US4465088A — Construction of low water level sensing device fo…

Claim 1

Independent Claim 267 words

In a pressurized heating system having water in a boiler and a low water level sensor and safety cut-off device associated with the boiler and operable to shut off the system when the water in the boiler drops below a predetermined level, said low water sensor device comprising: (a) a housing having a cavity; (b) means mounting said housing on the vessel such that a substantial portion of said housing, having the cavity therein, is external of the vessel; (c) a sensor in said cavity responsive to the liquid level therein and operably associated with the heating system to shut off the same when the liquid level in the boiler drops below a predetermined level; (d) a passageway in said housing having an open inlet end immersed in the water during normal operation of the boiler, said passageway providing fluid flow communication between the interior of the vessel and said cavity, the inlet to such passage being at a lower vertical elevation than the level of the water in the cavity at which the sensor is operative to shut off the system in a low water condition; (e) valved passage means in the portion of said housing disposed exteriorly of the vessel for injecting a gas into said cavity to pressurize the cavity above the normal pressure therein; and (f) normally open valved passage means in the portion of the housing located exteriorly of the vessel and connected to some higher point in the system such as an accumulator providing means for releasing the gas from said cavity and equalizing pressure between the cavity and the boiler.

Claim 2

Dependent Claim 267 words

In a pressurized heating system having water in a boiler and a low water level sensor and safety cut-off device associated with the boiler and operable to shut off the system when the water in the boiler drops below a predetermined level, said low water sensor device comprising: (a) a housing having a cavity; (b) means mounting said housing on the vessel such that a substantial portion of said housing, having the cavity therein, is external of the vessel; (c) a sensor in said cavity responsive to the liquid level therein and operably associated with the heating system to shut off the same when the liquid level in the boiler drops below a predetermined level; (d) a passageway in said housing having an open inlet end immersed in the water during normal operation of the boiler, said passageway providing fluid flow communication between the interior of the vessel and said cavity, the inlet to such passage being at a lower vertical elevation than the level of the water in the cavity at which the sensor is operative to shut off the system in a low water condition; (e) valved passage means in the portion of said housing disposed exteriorly of the vessel for injecting a gas into said cavity to pressurize the cavity above the normal pressure therein; and (f) normally open valved passage means in the portion of the housing located exteriorly of the vessel and connected to some higher point in the system such as an accumulator providing means for releasing the gas from said cavity and equalizing pressure between the cavity and the boiler.

Claim 3

Dependent Claim 42 words

A system as defined in claim 1 wherein said gas release means in spaced a selected distance downwardly from an upper end of said cavity and wherein the inlet end of the passageway is located adjacent an opposite end of the cavity.

Claim 4

Dependent Claim 25 words

A system as defined in claim 2 wherein said sensor is an elongate electrode suspended from the housing at the upper end of the cavity.

Claim 5

Dependent Claim 34 words

A system as defined in claim 3 wherein said electrode is suspended from an insulator that projects into the cavity and wherein the gas release means is at a lower elevation than the insulator.

Claim 6

Dependent Claim 23 words

A system as defined in claim 4 wherein said housing is threaded into a threaded bung in the upper wall of the boiler.

Claim 7

Dependent Claim 24 words

A system as defined in claim 5 wherein said housing includes a lower portion that projects into the boiler beyond the upper wall thereof.

Claim 8

Dependent Claim 199 words

A low water sensing device for use in a pressure hot water heating system to operate a safety cut-off when water in the boiler drops below a predetermined level, said device comprising a housing having an elongate cavity therein open at one end and closed at the opposite end; an elongate electrode suspended from an insulator mounted in said housing at said opposite end of the cavity, the axial length of said electrode within said cavity being less than that of the cavity whereby the end of the electrode is offset upwardly from the open lower end of the cavity; a first valved air inlet passage means through said housing into said cavity adjacent said opposite end thereof; a second air release passage means through said housing spaced a predetermined distance from said opposite end of the cavity in a direction toward said one end; and means located between said second air release passage means and said one end of the cavity for sealingly mounting said housing in an opening in the upper wall of the boiler of the pressure hot water heating system with the open end thereof in fluid flow communication with the interior of the boiler.

Claim 9

Dependent Claim 199 words

A low water sensing device for use in a pressure hot water heating system to operate a safety cut-off when water in the boiler drops below a predetermined level, said device comprising a housing having an elongate cavity therein open at one end and closed at the opposite end; an elongate electrode suspended from an insulator mounted in said housing at said opposite end of the cavity, the axial length of said electrode within said cavity being less than that of the cavity whereby the end of the electrode is offset upwardly from the open lower end of the cavity; a first valved air inlet passage means through said housing into said cavity adjacent said opposite end thereof; a second air release passage means through said housing spaced a predetermined distance from said opposite end of the cavity in a direction toward said one end; and means located between said second air release passage means and said one end of the cavity for sealingly mounting said housing in an opening in the upper wall of the boiler of the pressure hot water heating system with the open end thereof in fluid flow communication with the interior of the boiler.

