate one or more sites during daily use (e.g., for <NUM>, <NUM> or <NUM> or more hours) without re-filling with maiden water and/or disposing of reclaimed water. The apparatus <NUM> may include vessels that are filled with maiden water before excavation begins with relatively little empty tank space (e.g., with <NUM> gallon, <NUM> gallon, <NUM> gallon or more maiden water carrying capacity). The system may generate a vacuum of at least <NUM>" Hg at <NUM> standard cubic feet per minute. The dwell time of air passing through the separation vessel <NUM> may be less than about <NUM> seconds. A vibratory screen used to separate solids may have openings of <NUM> microns or less.

Compared to conventional apparatus for hydro vacuum excavating a site, the apparatus of the present disclosure has several advantages. The system may be adapted to process larger solids such as solids generated when a rotary wand is used to excavate a site (e.g., solids with a nominal diameter up to the size of the vacuum system conduits such as up to <NUM> (<NUM>")). The system may include a deceleration system having a deceleration vessel and deflection plate which allows solids to be quickly directed toward the airlock. The deceleration vessel allows a large volume of air and cut earth and water to be processed in a relatively compact vessel which reduces the footprint of the separation vessels to be reduced. The deceleration vessel may be more compact than a cyclone in which materials are vortexed as the cyclone should have a sufficiently large spoil material outlet to let larger solids to pass but typically only operate efficiently within a small range of length to diameter ratios. In some embodiments, a single deceleration vessel may be used which further reduces cost and the footprint of the dewatering system.

In embodiments in which the dwell time of air passing through the separation vessel is relatively small (e.g., less than about <NUM> seconds, <NUM> seconds or even <NUM> second or less), the solid material contacts liquid for a relatively small amount of time which reduces absorption of liquid by the solid particles which allows the particles to more easily travel over screens in downstream screening operations and allows at least some material to be processed before becoming a slurry which reduces water usage. Reducing dwell time also allows the size of the separation vessel to be reduced which reduces size and weight of the apparatus. In embodiments in which the airlock discharges directly to the dewatering screens of the dewatering system without intermediate processing (e.g., without centrifugation), the amount of time the solid earthen material contacts liquid may be further reduced which improves separation of solids from the liquid.

In embodiments in which the airlock has an outlet that tapers outwardly from a vertex, air may be pulled into the airlock near the vertex at a relatively high velocity, which causes the cut earthen material and water resting on the vane rotating into the opening to be agitated which promotes material to fall from the vane.

In embodiments in which the airlock includes a relatively small number of vanes (e.g., less than <NUM> or less than <NUM>) and corresponding pockets, relatively large solids may be processed through the airlock. The number of vanes and the vane length may be selected to allow the pockets to accommodate the largest size of cut earthen material that may fit through the vacuum conduit. In embodiments in which the airlock rotates relatively slowly (e.g., less than <NUM> RPM), the amount of air that passes into the airlock into the vacuum system may be reduced.

In some embodiments, the vacuum system includes a positive displacement vacuum pump to increase the capacity and the vacuum generated by the system to allow larger solids to be processed (e.g., generating a vacuum of at least <NUM> kPa (<NUM>" Hg) at <NUM> cubic meters (<NUM> cubic feet) per minute).

In embodiments in which the apparatus includes a fluid storage and supply system with a plurality of vessels in which maiden water and/or first cycle water is cycled through the vessels or includes a valving system to change the vessel from which excavation water is pulled, maiden water may remain separated from first cycle water with a reduced amount of tank space on the apparatus (e.g., a reduced amount of empty tank space after filling with maiden water before excavation has begun).

In embodiments in which the dewatering system includes a pre-screen that separates larger solids before the spoil material contacts a downstream vibratory screen (e.g., a pre-screen with large openings such the ratio of the size of the pre-screen openings to the size of the openings of the vibratory screen is at least about <NUM>:<NUM>), the downstream vibratory screen may be protected from impact with the large solids which reduces damage and fouling of the vibratory screen.

In embodiments in which the system includes a pitch and roll adjustment system with a pivot member that is laterally aligned with the outlet of the airlock, rolling of the screen (e.g., pre-screen, vibratory screen, or flat wire belt conveyor) caused by impact of material onto the screen is reduced or eliminated. In embodiments in which the pivot member is positioned rearward to a center plane of the screen (i.e., closer to the rear of the screen), the screen moves less near the airlock when the pitch of the screen is adjusted. This allows for less clearance between the screen and airlock and the vertical profile of the apparatus may be reduced. This also allows the spoil material to travel along a longer length of the screen which promotes separation of water from the spoil material.

By processing spoil material onboard the apparatus, solid materials may be separated to allow the spoil material (e.g., first pass water) to be more efficiently stored on the apparatus due to the smaller volume of the material. Separating solids allows the recovered water to be used for excavation in one or more cycles. Separated solids may be used for backfilling the excavation site which reduces the cost of the excavation operation and allows for efficient use of solids.

In embodiments in which the cyclonic separation system includes conveyors below the cyclones for removing material, the conveyors can remove material from the solids outlet of the cyclones which reduces or prevents pluggage of the cyclone outlets. Use of sealed conveyors and peristaltic pumps prevents air from entering the system from the ambient atmosphere.

In embodiments in which the fluid storage and supply system includes a manifold connected to the vessels of the system and valves that may be actuated to allow the vessels to be filled from the manifold, the first vessel pump may be operated to quickly fill additional tanks with maiden water through the manifold. Use of an airgap device prevents contamination of maiden water through backflow.

As used herein, the terms "about," "substantially," "essentially" and "approximately" when used in conjunction with ranges of dimensions, concentrations, temperatures or other physical or chemical properties or characteristics is meant to cover variations that may exist in the upper and/or lower limits of the ranges of the properties or characteristics, including, for example, variations resulting from rounding, measurement methodology or other statistical variation.

When introducing elements of the present disclosure or the embodiment(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," "containing" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., "top", "bottom", "side", etc.) is for convenience of description and does not require any particular orientation of the item described.

Claim 1:
A hydro excavation vacuum apparatus (<NUM>) for excavating earthen material comprising:
a wand (<NUM>) for directing pressurized water toward earthen material to cut the earthen material at an excavation site;
a vacuum system (<NUM>) for removing cut earthen material and water from the excavation site in an airstream;
a separation vessel (<NUM>) for removing cut earthen material and water from the airstream;
an airlock (<NUM>) that receives material from the separation vessel (<NUM>) and discharges the material through an airlock outlet (<NUM>); and
a dewatering system (<NUM>) for separating water from cut earthen material discharged from the airlock outlet (<NUM>), the dewatering system (<NUM>) comprising:
a slat assembly (<NUM>) that receives material directly from the separation vessel via the outlet (<NUM>) of the airlock (<NUM>), the slat assembly (<NUM>) comprising a plurality of slats (<NUM>) with openings formed between the plurality of slats (<NUM>) for separating material from the separation vessel (<NUM>) by size; and
a vibratory screen (<NUM>) for separating material that passes through the slat assembly (<NUM>) by size and falls from the slat assembly to the vibratory screen, the vibratory screen (<NUM>) having openings sized smaller than the openings between the plurality of slats of the slat assembly.