US3751616A - Float switches - Google Patents

Float switches Download PDF

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Publication number
US3751616A
US3751616A US00267221A US3751616DA US3751616A US 3751616 A US3751616 A US 3751616A US 00267221 A US00267221 A US 00267221A US 3751616D A US3751616D A US 3751616DA US 3751616 A US3751616 A US 3751616A
Authority
US
United States
Prior art keywords
sensing element
magnet
tube
mounting plate
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00267221A
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English (en)
Inventor
R Innes
N West
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TRIST CONTROLS Ltd RONALD
Meggitt UK Ltd
Original Assignee
TRIST CONTROLS Ltd RONALD
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TRIST CONTROLS Ltd RONALD filed Critical TRIST CONTROLS Ltd RONALD
Application granted granted Critical
Publication of US3751616A publication Critical patent/US3751616A/en
Assigned to BESTOBELL (UK) LIMITED reassignment BESTOBELL (UK) LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BESTOBELL MOBREY LIMITED A BRITISH COMPANY
Assigned to BESTOBELL MOBREY LIMITED reassignment BESTOBELL MOBREY LIMITED CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE JAN. 1, 1975. Assignors: RONALD TRIST CONTROLS LIMITED
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H36/00—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding
    • H01H36/02—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding actuated by movement of a float carrying a magnet
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/30—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats
    • G01F23/32—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats using rotatable arms or other pivotable transmission elements
    • G01F23/38—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats using rotatable arms or other pivotable transmission elements using magnetically actuated indicating means