Claim 10

Dependent Claim 14 words

A device as defined in claim 7 wherein said insulator projects into said cavity.

Claim 11

Dependent Claim 26 words

A device as defined in claim 7 wherein said housing comprises an upper, an intermediate and a lower portion and wherein said portions are detachably interconnected.

Claim 12

Dependent Claim 21 words

A device as defined in claim 9 wherein said boiler mounting means is located on said intermediate portion of said housing.

Claim 13

Dependent Claim 29 words

A device as defined in claim 10 wherein one end of the lower portion of said housing is clampingly disposed between said upper and intermediate portions of said housing.

Claim 14

Dependent Claim 26 words

A device as defined in claim 10 wherein each of said first and second air passage means are located in the upper portion of said housing.

Claim 15

Independent Claim 152 words

A method of testing operability of the sensor of a low water cut-off in a pressure hot water heating system having an accumulator therein without draining down the system comprising: (a) locating the sensor in a cavity communicating with the interior of the boiler via a passageway extending beyond the sensor, said cavity being at least partially filled with water during operation of the boiler; (b) injecting gas from a position exteriorly of the boiler into said cavity to pressurize the same to an extent so as to drive water in the cavity to a level so as to simulate a low water condition and thereby determine whether or not the sensor is operable; and (c) releasing only a portion of the injected gas from a position spaced downwardly from the upper end of the cavity to thereby maintain a gas bubble of selected size at the uppermost end of the cavity.

Claim 16

Independent Claim 152 words

A method of testing operability of the sensor of a low water cut-off in a pressure hot water heating system having an accumulator therein without draining down the system comprising: (a) locating the sensor in a cavity communicating with the interior of the boiler via a passageway extending beyond the sensor, said cavity being at least partially filled with water during operation of the boiler; (b) injecting gas from a position exteriorly of the boiler into said cavity to pressurize the same to an extent so as to drive water in the cavity to a level so as to simulate a low water condition and thereby determine whether or not the sensor is operable; and (c) releasing only a portion of the injected gas from a position spaced downwardly from the upper end of the cavity to thereby maintain a gas bubble of selected size at the uppermost end of the cavity.

Claim 17

Dependent Claim 249 words

In a hot water heating system having water in a boiler and a low water level sensor and safety cut-off device associated with the boiler and operable to shut off the system when the water in the boiler drops below a predetermined level, said low water sensor device comprising: (a) a housing having a cavity therein; (b) means mounting said housing on an upper wall of the vessel; (c) a sensor comprising an elongate electrode suspended from an insulator that projects into the upper end of said cavity and responsive to the liquid level therein, said sensor being operably associated with the heating system to shut off the same when the liquid level in the boiler drops below a predetermined level; (d) a passageway in said housing extending downwardly from said sensor into the interior of the vessel and having an open inlet end immersed in the water during normal operation of the boiler, said passageway providing fluid flow communication between the interior of the vessel and said cavity, the inlet to such passage being at a lower vertical elevation than a lower terminal end of the sensor; (e) valved passage means in said housing disposed exteriorly of the vessel for injecting a gas into said cavity to pressurize the cavity above the normal pressure therein; and (f) means, located exteriorly of the vessel, for releasing the gas from said cavity, said gas release means being at a lower elevation than the insulator from which the probe is suspended.

Claim 18

Dependent Claim 249 words

In a hot water heating system having water in a boiler and a low water level sensor and safety cut-off device associated with the boiler and operable to shut off the system when the water in the boiler drops below a predetermined level, said low water sensor device comprising: (a) a housing having a cavity therein; (b) means mounting said housing on an upper wall of the vessel; (c) a sensor comprising an elongate electrode suspended from an insulator that projects into the upper end of said cavity and responsive to the liquid level therein, said sensor being operably associated with the heating system to shut off the same when the liquid level in the boiler drops below a predetermined level; (d) a passageway in said housing extending downwardly from said sensor into the interior of the vessel and having an open inlet end immersed in the water during normal operation of the boiler, said passageway providing fluid flow communication between the interior of the vessel and said cavity, the inlet to such passage being at a lower vertical elevation than a lower terminal end of the sensor; (e) valved passage means in said housing disposed exteriorly of the vessel for injecting a gas into said cavity to pressurize the cavity above the normal pressure therein; and (f) means, located exteriorly of the vessel, for releasing the gas from said cavity, said gas release means being at a lower elevation than the insulator from which the probe is suspended.

Claim 19

Dependent Claim 24 words

A system as defined in claim 14 wherein said housing includes a lower portion that projects into the boiler beyond the upper wall thereof.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-08-14	1988-02-13	1988-08-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-08-14	1992-02-13	1992-08-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-08-14	1996-02-13	1996-08-14	$7700.00	Window Closed / Lapsed

Construction of low water level sensing device for hot water boiler

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