This application claims the benefit under 35 USC 119(e) of U.S. provisional No. 61/233,402 filed Aug. 12, 2009.

Hydro-Vac Excavation

Hydro-Vac Excavation is becoming a common practice when working with underground infrastructure. Hydro-Vac excavation adds water to the excavation while vacuuming up the mud created by the added water in order to excavate. This enables excavation to be less destructive than using other digging techniques. There is demand for commercially sound and economical equipment in the industry so that the costs to hydro-vac is affordable.

The unique design of the Prism Hydro-Vac allows good performance but keeps the construction costs and weight down on the Hydro-Vac trucks. The Prism Hydro-Vac is a new approach to constructing a Hydro-Excavator. There are many benefits to the Prism Hydro-Vac but this patent document focuses on the mud tank as the prime advantage, that makes the construction of the Prism Hydro-Vac much easier, lighter and more cost effective.

In an embodiment, there is provided an excavation apparatus, comprising a mud tank having an input for debris, water and air; a hose connected to the input of the mud tank; and a blower attached to the mud tank. The blower is configured to blow air out of the mud tank to establish a negative pressure within the mud tank in operation so that air, water and debris will be sucked into the mud tank through the hose. The blower is located in a recessed portion of the periphery of the mud tank, the recessed portion of the periphery of the mud tank being located in an upper part of the mud tank.

These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.

The mud tank 20 of the Prism Hydro-Vac, an embodiment, is 10? long at its longest point and is 8? in diameter. It has a hinged pivoting point 22 at the back and is lifted with a cylinder at the front like a gravel box to dump. The rear door 24 is big, taking the bottom half as the door which makes dumping mud very easy. The front 26 of the tank is flat and has flat bars on the edge to make it strong enough to withstand the vacuum force that is applied to it. The sections 28 in between these flat bars are used as the air discharge silencers 30 of the blower 32. This is a natural use for these areas and compartments to silence the blower exhaust. This means there is no piping or other silencers needed to be added to the system.

There is a portion of the top, front part of the mud tank 20 that is boxed and open to the top. The blower 32 sets down in this recessed portion 34 of the tank which is normally wasted air space anyway. By mounting the blower 32 up in this section of the tank area, it is out of the way, it uses up wasted space and it doesn't require any piping and ducting to be used which makes the construction of the Hydro-Vac much cheaper, and makes it function way better, lighter and very easy to maintain. The blower 32 is laid in a horizontal position so all liquids and particles will fall through it as it is running or when it is shut down. All the air starts high, drops into the blower, goes down through the blower, out of the bottom of the blower and down through the silencing chambers which are in between the flat bars at the front of the tank. Everything runs through and out and does not ever create a low spot liquid trap.

What makes this design so unique is the fact that it is inset into the top of the mud tank which enables Prism to reduce the needed space on deck and utilize otherwise wasted space in the tank. This eliminates the need for piping and complex separation systems.

Another feature is the clean screen curtain 36 that is in the tank 20 that contains the flying mud debris entering the tank through the inlet 38 from the boom 40 and ultimately from the hose 42 connected to the boom 40. This eliminates the need for cyclones and other complicated ways to stop debris from getting into the blower.

Thus, in an embodiment, the new design is based on the blower being mounted right in a cut out that is in the tank in the void air space at the top of the tank which uses otherwise wasted space, eliminates all the piping going to and from the blower making it suck harder due to no piping pressure drop. Since there is no piping required they are lighter and easier to build which makes them cheaper to sell. The blower silencers may be incorporated right into the tank frame so that you can not see them, they are also using otherwise wasted space and they are much cheaper to build. This tank may be hoist to dump so it is very user friendly.

The air flow of the Prism Hydro Vac is preferably in a downwardly direction. Once the air is being vacuumed out of the tank and goes through the blower, the air goes down hill and vents out the bottom. This feature eliminates fluid buildup in the piping, blower and scrubber again making things cheaper and easier to produce. These features allow a manufacturing advantage that saves money, weight and complexity.

Depending on the embodiment, the blower 32 can reside on the outside of the outer shell 42 of the tank, as for example in a recessed portion 44 of the outer shell of the tank as shown in FIG. 3A, or it can reside inside the outer shell 42 of the tank, in a portion of the tank cut off from the main body of the tank by inner boundaries 46, as shown in FIG. 3B. In the former case, there may be a covering 48 over the blower. In the latter case, even though the outer shell might be constructed first and the blower and inner boundaries added later, the inner boundaries are the new periphery of the tank, and thus the blower is still in a recessed portion of the periphery of the tank.

Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims. In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.