Definitions

  • An electrical switch assembly for measuring liquid levels or flow, has a mounting plate which is arranged to [21 1 Appl' 267221 be fitted to a container wall to seal an aperture through the wall, a tube which is made of a non-magnetic mate- [30] Foreign Application Priority Data rial, which extends through and is sealed in a bore in July 1971 Great Britain 34 250/71 the plate, and which has its end on the wet side of the plate sealed; a sensing element which is arranged to be 52 U.S. Cl 200/84 c mved by the quid miner and a magnet 51 Int. Cl.
  • the invention is concerned with electrical switch assemblies for measuring liquid levels or flow, and which is mounted in a wall of a boiler or other liquid container.
  • the assembly has a sensing element which is arranged to be moved by the liquid and a magnet which is connected to and moves with the sensing element, the magnet operating magnetically responsive switch contacts through a non magnetic wall which separates the switch contacts from the interior of the container.
  • the sensing element may be, for example, a float which is moved upon change in liquid level or a paddle which is moved by flow of the liquid.
  • the assembly is mounted at an aperture in the container wall by means of a mounting plate having a peripheral edge which overlaps the container wall around the aperture and is bolted to it with an interposed gasket.
  • the sensing element and magnet are then pivotally mounted on the wet side of the mounting plate and the switch contacts are mounted on the dry side of the plate the plate being of a non-magnetic material so that the magnet can influence the switch contacts through the plate.
  • the mounting plate is responsible for maintaining a liquid seal with the container wall, it must be of comparatively large and robust construction. Since it is made of a non-magnetic material, such as stainless steel, which is expensive, each contributes appreciably to the overall price ofthe assembly. Difficulties may also arise with regard to the sensitivity of the response of the switch contacts throughthe mounting plate.
  • an electricalswitch assembly for measuring liquid levels or flow, comprises a mounting plate which is arranged to be fixed to a container wall to seal an aperture through the container wall; a'tube which is made of-a non-magnetic material, which extends through andis sealed in'a bore in the plate, and which has its endon the wet side of the plate sealed; a sensing element which is arranged to be moved by the liquid in the container and a magnet which, with the sensing element, is pivotally mounted on the wet side of the mounting plate; a magnetically responsive switch contact unit within the tube and responsive'to ,movemen-tof the magnet upon movement of the sensing element; and a terminal housingmounted on thedry side-of the mounting plate and incorporating terminals connected to the reed switch contact unit.
  • the mounting plate may be made of a cheap material such as mild steel, although it may be made of a non-corrosive material such as stainless steel if the liquid is such that it is desirable to present a non-corrosive material completely on the wet side of the assembly.
  • the assembly may be extremely sensitive because the tube may be comparatively thin walled, compared with the thickness of the mounting plate, and consequently. the magnet may move in comparatively close proximity to the, switch contact unit. This construction also has a good tolerance to vibration.
  • the switch unit of the assembly may be a reed switch, or, alternatively, a micro-switch the arm of which cooperates with the magnet. With either of these types of switches the assembly is very suitable for use with failsafe" switching systems.
  • the tube which may be made of stainless steel extends closely through a bore in the mounting plate and is expanded at say two annular rings to very tight sealing engagement with the wall of the bore.
  • a glandless seal connection between the tube and the mounting plate is thus provided by normal metalworking techniques.
  • the sensing element and magnet may be mounted independently on the mounting plate, but are preferably mounted on the sealed end of the tube. The necessary special relationship between the moving magnet and the switch contact unit is thus assured.
  • FIG. 1 is a partially sectioned side elevation of the assembly
  • FIG. 2 is a view on arrow II in FIG. 1, the terminal cover having been removed.
  • This example has a mounting plate 1 which is arranged to be mounted overlapping the edge of an aperture in a vertical side wall of a liquid container.
  • a stainless steel tube 2 extends through a bore in the plate and is sealed in it by means of two annular expansion rings 3.
  • the end of the tube on the wet side of the plate is sealed by means of a welded plug 4.
  • the tube extends by over half its length from the wet side of the mounting plate andextends just fromthe dry side of the mounting plate into a terminal housing 5 which is screwed and sealed by a gasket 6 to the dry side of the mounting plate.
  • the tube contains substantially centrally a sealed reed switch contact unit 7.
  • One of the reeds of the unit extends from the unit towards the wet side end of the tube and lead wires 8 extend from the unit through the dry side end of the tube into the terminal' housing 5 where they are connected in a terminal block 9 having connections for outside wires. These outside wires which are not shown would leave the terminal housing through the opening 10, which in this case is shown threaded for the attachment of a conduit for containing the wires.
  • the wet side end of the tube supports the bracket 11 which carries, o'na horizontal pivot 12, afloat l3 and a stainless steel encapsulated bar magnet 14. 1 1 i I FIG. 2'shows in detail the arrangement within the terminal housing 5, the cover 15 having been removed.
  • the float moves upwards and downwards with the liquid level, the operative end of the magnet moving downwards and upwards respectively beneath the end of the tube and below the end of the projecting reed.
  • the reed switch is relieved of the influence of the magnet and it adopts its equilibrium position, and as the float falls the magnet rises and the reed switch contact unit responds.
  • this switch assembly is very simply modified/The mounting plate might be mounted horizontally in a conduit wall, and the float 13 would be replaced by a paddle. This arrangement would produce a very sensitive flow switch.
  • An electrical switch assembly for measuring liquid levels or flow, comprising a mounting plate which is arranged to be fixed to a container wall to seal an aperture through said container wall; a tube which is made of a non-magnetic material, which extends through and is sealed in a bore in said plate, which is expanded at two annular rings into tight sealing engagement with the wall of said bore, and which has its end on the wet side of said plate sealed; a sensing element which is arranged to be moved by the liquid in said container and a magnet which, with said sensing element, is pivotally mounted on said wet side of said mounting plate; a magnetically responsive switch contact unit within said tube and responsive to movement of said magnet upon movement of said sensing element; and a terminal housing mounted on the dry side of said mounting plate and incorporating terminals connected to said switch contact unit.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Level Indicators Using A Float (AREA)
  • Measuring Volume Flow (AREA)
US00267221A 1971-07-21 1972-06-28 Float switches Expired - Lifetime US3751616A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3425071A GB1388845A (en) 1971-07-21 1971-07-21 Magnet switch for liquid containers

Publications (1)

Publication Number Publication Date
US3751616A true US3751616A (en) 1973-08-07

Family

ID=10363297

Family Applications (1)

Application Number Title Priority Date Filing Date
US00267221A Expired - Lifetime US3751616A (en) 1971-07-21 1972-06-28 Float switches

Country Status (6)

Country Link
US (1) US3751616A (it)
DE (2) DE7226377U (it)
FR (1) FR2146224B1 (it)
GB (1) GB1388845A (it)
IT (1) IT961473B (it)
NL (1) NL7209248A (it)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258238A (en) * 1978-09-06 1981-03-24 Sunvic Regler Gmbh Liquid level signal transmitter
US4305285A (en) * 1979-06-07 1981-12-15 Nissan Motor Co., Ltd. Liquid level detecting and warning device
US4356729A (en) * 1979-06-07 1982-11-02 Nissan Motor Co., Ltd. Fluid level detector
US5374790A (en) * 1993-02-05 1994-12-20 Rochester Gauges, Inc. Liquid level switch assembly
US6380499B1 (en) 1999-05-21 2002-04-30 Breed Automotive Technology, Inc. Float sensor employing reed switch
US20040200278A1 (en) * 2003-04-10 2004-10-14 Neil Gansebom Side-mountable fluid level sensor
US20150083557A1 (en) * 2013-09-26 2015-03-26 New Widetech Industries Co., Ltd. Water tank with a magnetic reed switch
US20170250041A1 (en) * 2016-02-26 2017-08-31 S.J. Electro Systems, Inc. Magnetically actuated switch

