Measuring and testing – Liquid level or depth gauge – Sight glass
Reexamination Certificate
1999-10-06
2001-05-22
Williams, Hezron (Department: 2856)
Measuring and testing
Liquid level or depth gauge
Sight glass
C073S325000, C073S332000
Reexamination Certificate
active
06234018
ABSTRACT:
TECHNICALL FIELD
The present invention relate s to devices and methods for sight gauges and more particularly to a safety sight gauge for visually inspecting liquid level or presence in vessels and sight flow monitoring for piping systems, reactors and the like. The present invention is a transparent sight tube gauge positioned between two coaxially aligned check valves, a two piece check valve push rod is axially disposed and supported in the bore of the sight tube and extends about the length of the sight tube and urges both check valves open. When the sight tube is cracked or broken, the push rod collapses and allows the check valves to close. An outer tubular shield protects the sight tube and forms an interstice between the sight tube and outer tube which is in communication with a diaphragm at one end of an adjustable check valve actuator which moves the check valves to a closed position when a leak occurs within the interstice.
BACKGROUND ART
Liquid sight indicators are used as liquid level gauges for vessel inventory estimation and sight flow monitors for piping system flow indication (bull's eye), or as observation sites for process equipment such as reactors, heaters, storage vessels and the like. Sight gauges are typically externally mounted on a vessel or pipe and connected between two mounting blocks attached within the range of liquid movement to indicate the presence and/or level of liquid therein. Gauges for visual indication employ transparent tubular conduits of an inert substance such as glass mounted between the mounting blocks. Breakage of the glass tube is a concern.
Many inventors have described sight gauges that improve safety by externally shielding the glass sight tube. These inventions are extremely useful for their stated purposes however they do not include a leak shut off system as the present invention which trips coaxially aligned check valves to a closed position when pressure changes, caused by a leak, occur in the gauge. Examples of prior art sight gauges are described in the following patents:
Wolf, U.S. Pat. No. 5,648,607 describes a replaceable sight gauge assembly which includes two bolt assemblies. Each bolt assembly includes an entry bolt and an exit bolt, the entry bolt houses a valve which is opened when the exit bolt is mated therein, the valved bolts provide a means for replacing the sight gauge.
Sheridan U.S. Pat. No. 5,628,231 describes a sight glass for steam boilers which includes and flanges provided with molded inserts which serve to provide sealing means engaging the end surface of a sight glass. A concentrically disposed guard tube is also maintained in sealed relation to the end flanges. Tie rods to prevent excess tightening of the ended flanges are also provided.
Mills, U.S. Pat. No. 5,442,159 describes a sight gauge positioned between two spaced apart compression fittings which receive an elongated tubular transparent tube shield and a slightly longer concentrically placed sight tube.
Newman, U.S. Pat. No. 5,323,654 describes a shielded sight glass positioned between two spaced apart confronting fitting which is shielded by a polygon impact resistant plastic enclosure.
Gruett U.S. Pat. No. 5,323,653 concerns a method for mechanically supporting a shield for a liquid gauge. The apparatus includes a support member, first and second end blocks which are slidable engagable with the support member while each has a passage way, sealborne by each of the end blocks and disposed in each of the passage ways and a transparent tube telescopingly received in the respective passage ways and defining a fluid passage way or chamber.
Bertani, U.S. Pat. No. 5,383,360 describes a column type level indicator with a means for its outward mounting through fixing screws with axial and transvese holes therethrough which act as ducts into the sight tube.
Ford et al. U.S. Pat. No. 5,052,224 describes a shielded vertically mounted sight gauge with a transparent pipe extending between housings, while each housing includes a flange for receiving a larger transparent shielding pipe, one flange telescopingly receives the shield with a biasing means that urges against the shield pipe so that the flange can be moved away from the shield pipe and access gained to the sight tube.
Sheridan et al. U.S. Pat. No. 4,838,095 describes a sight glass with sampling system and includes an inner transparent glass tube an outer concentric shield tube forming an interstices between the tubes and a drain for remaining leakage caused by fracture of the inner tube.
Mills U.S. Pat. No. 4,693,117 describes a shielded tubular gauge for placement between two spaced apart fittings connected to a vessel to show the level of liquid in the vessel, including an elongated sheet of protective material slidable received in the U-shaped edges of the frame.
Jackson U.S. Pat. No. 4,345,468 describes a level sight monitor which includes a double tube sight element. The internal glass element is connected to the liquid system being monitored. The external tube is transparent plastic and provides a protective shield to the internal pipe and is spaced apart from the internal tube with “O” rings fitted, preferably flanged inserts. The annulus between the two tubes can be environmentally purged.
Gruett, U.S. Pat. No. 3,886,796 describes a gauge for indicating liquid level in a tank with a transparent plastic tube disposed between a pair of hollow end members.
GENERAL SUMMARY DISCUSSION OF INVENTION
It is an object of the present invention to provide a safety liquid level sight gauge that includes a transparent sight tube coax ally disposed between mounting blocks and concentrically within a transparent shielding tube which protects the sight tube from breakage and collects leaking contents.
It is another object of the present invention to provide a safety liquid level sight gauge with a sight tube breakage shut off system that includes; a pair of check valves positioned on both ends of the gauge within sight gauge mounting blocks, a transparent sight tube is coaxially disposed between the check valves, a two piece check valve push rod is axially disposed end to end and supported within the bore of the sight tube and extends about the length of the sight tube whereby the push rod urges both check valves to an open position allowing liquid to enter the bore of the sight tube and whereby the end to end alignment of the push rods slips when the sight tube is either cracked or broken allowing the check valves to move to a closed position.
It is another object of the present invention to provide a safety liquid level sight gauge with a leak shut off system which allows the check valves, described above, to move to a closed position when a leak occurs from the transparent sight tube or its connection with the mounting blocks, the leak shut off system includes; an interstices formed between an outer surface of a transparent sight tube and an inner surface of a concentrically placed transparent shield tube, the interstice is in communication with a diaphragm positioned at one end of an adjustable check valve activation plunger, the plunger is keyed and has a longitudinal axis perpendicularly aligned with a longitudinal axis of the check valve push rods and positioned between one end of one push rod and one check valve. The activation plunger has two positions; a normal position which allows longitudinal push rod movement to be transferred to the check valve through a moveable transfer pin, and a leak shut off position which allows the check valves to move to a closed position by aligning an aperture through the plunger with the push rod and the check valve. A spring urges the plunger to remain in the normal position by overcoming the pressure, a pressure change within the interstices cause the diaphragm to move the plunger by overcoming the biasing force of the spring and urging the plunger to move to the leak shut off position allowing the push rod and check valve to r tract into the plunger aperture thereby closing the check valves. The plunger spring force is adjustable allowing a user to adj
Egan Russell J.
Loo Dennis
Williams Hezron
LandOfFree
Safety liquid level sight gauge does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Safety liquid level sight gauge, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Safety liquid level sight gauge will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2488267