This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/084,922, filed Nov. 26, 2014, entitled INTEGRATED MUFFLER FOR HYDROVAC SYSTEM, the disclosure of which is incorporated hereby by reference herein in its entirety.

Hydrovac machines are (often) truck-mounted systems that spray water onto dirt at high pressure and utilize a high-strength vacuum system to lift the resulting water and dirt (i.e., mud) mixture. These systems are used for excavation, cleaning (of storm sewers and the like), and other purposes. A single tank disposed on the back of a truck includes a water-storage section and a debris-storage section. The system includes a blower that draws the mud into the debris section, where it is separated from the suction air. The suction air, now substantially free of debris, is filtered and drawn through the blower (which, again, creates the suction). Discharge air from the blower is passed through a muffler to reduce the sound at the muffler discharge outlet. Additionally, a bypass system is utilized to prevent the blower from dead-heading as it draws mud and debris during operation. The bypass system draws air from ambient, via a bypass muffler system, and into the blower inlet. This allows the blower to operate efficiently and reduces the risk of blower damage, as volumes of heavy mud and other debris are sucked up. In existing systems, the discharge and bypass mufflers are discrete insulated pipes into which high-velocity air is discharged or drawn through, respectively. They are typically disposed proximate the tank, above or below the blower.

In one aspect, the technology relates to an integrated tank having: a debris-storage chamber; a water-storage chamber; and a muffler system disposed proximate the water-storage chamber, wherein the muffler system includes: a bypass muffler; and a discharge muffler. In an embodiment, the water-storage chamber includes a water-storage chamber outer perimeter and wherein the muffler system has a muffler system outer perimeter substantially coextensive with the water-storage chamber outer perimeter. In another embodiment, the muffler system is substantially cylindrical. In yet another embodiment, a first sector of the muffler system defines the discharge muffler and a second sector of the muffler system defines the bypass muffler. In still another embodiment, both the bypass muffler and the discharge muffler each include a plurality of chambers.

In another embodiment of the above aspect, each of the plurality of chambers is separated by a baffle plate. In an embodiment, each of the baffle plates defines a plurality of openings and includes a plurality of vanes. In another embodiment, each of the bypass muffler and the discharge muffler includes an inlet in fluidic communication with a first chamber of the plurality of chambers and an outlet in fluidic communication with a second chamber of the plurality of chambers.

In another aspect, the technology relates to a muffler system for an industrial vacuum, the muffler system having: an outer housing at least partially defining a substantially cylindrical volume having a substantially circular cross section; a discharge muffler defined by a first sector of the substantially circular cross section; and a bypass muffler defined by a second sector of the substantially circular cross section. In an embodiment, the discharge muffler has a plurality of chambers separated by a plurality of baffles. In another embodiment, each of the plurality of baffles defines a plurality of openings and includes a plurality of vanes. In yet another embodiment, each of the plurality of chambers is defined by a subsector of the first sector. In still another embodiment, the discharge muffler further includes a discharge inlet into a first chamber of the plurality of chambers and a discharge outlet from a second chamber of the plurality of chambers.

In another embodiment of the above aspect, the discharge muffler further includes a third chamber of the plurality of chambers disposed between the first chamber of the plurality of chambers and the second chamber of the plurality of chambers. In an embodiment, the discharge muffler further includes a guide plate disposed in the first chamber of the plurality of chambers. In another embodiment, the discharge muffler includes a condensate drain. In yet another embodiment, the bypass muffler includes a plurality of chambers separated by a baffle defining a plurality of openings and having a plurality of vanes. In still another embodiment, the bypass muffler further includes a bypass inlet into a first chamber of the plurality of chambers and a bypass outlet from a second chamber of the plurality of chambers.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

FIG. 1 is a schematic view of an industrial hydrovac system 100. The hydrovac system 100 includes an integrated tank 102 that can be installed on the back of a commercial vehicle, such as a truck (not shown). Although vehicle-mounted hydrovac systems are more versatile, stationary systems are also contemplated for certain applications. The integrated tank 102 includes a plurality of sections. A debris-storage section, chamber, or tank 104 includes a cyclone or other structure to separate debris from suction air. A water-storage section, chamber, or tank 106 holds the water utilized in excavation processes. In certain embodiments, the water-storage section 106 may extend below the debris-storage section 104, so as to provide a pitched floor 108 in the debris-storage section 104 which may aid in draining the debris-storage section 104. The pitched floor 108 pitches towards a gate 110 or other drain that can be opened as required to drain the debris-storage section 104. A discharge muffler 112 is disposed proximate the water-storage section 106, and separated therefrom by a wall 114. The wall 114 may be manufactured of steel, which is similar in structure and thickness to the other walls that form the integrated tank 102. Steel having a thickness of about 0.25 inches is contemplated for certain applications, although other materials and thicknesses are contemplated. In one embodiment, ASME SA 516 Grade 70 Carbon Steel may be utilized. A bypass muffler 116 is disposed proximate the discharge muffler 112 and water-storage section 106. The integrated tank 102 is configured as described further herein, so as to appear visually as a single tank. This may be achieved by welding or otherwise securing the discharge muffler 112 and the bypass muffler 116 to an existing water and debris tank for a retrofit configuration, or an integrated tank 102 may be custom fabricated for particular applications.

During use, water is pumped via a water pump 118 through a water line 120 so as to be directed at an excavation site E. The water contained in the water-storage section 106 may be heated via a heat exchanger 122. The heat exchanger 122 may utilize an electric element or a fluid heat transfer element. In the latter case, the heat exchanger 122 may be connected to the coolant system of the vehicle. Use of a heat exchanger 122 may be desirable in environments where the hydrovac system 100 is exposed to extremely low ambient temperatures. Additionally, the water stored in the water-storage section 106 may be further heated by a flow of discharge air through the discharge muffler 112, as described in more detail below. As the high-pressure water loosens the dirt, sand, and rocks (these and other elements are referred to herein generally as debris or mud), a vacuum hose 126 is utilized to suction the debris from the excavation site E. The debris is drawn through the vacuum hose 126 and into the debris-storage section 104, where a cyclone and/or other structure separates the debris from the suction air. The suction air is drawn via a suction main 128 into a filter plenum 130. The filter plenum 130 is disposed upstream of a blower 132 that generates suction pressure. A filter 134 is disposed in the plenum 130 and filters any residual debris that may still be present in the suction air. A control valve 136 is also connected to the plenum 130 and is used to control the amount of vacuum generated in the suction line 128 (and therefore, at the vacuum hose 126). The control valve 136 may be two-way or variable position, and may be controlled electronically or manually. When fully closed, a maximum vacuum pressure is formed in the 

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