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2744901C2 (de) * 1977-10-06 1985-06-13 Turbo-Werk Messtechnik GmbH, 5000 Köln Wächter für den Durchfluß oder Füllstand von Medien
US4513185A (en) * 1982-01-19 1985-04-23 Lucas Industries Float operated electrical switch assembly
DE3203110A1 (de) * 1982-01-30 1983-08-18 Sunvic Regler Gmbh, 5650 Solingen Elektrischer messumformer fuer fuellstand
GB9603489D0 (en) * 1996-02-20 1996-04-17 Elfab Ltd Fluid flow detection device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2857492A (en) * 1956-02-01 1958-10-21 Edmund A Kathe Liquid level control switch
US2887546A (en) * 1957-06-26 1959-05-19 W E Anderson Inc High pressure, explosion proof, fluid flow controlled electrical switch
US2927176A (en) * 1955-01-06 1960-03-01 Phillips Aviat Co Magnetic switch mechanism
US3322917A (en) * 1966-01-25 1967-05-30 Black Sivalls & Bryson Inc Float switch
US3359385A (en) * 1966-06-09 1967-12-19 Caterpillar Tractor Co Flow sensing device
US3421124A (en) * 1967-03-17 1969-01-07 Joseph V Kidd Detector switch

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2927176A (en) * 1955-01-06 1960-03-01 Phillips Aviat Co Magnetic switch mechanism
US2857492A (en) * 1956-02-01 1958-10-21 Edmund A Kathe Liquid level control switch
US2887546A (en) * 1957-06-26 1959-05-19 W E Anderson Inc High pressure, explosion proof, fluid flow controlled electrical switch
US3322917A (en) * 1966-01-25 1967-05-30 Black Sivalls & Bryson Inc Float switch
US3359385A (en) * 1966-06-09 1967-12-19 Caterpillar Tractor Co Flow sensing device
US3421124A (en) * 1967-03-17 1969-01-07 Joseph V Kidd Detector switch

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258238A (en) * 1978-09-06 1981-03-24 Sunvic Regler Gmbh Liquid level signal transmitter
US4305285A (en) * 1979-06-07 1981-12-15 Nissan Motor Co., Ltd. Liquid level detecting and warning device
US4356729A (en) * 1979-06-07 1982-11-02 Nissan Motor Co., Ltd. Fluid level detector
US5374790A (en) * 1993-02-05 1994-12-20 Rochester Gauges, Inc. Liquid level switch assembly
US6380499B1 (en) 1999-05-21 2002-04-30 Breed Automotive Technology, Inc. Float sensor employing reed switch
US20040200278A1 (en) * 2003-04-10 2004-10-14 Neil Gansebom Side-mountable fluid level sensor
US6892573B2 (en) 2003-04-10 2005-05-17 Key Safety Systems, Inc. Side-mountable fluid level sensor
US20150083557A1 (en) * 2013-09-26 2015-03-26 New Widetech Industries Co., Ltd. Water tank with a magnetic reed switch
US20170250041A1 (en) * 2016-02-26 2017-08-31 S.J. Electro Systems, Inc. Magnetically actuated switch
US10141141B2 (en) * 2016-02-26 2018-11-27 S. J. Electro Systems, Inc. Magnetically actuated switch

Also Published As

Publication number Publication date
FR2146224A1 (it) 1973-03-02
NL7209248A (it) 1973-01-23
IT961473B (it) 1973-12-10
FR2146224B1 (it) 1976-01-16
DE7226377U (de) 1975-09-04
GB1388845A (en) 1975-03-26
DE2234861A1 (de) 1973-02-01

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Legal Events

Date Code Title Description
AS Assignment

Owner name: BESTOBELL (UK) LIMITED, BESTOBELL HOUSE, 16 BATH R

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BESTOBELL MOBREY LIMITED A BRITISH COMPANY;REEL/FRAME:004118/0616

Effective date: 19830217

Owner name: BESTOBELL MOBREY LIMITED

Free format text: CHANGE OF NAME;ASSIGNOR:RONALD TRIST CONTROLS LIMITED;REEL/FRAME:004118/0618

Effective date: 19750101