Fluent material handling – with receiver or receiver coacting mea – Automatic control of flow cutoff or diversion – Level or overflow responsive
Patent
1979-09-24
1982-05-25
Schmidt, Frederick R.
Fluent material handling, with receiver or receiver coacting mea
Automatic control of flow cutoff or diversion
Level or overflow responsive
141217, B65B 328, B65B 5714
Patent
active
043311873
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a liquid dispensing device, and particularly to a device having the form of a so-called pistol nozzle or pistol valve, such nozzles or valves normally being used in association with petrol pumps at vehicle filling stations.
Such pistol valves comprise a valve housing having an inlet and an outlet, a valve for controlling the flow of liquid from the inlet to the outlet, a discharge pipe connected to the outlet, and a manually operable operating mechanism for controlling movement of the valve, said operating mechanism including adjustable means which can be adjusted or moved between an active or engagement position and an inactive or free position. The operating mechanism normally has the form of two plungers which are axially moveable in the valve housing and one of which is arranged within the other. In the rest position, the outer plunger forces the valve into sealing abutment with a valve seating under the action of a relatively heavy spring. Each of the plungers is provided with a respective recess which lie opposite each other in said rest position. The inner plunger is moved axially by operating an outer operating handle. The outer plunger can be caused to accompany the inner plunger during said axial displacement thereof owing to the fact that in said rest position two rollers carried by a holder are urged downwardly through the recess in the outer plunger and into the recess in the inner plunger. Thus, in this position the rollers couple the two plungers together in a manner such that the outer plunger will accompany the axial movements of the inner plunger when the operating handle is activated. Such an axial displacement of the outer plunger allows the valve to be subsequently opened by an overpressure at the inlet.
In previously known pistol valves of this type, the holder carrying said rollers is normally spring biased towards its engagement position with said inner plunger. Thus, the handle need only be moved to the neutral position in order to be able to open the valve, meaning that the recesses of the plungers are located opposite each other and that said rollers will be pressed into said recesses by means of said spring. Subsequent depression of the handle will cause the valve to open as soon as the requisite pressure prevails at the inlet.
The main function of the rollers is to permit the valve to close as soon as the level of liquid in the tank has reached a certain position on the discharge pipe of the piston valve. To this end, the holder carrying said rollers is attached to a diaphragm which is arranged to curve upwardly to remove the rollers from the said engagement position with the inner plunger, when an underpressure is obtained in a chamber arranged above said diaphragm, said chamber communicating with an opening arranged at said position on the discharge pipe. If the handle is still held depressed, the inner plunger will remain in its axially displaced position while the outer plunger will be returned by its associated spring, thereby causing the valve to seal against its valve seating.
Pistol valves of this type thereby prevent overfilling of the tank, by automatically interrupting the flow of liquid thereto, and hence in manually serviced filling stations these pistol valves are normally provided with latching means by means of which the handle can be held depressed to permit filling of the tank to continue whilst the attendant carries out other servicing details on the vehicle. In the case of filling stations which are not serviced by skilled personnel and in which supervision of the pumps is of a relatively poor standard, the provision of means for latching the handle in the filling position is not permitted, since carelessness or acts of ill will can result in large quantities of petrol flowing out immediately a pump is actuated. For example, this can occur when the operating handle is depressed and latched in its depressed position by some person or other, subsequent to the pump being deactivated after a filling operation. This latching of th
REFERENCES:
patent: 3077212 (1963-02-01), Hearn
patent: 3323560 (1967-06-01), Ehlers
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