Patent ID: 7628295

Claim:
An apparatus for permitting a substantially continuous flow of drywall compound to a wallboard joint comprising: a delivery tube for delivering drywall compound completely therethrough, the delivery tube having a first end connected to a drywall compound supply assembly fed directly by drywall compound pressurized from a source, and a second end opposite the first end in communication with a drywall compound dispensing head, there being a normally closed, pneumatically pressure operated valve arrangement interposed between the second end of the delivery tube and the dispensing head for controlling the starting and stopping of drywall compound flow between the delivery tube and the dispensing head, the pneumatically pressure operated valve arrangement being normally and automatically closed by a continuously applied stored preset force independent of the source for pressurizing the drywall compound, pressure of the drywall compound in the delivery tube overcoming the preset force of the valve arrangement to provide a substantially continuous flow of drywall compound to the dispensing head, wherein the valve arrangement includes a pinch valve having a flexible diaphragm provided with a closing pressure for controlling the flow of pressurized drywall compound through the pinch valve, and wherein the pinch valve is joined to and in communication with a one way flow control valve and a normally closed precharged air reservoir located away from the drywall compound flow for storing an amount of precharged air therein, the air reservoir having a pressure gauge and a charging valve and cap unit adapted to be connected to a source of pressurized air.