Fluent material handling – with receiver or receiver coacting mea – Automatic control of flow cutoff or diversion – Level or overflow responsive
Reexamination Certificate
2000-01-13
2001-01-30
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Automatic control of flow cutoff or diversion
Level or overflow responsive
C141S198000, C137S484200, C137S500000
Reexamination Certificate
active
06179020
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to automatic shutoff valves controlled by the fluid level in a container.
2. Prior Art
When filling a container with a fluid dispensing device, such as a water gun, an operator must closely monitor the fluid level. The valve on the dispensing device, such as a trigger, must be manually kept open for a prolonged period, and manually closed when the desired fluid level is reached. This method is time consuming when filling a large container, and tedious when repeatedly filling multiple containers.
Numerous automatic shutoff valves are known for shutting off flow when a predetermined fluid level is reached in a container being filled. They are particularly useful for automatically filling the cells of a lead-acid battery to a predetermined level. However, they are relatively complicated and expensive to produce.
A simpler automatic shutoff valve is shown in U.S. Pat. No. 4,556,093 to Jones, and is arranged inside a dispensing device. It includes a movable tube connected to the downstream end of a constricted venturi, which directs a jet of fluid along the inside wall of the tube. A ball positioned upstream of the venturi is connected to the movable tube by a wire. The ball is kept away from the venturi by a spring. The venturi causes fluid flowing there through to substantially increase in velocity and decrease in pressure relative to the liquid at the upstream end thereof. Before the fluid level in the container reaches the lower end of the dispensing device, the pressures between the upstream and downstream ends of the venturi are equalized by outside air flowing into the movable tube from the lower end of the dispensing device. When the fluid level in the container reaches the lower end of the dispensing device, air can no longer enter the movable tube to equalize the pressure. The low pressure of the fluid jet draws the movable tube away from the venturi. The spring loaded ball is pulled against the venturi, and fluid flow is shut off. However, the movable tube cannot slide smoothly because it is only guided at the upstream end by the venturi. The downstream end would wobble in the jet and cause the upstream end to stick to the venturi. The valve is relatively long, so that it can fit a limited variety of dispensing devices. Also, the single venturi limits flow rate to a relatively low level.
OBJECTS OF THE INVENTION
Accordingly, objects of the present automatic shutoff valve are:
to be compact and easily installed in a variety of fluid dispensing devices;
to remain open when the fluid level in a container being filled is below a predetermined level;
to automatically close and shut off the dispensing device when the fluid level reaches the predetermined level;
to operate smoothly and reliably; and
to be very simple to produce.
Further objects of the present invention will become apparent from a consideration of the drawings and ensuing description.
BRIEF SUMMARY OF THE INVENTION
The present fluid level controlled automatic shutoff valve is comprised of a tubular housing with an axial bore which has an upstream closure, a downstream opening, and an annular piston seat at the downstream opening. A movable piston is positioned in the bore, and biased to a retracted position by a tension spring connected between the piston and the closure of the bore. A plurality of channels on the wall of the housing extend between an upstream end of the housing and the bore. The channels terminate in venturis downstream of the piston in the retracted position. The shutoff valve is positioned in a fluid dispensing device. When pressurized fluid is delivered through the dispensing device, the fluid is directed through the channels and out the venturis at high speed and low pressure. Before the fluid level in a container being filled reaches an open lower end of the dispensing device, the pressures between the upstream and downstream ends of the piston are balanced by air flowing into downstream opening of the bore from the open lower end of the dispensing device. When the fluid level reaches the open lower end of the dispensing device, the air flow is cut off, and the low pressure fluid from the venturis pulls the piston into the seat at the downstream opening of the bore. Fluid flow is shut off.
Douglas Steven O.
Lo Jack
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