Additive dosing assemblies and hydro excavation vacuum apparatus incorporating same

1 . A hydro excavation apparatus for excavating earthen material comprising:

a first reservoir for holding a base fluid therein;

a second reservoir for holding an additive therein;

a vacuum system for removing earthen material from an excavation site;

an additive dosing assembly including at least one of a pump and a valve fluidly connected to the second reservoir, the additive dosing assembly being selectively controllable to introduce the additive into the base fluid to form a mixed fluid solution;

a wand for directing the mixed fluid solution toward earthen material at an excavation site to cut the earthen material;

a sensor for detecting a flow of fluid between the wand and the first reservoir; and

a control system communicatively coupled to the additive dosing assembly to control addition of additive into the base fluid based at least in part on the sensor detecting fluid flow between the wand and the first reservoir.

2 . The hydro excavation apparatus of claim 1 , wherein the additive dosing assembly is configured to introduce the additive into a pressurized fluid line containing the base fluid.

3 . The hydro excavation apparatus of claim 1 , wherein the additive dosing assembly is configured to introduce the additive into the base fluid in at least one of a non-pressurized fluid line and a non-pressurized chamber.

4 . The hydro excavation apparatus of claim 1 further comprising an excavation component for receiving the removed earthen material, wherein the additive dosing assembly is configured to introduce the additive into the removed earthen material within the excavation component.

5 . The hydro excavation apparatus of claim 4 , wherein the excavation component is configured to provide a negative pressure environment and wherein the additive dosing assembly is configured to introduce the additive into the negative pressure environment of the excavation component.

6 . The hydro excavation apparatus of claim 1 further comprising a chamber for storing the removed earthen material.

7 . The hydro excavation apparatus of claim 1 further comprising:

a separation vessel for removing the earthen material and mixed fluid solution from an airstream of the vacuum system; and

a dewatering system for separating fluid from the removed earthen material received from the separation vessel.

8 . The hydro excavation apparatus of claim 7 , wherein the additive dosing assembly is configured to introduce the additive into at least one of the separation vessel and the dewatering system.

9 . The hydro excavation apparatus of claim 1 further comprising a collection reservoir for storing the removed earthen material therein, wherein the additive dosing assembly is configured to introduce additive into the earthen material upstream of the collection reservoir.

10 . The hydro excavation apparatus of claim 1 , wherein the additive dosing assembly includes the pump, the pump having a motor, and wherein the control system is communicatively coupled to the motor, the control system being selectively adjustable to control a speed of the motor, and wherein changing a speed of the motor changes a rate at which the pump introduces the additive into the base fluid.

11 . The hydro excavation apparatus of claim 1 , wherein the control system comprises a selectively positionable switch for activating the additive dosing assembly.

12 . A hydro excavation apparatus for excavating earthen material comprising:

a reservoir for holding a base fluid therein;

an additive dosing assembly for introducing an additive into the base fluid to form a mixed fluid solution;

a wand for directing the mixed fluid solution toward earthen material at an excavation site to cut the earthen material;

a vacuum system for removing the cut earthen material and the mixed fluid solution from the excavation site;

a sensor for detecting a flow of fluid between the wand and the reservoir; and

a control system communicatively coupled to the additive dosing assembly to control addition of additive into the base fluid based at least in part on the sensor detecting fluid flow between the wand and the reservoir.

13 . The hydro excavation apparatus of claim 12 , wherein the additive dosing assembly comprises a positive displacement pump and a motor operatively connected to the positive displacement pump.

14 . The hydro excavation apparatus of claim 12 further comprising an excavation fluid pump fluidly connected between the reservoir and the wand and operable to pressurize fluid supplied to the wand.

15 . The hydro excavation apparatus of claim 12 , wherein the control system comprises:

a selectively positionable switch for activating the additive dosing assembly;

a pulse width modulation (PWM) driver including a PWM module for regulating an effective applied voltage provided to the additive dosing assembly, the PWM module further including a dial for selectively adjusting a setting of the PWM module; and

a relay communicatively coupled to the sensor and the additive dosing assembly.

16 . A method for controlling a hydro excavation apparatus, the method comprising:

providing a base fluid reservoir storing a base fluid therein;

providing an additive dosing assembly including at least one of a pump and a valve that is fluidly connected to an additive reservoir storing an additive therein;

controlling, by a control system communicatively coupled to the additive dosing assembly, the additive dosing assembly to selectively introduce the additive into the base fluid to form a mixed fluid solution;

cutting earthen material at an excavation site using a wand to direct the mixed fluid solution toward the earthen material;

controlling a vacuum system to remove the cut earthen material and the mixed fluid solution from the excavation site; and

detecting, by a sensor, a flow of fluid between the wand and the base fluid reservoir, wherein the control system controls addition of additive into the base fluid based at least in part on the detected fluid flow between the wand and the base fluid reservoir.

17 . The method of claim 16 , wherein controlling the additive dosing assembly comprises introducing the additive into a pressurized fluid line containing the base fluid.