Patent Application
20090154287
Not applicable
Not applicable
I. Field of the Invention
The present invention relates generally to vehicle-mounted concrete mixing and dispensing systems including incline-mounted mixing drums and, more particularly, to on-board auxiliary fluid supply systems employed to supply water for washout or adding water and/or chemical additive to a concrete mix. Specifically, the present invention relates to a lightweight auxiliary tank for a fluid supply system shaped to nest beneath a raised portion of an associated inclined vehicle-mounted mixing drum and enables the addition of water and/or chemical additives to the drum or water to clean the drum from a compact on-board supply.
II. Related Art
Transit concrete mixing trucks, sometimes referred to as ready-mix trucks, have long been in use. They are equipped with large chassis-mounted rotatable mixing drums for mixing and dispensing a quantity of concrete. The drums typically are mounted on an incline and have an opening in the upper end for receiving ingredients to be mixed and discharging mixed concrete products. Loading is accomplished through a charge hopper which extends a distance into the opening of the drum. The drum is further provided with internal helical flights or fins extending around its internal surface which act to propel material forward and mix the concrete ingredients when the drum is caused to rotate in one direction and cause the mixed concrete to be discharged from the opening when the rotation of the drum is reversed. The lower portion of the drum includes a ring and roller system for drum support and rotation and the upper portion is carried by a heavy pedestal support assembly.
The trucks are generally further equipped with auxiliary water supply systems including supply tanks and distribution systems mounted on the trucks. These systems are necessary for several reasons. After mixing and discharge, the mixing drums retain an amount of residual concrete on the mixing fins and inner drum surface and discharge chutes which needs to be periodically washed out to prevent it from curing and hardening inside the drum and on external chutes. Therefore, it has become part of the operating routine to wash the interior of the drum and the discharge chutes one or more times per day. In addition, it is routinely necessary to add additional makeup water to adjust slump and/or amounts of chemical additives to concrete batches mixed in the drum prior to discharge.
Auxiliary water supply systems have included a water tank that has been typically pressurized to 50 psi or higher by a supply of air from a compressor carried on the truck. This, in turn, supplies water under pressure for washout or other uses through hoses and a valving system in a well-known manner. Alternatively, more recently, the pressurized system may be replaced by a pump assembly which eliminates the need to pressurize the tank.
To date, most auxiliary water tanks that have been used have been rather heavy metal structures which both are heavy and may add corrosion problems to the system. While aluminum tanks have been used and may reduce weight and corrosion problems, they remain relatively more expensive which is an additional drawback. Thus, there remains a need for an on-board auxiliary water supply and storage system that includes a relatively lightweight and inexpensive tank which does not corrode.
In addition, because space is at a premium for auxiliary on-board devices in transit concrete mixers, there also exists a definite need for an on-board auxiliary water tank that is located in an out-of-the-way unused location.
By means of the present invention, there is provided an auxiliary water supply system container or tank specifically configured to be disposed beneath a raised portion of a concrete mixing drum associated with a transit concrete mixing truck. The auxiliary water tank is fabricated of a polymeric material that is relatively lightweight and which will remain stable over time. The tank may be configured to be compatible with any on-board water distribution system and it is preferably designed to be compatible with a pumped system. Such a system may include a top discharge, bottom draw output system which includes a draw tube which is designed to connect to an external pumping system in a well known manner. The use of a pump obviates any need to pressurize the tank.
The water tank compartment is provide with a liquid level indicator which may be a transparent sight gauge and which may be calibrated in terms of volume and the compartment is generally provided with a single top fill capability. The tank is provided with a clamp down-type mounting system to removably fix it to the chassis of the transit concrete mixer.
In the drawings, wherein like numerals depict like parts throughout the same:
An embodiment of the present invention will be described with reference to certain drawing figures. They represent an example of an under-drum auxiliary water supply system for a transit concrete mixing truck which provides high pressure water for washout or additional water to be added to a mix in the drum. The embodiment described is meant as an example and not intended to limit the inventive concept in any manner.
It is an important aspect of the present invention that the limited space for auxiliary devices to be mounted on a transit concrete mixing truck be judiciously used. In accordance with another aspect of the invention, the auxiliary water tank of the invention is designed to be lightweight and stable when fixed in place, yet easily removed and reinstalled as desired. In addition, the auxiliary water tank of the invention is advantageously readily accommodated as an article of retrofit on existing transit concrete mixing vehicles.
A prior auxiliary water tank is illustrated in
The under drum auxiliary water tank itself is depicted in greater detail in
The tank further includes a pair of longitudinal, generally horizontal bottom grooves or recesses, as at 74 along the sides of the tank and a pair of spaced, generally vertically disposed recesses or slots 76 (
As can be seen from the figures, the tank 32 is totally accommodated in the space beneath the mixing drum and is shaped in accordance with the space available beneath the mounted drum. In addition, the tank does not protrude into space which can be utilized for other associated auxiliary devices. The tank can be readily connected with an on-board water pumping and distribution system in a well known manner and is easily connected and disconnected in place. The fill port 58 as shown in
The tank 32 may be molded of any stable, relatively high strength polymer material such as, for example, polyethylene. Successful models have been molded from high density polyethylene (HDPE) and this may be a preferred material. Other materials which are tough, chemically inert to the contents, which may include chemical additives, and can withstand the outdoor temperature swings are also suitable. The fastening latch devices 84 and the threaded members 86 are preferably metal, but may also be made from a high strength plastic material such as a polyamide, particularly a nylon.
The tanks 32 may be any convenient size and shape and may be custom fit with regard to the drum mounting of particular truck models. In addition, the auxiliary water tanks of the invention can be readily retrofitted and mounted on existing vehicles. In one typical embodiment, the water tank 32 is one with 135 gallon (511.3 liter) capacity.
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.
