Fluid handling – With indicator – register – recorder – alarm or inspection means – Fluid pressure responsive indicator – recorder or alarm
Reexamination Certificate
1999-09-27
2001-05-01
Lee, Kevin (Department: 3753)
Fluid handling
With indicator, register, recorder, alarm or inspection means
Fluid pressure responsive indicator, recorder or alarm
C137S113000, C137S351000
Reexamination Certificate
active
06223769
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to pressure-sensing and indicating units for gas systems and, more particularly, to remote indicator units for indicating the full/empty status of at least one pressurized gas source such as an L.P. gas tank.
Automatic changeover two-stage LP gas regulators are widely known and used to provide gas to selected appliances at a stepped-down pressure. Automatic changeover regulators, such as the Marshall Gas Controls Model 250, typically include a high-pressure changeover regulator that includes at least one inlet for receiving gas from a pressurized container, reduces the gas pressure to a first predetermined level, and transmits that gas to a second, low-pressure regulator. The low-pressure regulator further reduces the gas pressure to a predetermined level prior to conveying the gas through an outlet to, e.g., an appliance.
In many applications, and particularly in the Recreational Vehicle (“RV”) field, at least two gas source containers (a “supply” container and a “reserve” container) are connected to at least two corresponding inlets at the first high-pressure regulator, each inlet for receiving gas from a different gas source container. During use of the connected appliance, when the supply container becomes depleted of gas, the regulator automatically changes over to the reserve container such that the reserve container becomes the “new supply” container for providing gas to the regulator. After such a changeover, the original supply container can be disconnected from the corresponding inlet of the regulator and be refilled.
To notify the user of a changeover to the reserve container, known regulators of this type preferably have a mechanical full/empty indicator attached to the high-pressure regulator. This indicator typically includes a pressure-sensitive member, e.g., a diaphragm, that is responsive to the pressure of the gas received through the inlet associated with the supply container. The indicator also typically includes a bi-colored or other such indicator member that is mounted and displayed in a transparent capsule attached adjacent to the high-pressure changeover regulator such that the indicator member abuts or is coupled to the diaphragm. As the diaphragm moves (i.e., deflects) in response to changes in pressure, the diaphragm exerts a force on the bi-colored member. As a result, the diaphragm causes translational movement of such member to display a portion of the member having a color indicative of the “full/empty” status of the supply container. For example, when the supply container is depleted of gas after extensive use, the low gas pressure sensed by the diaphragm causes the diaphragm to deflect accordingly and thus cause corresponding movement of the bi-colored or other indicator member to display a portion of such member that indicates that the supply container should be disconnected and refilled.
A shortcoming of such mechanical full/empty indicators is that the regulator and gas supply containers are typically stored at a remote location that is not often or typically accessed, e.g., outside the cab or occupied interior space of a recreational vehicle, such that the user has to exit the cab and make a special effort to inspect the gas containers, including the regulator and indicator attached thereto, to determine whether the automatic changeover has been triggered. Since the supply system is usually placed out of the way, e.g., behind doors, in a cabinet, etc., the full/empty indicator is not ordinarily viewable. Since the changeover is automatic and only occurs at spaced intervals and on an irregular basis, and may occur at night, the condition may go undetected for some time, leading to unexpected depletion of the reserve container.
Therefore, an indicator is needed that conveniently notifies the user at an often-occupied remote location that the supply container is at or near empty, such that the user does not have to continuously and unnecessarily check the full/empty status of the gas container(s) at their out-of-the-way location. The desired indicator should also be inexpensively retrofittable to commonly known gas systems, such as those using the Marshall Gas Controls Model 250 switching regulator, but also could be manufactured as part of the regulator for new installations.
SUMMARY OF THE INVENTION
The present invention overcomes the disadvantages of and improves upon known gas systems by providing a sensing apparatus for generating a transmittable signal indicative of whether a gas container, and especially one connected to a conventional two-stage LP gas regulator, is at or near empty. In a preferred embodiment, the sensing apparatus converts the mechanical movement of a conventional full/empty indicator into an electrical signal and transmits that signal to an indicator at a remote location for indicating whether the gas container is depleted or empty; for example, by actuating a lighting element. The sensing apparatus is directly retrofittable to known regulators, without modifying the regulator, to provide a cost effective device that can be readily attached to an existing gas supply system.
According to the preferred embodiment, the sensing apparatus is an improvement on the mechanical full/empty indicator included on a conventional two-stage changeover-type gas regulator that has at least two inlets for receiving gas from at least two gas storage containers. The sensing apparatus includes a sensor housing disposed on the full/empty indicator and releasably connected to the regulator. A sensor is mounted in the sensor housing and is responsive to the movement of the full/empty indicator by generating an output signal indicative of the gas pressure sensed by a diaphragm of the indicator.
According to another aspect of the invention, the sensor includes a plunger and a switching element, both maintained within the sensor housing, wherein the plunger is coupled to the indicating member of the mechanical full/empty indicator such that the plunger is conjointly movable with the indicating member in response to the pressure sensed by the diaphragm. Notably, at least a portion of the plunger is or has a magnetic material and the switching element is magnetically responsive such that position of the plunger controls the conducting state of the switching element for generating an output signal indicative of the gas pressure sensed by the diaphragm.
According to a still further aspect of the invention, a sensing and indicating apparatus for a changeover gas regulator includes the housing and sensing device of the preferred embodiment for converting the mechanical movement of at least a portion of the full/empty indicator into an electrical signal indicative of the gas pressure sensed by the diaphragm of the full/empty indicator. In addition, the apparatus includes an indicator, such as a lighting element, that is responsive to the electrical signal. For example, when the main or principal gas container is at or near empty, the sensed gas pressure is low and the sensing apparatus transmits an output signal to the indicator notifying the user that a changeover to a reserve container has occurred and that the initially selected supply container requires refilling.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.
REFERENCES:
patent: 2747042 (1956-05-01), Zimmerman
patent: 2772409 (1956-11-01), Reid
patent: 3101068 (1963-08-01), Jensen
patent: 3517693 (1970-06-01), Dietz
patent: 3549837 (1970-12-01), Barnes et al.
patent: 3965317 (1976-06-01), Gratzmuller
patent: 4181835 (1980-01-01), Stadler et al.
patent: 4223692 (1980-09-01), Perry
patent: 4450721 (1984-05-01), Gaunt et al.
patent: 4603707 (1986-08-01), Gregoire et al.
patent: 4763114 (1988-08-01), Eidsmore
patent: 4921008 (1990-05-01), Foster
patent: 4989832 (1991-02-01), Kremer
patent: 4993451 (1991-02-01), Kremer
patent: 5019678 (1991-05-01), Templeton et al.
paten
Bragg John C.
Heckler Ruth H.
Lee Kevin
Price Heneveld Cooper DeWitt & Litton
S. H. Leggitt Company
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