US3329787A - Temperature and level sensor with heater and heat transfer means - Google Patents

Temperature and level sensor with heater and heat transfer means Download PDF

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Publication number
US3329787A
US3329787A US476341A US47634165A US3329787A US 3329787 A US3329787 A US 3329787A US 476341 A US476341 A US 476341A US 47634165 A US47634165 A US 47634165A US 3329787 A US3329787 A US 3329787A
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US
United States
Prior art keywords
temperature
casing
heat
mercury
heater
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
US476341A
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English (en)
Inventor
Peter P Novas
Robert D Ernst
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.)
NAPOR CORP
Original Assignee
NAPOR CORP
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 NAPOR CORP filed Critical NAPOR CORP
Priority to US476341A priority Critical patent/US3329787A/en
Priority to GB13025/66A priority patent/GB1076268A/en
Priority to SE8624/66A priority patent/SE309686B/xx
Priority to DE19661523425 priority patent/DE1523425A1/de
Application granted granted Critical
Publication of US3329787A publication Critical patent/US3329787A/en
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
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/18—Switches operated by change of liquid level or of liquid density, e.g. float switch
    • H01H35/183—Switches operated by change of liquid level or of liquid density, e.g. float switch making use of a thermal switch
    • 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
    • G01F23/22—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 measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—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 measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G01F23/246—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 measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid thermal devices
    • G01F23/247—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 measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid thermal devices for discrete levels
    • G01F23/248—Constructional details; Mounting of probes

Definitions

  • a temperature responsive mercury switch which is mounted in a housing projecting into the coolant or lubricant of the machinery, and which serves to close an electrical control circuit either when the temperature of the fluid medium exceeds the normal operating temperature by a predetermined amount or when the level of the coolant or lubricant drops below that of the mercury switch.
  • a heater coil for generating a predetermined amount of heat which is greater than the heat of the fluid medium at normal operating temperature.
  • part of the coil heat in excess of the heat of the fluid medium is dissipated into the fluid medium, while the other part of the excess coil heat is directed to the mercury switch.
  • the latter increment of heat, together with the heat of the fluid medium at normal operating temperature is insufficient to close the mercury switch.
  • the total heat generated by the heater coil is directed to the mercury switch for effecting closing of the latter.
  • the electrical circuit controller is independent of any amplifying devices for providing a' signal of suflicient magnitude to activate current available signal or control devices connected in the control circuit.
  • FIGURE 1 is a side elevational view of the tempera ture and level sensor of our present invention extending through the wall of a sump or tank, a fragmentary portion of which is shown in section;
  • FIGURE 2 is a lengthwise median sectional view of the temperature and level sensor of FIGURE 1;
  • FIGURE 3 is an end elevational view of the temperature and level sensor of FIGURE 1;
  • FIGURE 4 is a transverse sectional view, taken substantially along the line 44 in FIGURE 2, looking in the direction indicated by the arrows;
  • FIGURE 5 is a schematical wiring diagram of a circuit incorporating the temperature and level sensor of our present invention.
  • the controller 10 comprises a generally tubular elongated housing 12 having a closed end 14 and an intermediate threaded portion 16.
  • the unit 10 is adapted to be threaded into the wall of a sump or tank 18 associatedwith or forming part of machinery.
  • the housing 12 is thereby arranged to project into the fluid medium (not shown), such as coolant or lubricant, within the sump 18.
  • a heater coil assembly 38 Disposed within the housing 12 adjacent the closed end 14 there is a heater coil assembly 38 which includes a core or spool 40 recessed to receive the end of casing 22, and a coil 42.
  • a pair of arcuate metal heat transfer bands 44 Arranged intermediate of the housing 12 and the casing 22 adjacent and in line with the reservoir bulb 24 are a pair of arcuate metal heat transfer bands 44 which may be fabricated of good heat conducting material, for example, of beryllium copper.
  • the bands 44 substantially center the glass casing 22 within the housing 12, and resiliently support the glass casing 22 thereby protecting it against undue vibration.
  • An insulating washer 46 is disposed at the ends of the heat transfer bands 44 adjacent the heater coil assembly 38 to prevent direct heat transfer from the heater to the bands and necessitating transfer of heat to the bands from the coil through the casing and/or fluid medium in which the sensor is positioned, and a centering washer 48 of heat insulating material is mounted at the other ends of the heat transfer bands 44.
  • Mounted in the end of the housing 12 exteriorly of the sump 18 is a terminal bushing 50 providing support for a pair of terminal prongs 52 and 54.
  • the interior of the housing 12 about the contact end of the switch and between the assembly 38 and the glass casing 22 is filled with a suitable resilient, heat insulating potting compound 56.
  • the one side of the heater coil 42 and the terminal prong 52 are interconnected at the terminal band 34, the other side of the heater coil 42 and the contact 28 are interconnected at the terminal band 36, the contact 28 is grounded to the housing 12, and the contact 30 has connection with the terminal prong 54.
  • the terminal prong 52 and the casing 12 are adapted to be connected to a source of power for actuating the heater coil 42, while the terminal prong 54 is adapted to be connected to an emergency signal or control device not shown.
  • the elements of the controller 10 are so arranged that the normal operating temperature of the fluid medium, either coolant or lubricant, in the sump 18 causes the mercury 32 to expand within the capillary tube 26 to a point adjacent the contact 28.
  • the heater coil 42 when energized generates a predetermined amount of heat which is greater than the heat of the fluid medium at normal operating temperature. Normally, part of the coil heat in excess of the heat of the fluid medium is directed to the mercury 32 to expand the same within the capillary tube 26 beyond the point corresponding to the normal operating temperature of the fluid medium to a point intermediate the contacts 28 and 30; the other part of the excess coil heat is dissipated through the housing 12 into the adjacent fluid medium.
  • the total amount of heat generated by the coil 42 is determined by the size of the coil and the amount of current applied thereto.
  • the mercury 32 is caused to expand still further within the capillary tube 26 until, in response to a predetermined temperature rise of the fluid medium, the mercury bridges the contacts 28 and 30 causing energization of the control device connected to the terminal prong 54. Also, if there should be a loss of fluid medium in the sump 18 causing the level of the fluid medium to drop below that of the unit 10, heat generated by the heater coil 42 is no longer partially dissipated through the housing 12 into the fluid medium.
  • temperature and level sensor of our present invention can be readily adjusted to accommodate numerous temperature settings and differentials for a wide range of level and temperature control applications.
  • our temperature and level sensor is capable of activating directly (through solidstate or electro-mechanical means) an unlimited variety of signal or control devices for visual, audible, electrical, mechanical and electro-mechanical indication or control.
  • a temperature and level sensor comprising, an elongated tubular casing adapted to extend into a container of fluid medium to sense the temperature and level of said medium, said casing being closed at the free end thereof Within said medium, a temperature responsive mercury switch within said casing including an elongated glass body, a reservoir in said body in communication with a capillary tube therein, mercury in said reservoir expandable in said tube, first and second spaced contacts along said tube adapted to be connected to electrical circuitry whereby predetermined temperature expansion of said mercury causes electrical connection of said contacts, heater means within and in direct contact with said casing at the free end thereof, resilient heat insulating means between said heater means and glass body, heat transfer means within said casing between said casing and glass body for creating a heat path therebetween and aligned with said reservoir, heat insulating means Within said casing between the casing and glass body and between said heater means and the adjacent end of the heat transfer means, and said heater means having such capacity that it will cause expansion of the mercury to electrically interconnect the contacts in the event the temperature of the

