Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-02-09
2001-05-08
Tong, Nina (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S611000, C340S626000, C340S691100, C116S06700A, C116S200000, C116S227000, C137S551000, C137S557000
Reexamination Certificate
active
06229447
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns generally the provision of an indicator assembly serving to signal the presence of pressurized gas in a gas supply line serving a using instrumentality.
A problem encountered by those using pressurized gas from a tank is the failure to shut off the gas supply and depressurize the supply line or conduit between the source and the using instrumentality, for example, a welding torch or a propane burner. In the interest of safety and economy it is of course always desirable to shut off a gas flow at the tank, a practice not always followed by gas users. While shutting off and depressurizing a gas supply line upon termination of a welding or other gas using operation is desirable, such may be overlooked with the result that line remains pressurized subjecting same to possible leaking. While pressure regulators in supply lines indicate line and/or tank pressure inspection of same at the end of a task is not always done. Still further, a malfunctioning control valve on an oxygen or propane tank could pressurize a non-operating gas supply line.
U.S. Pat. No. 4,121,615 discloses a mechanical indicator indicating loss of pilot gas pressure with provision for closing off communication between a fluid source and a remote actuator or valve. The valve control disclosed is operable by pilot presence and includes manual resetting of a valve stem to re-establish a primary gas flow.
U.S. Pat. No. 4,450,721 provides a method and an apparatus for indicating the weight and quantity of fuel in a storage container.
U.S. Pat. No. 4,596,980 discloses a valve having a stem responsive to pilot gas pressure and which stem, in the absence of pilot pressure, moves downwardly to permit a battery to energize an LED to indicate pilot pressure loss.
SUMMARY OF THE PRESENT INVENTION
The present invention is embodied in an indicator assembly for installation in a gas supply line to provide a signal as to the pressurized status of the supply conduit or line.
In the present indicator assembly a gas conduit segment is provided adjacent a pressurized gas tank or cylinder. The conduit segment is in communication with a pressure actuated switch which closes a circuit upon sensing system gas pressure to activate indicator means. The indicator means serves to inform a user of pressurized gas that perhaps a tank control valve has not been closed or is malfunctioning. The present indicator assembly includes a bleed valve to de-pressurize the gas supply at the termination of an operation. A check valve of the present indicator assembly prevents downstream residual gas from later re-pressurizing the indicator assembly providing an erroneous indication that the tank source is still serving the system.
Important objectives of the present invention include the provision of a conduit segment in a supply line or conduit having a pressure responsive switch which completes a circuit to indicator means in the presence of a set point pressure existing in the line; the provision of an indicator assembly for use with a pressurized gas source to provide a signal that the gas supply line from the source is still pressurized even though the welding or burner operation has been terminated to serve as a reminder to an operator to close a tank valve or pressurized gas from another source; the provision of an indicator assembly which signals, in one embodiment, that undesired residual gas pressure exists in a gas supply line or conduit subsequent to operation of a gas using appliance such as a welding torch or a propane burner.
REFERENCES:
patent: 3782168 (1974-01-01), Wailes
patent: 4025235 (1977-05-01), Newbrough
patent: 4051920 (1977-10-01), Reinsma
patent: 4064855 (1977-12-01), Johnson
patent: 4121615 (1978-10-01), Bergeron
patent: 4450721 (1984-05-01), Gaunt et al.
patent: 4596980 (1986-06-01), Bergeron
patent: 5281100 (1994-01-01), Diederich
Hand C. Gene
Redhead Paul M.
Givnan, Jr. James D.
Tong Nina
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