Patent Application
20070086270
I. Field of the Invention
The present invention relates generally to systems for washing out concrete mixing drums to remove residual concrete products from such drums and, more particularly, to an integral washout system including a guide device mounted in fixed relation to such a drum that is particularly suited to vehicle-mounted mixing drums including non-metallic drums.
II. Related Art
Transit concrete mixing trucks, sometimes referred to as ready-mix trucks, have long been in use. They are equipped with a large chassis-mounted rotatable mixing drum 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 (charging) concrete products. Loading is accomplished through a charge hopper which extends a distance into the opening of the drum. The charge hopper may be designed to pivot and swing clear of the opening during the discharging operation. The drum is further provided with internal helical flights or fins extending around its internal surface which acts to mix the concrete when the drum is caused to rotate in one direction and cause the concrete to be discharged out of the opening when the rotation of the drum is reversed. The upper portion of the drum includes a ring and roller system for drum support and rotation that is carried by a heavy pedestal support assembly. After mixing and discharge, such concrete mixing drums retain an amount of residual concrete on the mixing fins and inner drum surface which needs to be periodically washed out to prevent it from curing and hardening inside the drum. Therefore it has become part of the operating routine to wash the interior of the drum one or more times per day. It has further become a common practice to use external manually operated devices to accomplish the washout task. Manual cleaning has typically involved a worker entering the drum with a water hose and hand tools to clean the drum.
Independent external probe and nozzle devices have also been proposed such as that shown in U.S. Pat. Nos. 6,418,948 and 6,640,817 to Harmon. A further truck-mounted system for washing a charge hopper and discharge chute with provision for containing and filtering rinse water is shown in U.S. Pat. Nos. 6,155,277 and 6,866,047 to Barry or Marvin. Those systems rely on manual manipulation of flexible conduits for both washing and collection.
While some of these devices have met with a degree of success, there remains a need for a washout system that is permanently mounted with respect to the drum as a part of a mixer system. That would further reduce the need for manual interaction and the risk of equipment damage by ensuring that the washout hose remains clear of both mixing fin and charge hopper when the mixer is operated during cleanout.
By means of the present invention, there is provided an integrally mounted apparatus particularly suitable for washing out vehicle-mounted concrete mixing drums. The washout apparatus includes an open-ended elongate, relatively rigid shaped hollow guide tube mounted in fixed relation to the support structure support for a mixing drum and extending to a point within and in fixed relation to the opening in the upper end of the drum between the fins and charge hopper. A flexible hollow hose is threaded through the guide tube. The hose has a receiving end connected with a source of cleaning fluid under pressure and a discharge end which protrudes from the end of the guide tube as it ends inside the open end of the mixing drum. A forward hose stop in the form of a clamp-on device of a larger diameter than the guide tube is provided for preventing the hose from slipping back down through the guide tube and a similar rear hose stop is provided for limiting the travel of the discharge end of the hose outward from the end of the guide tube.
The source of cleaning fluid under pressure, is normally a water supply tank carried on the transit mixer truck which is provided with an associated pump outlet manifold and valving system to supply fluid under pressure through a manually operated valve to the connected flexible hose.
The guide tube and hose are preferably of non-metallic material, the guide tube being preferably PVC tubing and the hose can be of garden hose material.
In the drawings wherein like numerals depict like parts throughout the same:
The detailed description portrays an example of the washout system of the invention that is meant to illustrate the inventive concepts but is not intended to limit the scope of the invention. With this in mind, the details will now be described
The guard tube 32 is fixed to the sidewall 68 of the access platform 64 as by EMT clips 72 and is thought to extend through the mixer guard grid arrangement to be positioned so that the end of the curved section 74 of the guide tube 32, which may be a street elbow, is located between the helical mixing fins shown at 76 and the charge hopper 54. Clearance must be maintained between the washout system and the charge hopper during charge hopper movement particularly when it is in the lowered or charge position as shown in the figures and also in the discharge (pivoted away) position. The guide tube of the system must also clear the mixing fins and clear concrete being discharged from the opening. The forward hose stop 36 is positioned near the discharge end of the hose and prevents the washout hose 28 from slipping back through the guide tube 30. The washout hose 28 can be extended to protrude a distance into the mixing drum until the rear hose stop 38 engages the lower end 78 of the guide tube 32.
Guide tube 32 may consist of a straight section 80 connected to a second street elbow 82 and a short nipple 84 connected to street elbow 74. The guide tube is preferably a non-metallic rigid material such as PVC tubing and is typically about 2″ (5.08 cm) in diameter.
An important aspect of the washout system of the present invention involves the use a permanently mounted guide tube associated with the washout operation. This eliminates the need for a separate auxiliary device which is used to access the charge/discharge opening of the mixer. It also eliminates the need for an operator to carefully steer a cleanout device between the charge hopper and mixing fins each time washout is required.
It should be noted that as shown in
To operate the cleanout system, the pump 14 is activated prior to cleanout and the valve 22 opened after removal of cap 40 so that cleanout fluid under high pressure can be blasted into the drum with the operator extending the base 28 into the drum and/or adding tools to the discharge end of base 28 as desired. The hose is withdrawn and the drum operated to rotate in the mixing direction to clean residual material from the internal surface. The rotation of the drum is then reversed and the cleanout fluid (normally water) is discharged with the residual material as slurry.
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 such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