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
  • Level Indicators Using A Float (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Emergency Alarm Devices (AREA)
  • Thermally Actuated Switches (AREA)
US476341A 1965-08-02 1965-08-02 Temperature and level sensor with heater and heat transfer means Expired - Lifetime US3329787A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US476341A US3329787A (en) 1965-08-02 1965-08-02 Temperature and level sensor with heater and heat transfer means
GB13025/66A GB1076268A (en) 1965-08-02 1966-03-24 Temperature and liquid level sensor
SE8624/66A SE309686B (enrdf_load_stackoverflow) 1965-08-02 1966-06-23
DE19661523425 DE1523425A1 (de) 1965-08-02 1966-08-02 Temperatur- und Niveaufuehler

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US476341A US3329787A (en) 1965-08-02 1965-08-02 Temperature and level sensor with heater and heat transfer means

Publications (1)

Publication Number Publication Date
US3329787A true US3329787A (en) 1967-07-04

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ID=23891457

Family Applications (1)

Application Number Title Priority Date Filing Date
US476341A Expired - Lifetime US3329787A (en) 1965-08-02 1965-08-02 Temperature and level sensor with heater and heat transfer means

Country Status (4)

Country Link
US (1) US3329787A (enrdf_load_stackoverflow)
DE (1) DE1523425A1 (enrdf_load_stackoverflow)
GB (1) GB1076268A (enrdf_load_stackoverflow)
SE (1) SE309686B (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859645A (en) * 1973-06-04 1975-01-07 Gte Sylvania Inc Temperature compensated fluid level sensor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0474905A1 (de) * 1990-09-13 1992-03-18 VDO Adolf Schindling AG Niveauschalter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1560119A (en) * 1921-09-12 1925-11-03 Cutler Hammer Mfg Co Thermally-operated circuit controller
US2158146A (en) * 1937-09-20 1939-05-16 Vapor Car Heating Co Inc Thermostat
US2619566A (en) * 1949-08-25 1952-11-25 Charles F Mahoney Actuating apparatus responsive to change in liquid level
US3102179A (en) * 1957-08-09 1963-08-27 Hermeyer Robert Liquid contact switch

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1560119A (en) * 1921-09-12 1925-11-03 Cutler Hammer Mfg Co Thermally-operated circuit controller
US2158146A (en) * 1937-09-20 1939-05-16 Vapor Car Heating Co Inc Thermostat
US2619566A (en) * 1949-08-25 1952-11-25 Charles F Mahoney Actuating apparatus responsive to change in liquid level
US3102179A (en) * 1957-08-09 1963-08-27 Hermeyer Robert Liquid contact switch

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859645A (en) * 1973-06-04 1975-01-07 Gte Sylvania Inc Temperature compensated fluid level sensor

Also Published As

Publication number Publication date
SE309686B (enrdf_load_stackoverflow) 1969-03-31
GB1076268A (en) 1967-07-19
DE1523425A1 (de) 1969-02-20

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