US3356803A - Pressure switch having means for increasing the stroke of a bellows pressure sensing element - Google Patents

Pressure switch having means for increasing the stroke of a bellows pressure sensing element Download PDF

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Publication number
US3356803A
US3356803A US528910A US52891066A US3356803A US 3356803 A US3356803 A US 3356803A US 528910 A US528910 A US 528910A US 52891066 A US52891066 A US 52891066A US 3356803 A US3356803 A US 3356803A
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United States
Prior art keywords
pressure
bellows
chamber
fluid
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
US528910A
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English (en)
Inventor
Jr Melvin W Redmond
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.)
Applied Biosystems Inc
Original Assignee
Perkin Elmer 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 Perkin Elmer Corp filed Critical Perkin Elmer Corp
Priority to US528910A priority Critical patent/US3356803A/en
Priority to DE19671665353 priority patent/DE1665353A1/de
Priority to CH214267A priority patent/CH457589A/de
Priority to GB8009/67A priority patent/GB1177252A/en
Priority to FR8822A priority patent/FR1512016A/fr
Application granted granted Critical
Publication of US3356803A publication Critical patent/US3356803A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/32—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by bellows

Definitions

  • a pressure actuated switching arrangement including an electro-deposited bellows and means for providing a continuous flow path for a fluid through a chamber formed by the bellows.
  • An electrical switching device is positioned with respect to the bellows for actuation thereby when the fluid in the bellows chamber attains a preselected pressure.
  • a static superatmospheric bias pressure is applied to an outer surface of the bellows.
  • This invention relates to absolute or differential pressure actuated switches.
  • a pressure actuated switching arrangement is employed for effecting a desired control function when the pressure exerted by a fluid in the apparatus attains a desired level.
  • T he control function may comprise the interruption of fluid flow.
  • Such a switching arrangement generally includes a pressure sensing means exposed to the fluid and electrical contacts adapted to be actuated by the sensing means.
  • Another object is to provide a pressure actuated switching arrangement which is adapted for relatively clean operation.
  • a further object of the invention is to provide a pressure actuated switching arrangement which is adapted for repeated operation at a desired pressure level with relatively high precision.
  • a pressure actuated switching arrangement includes a flexible pressure sensing means having a first surface thereof forming a flexible wall portion of a pressure chamber. Means provide a continuous flow path for a fluid through the chamber. Electrical switching means are positioned with respect, to a second surface of the flexible wall and are adaptedfor actuation upon the attainment of a preselected chamber pressure.
  • the flexible sensing means is generally cylindrically shaped and is adapted for both longitudinal expansion and contraction. A static bias pressure is applied to a second surface of the flexible chamber wall; With this'arrangement, the pressure chamber may advantageously be quickly flushed between successive sample investigations and the possibility of contamination from different samples is greatly reduced. In addition, re-
  • FIGURE 1 is a perspective view, partly cut away, of the pressure actuated switching arrangement of the present invention
  • FIGURE 2 is an elevation view, partly cut away and partly in section, of the pressure actuated switching arrangement of FIGURE 1;
  • FIGURE 3 is a schematic of an apparatus utilizing the pressure actuated switching arrangement of FIGURES 1 and 2.
  • a pressure actuated switching arrangement as illustrated comprises a pressure sensing means and an electrical switching means.
  • the pressure sensing means is shown to comprise a bellows, indicated generally as 12, having a flexible wall formed by integral disc segments 16 and integral segments 17.
  • the bellows is generally cylindrical and tubular shaped and includes a first end-closure member 18.
  • This closure member may be an integral part of the bellows or alternatively, a disc which is hermetically sealed to the bellows at this end to form a rigid, flat surface.
  • An inner surface 19 of the flexible wall, the member 18, and a boss 20 extending into the bellows define a pressure chamber indicated generally by 21.
  • the bellows 12 is hermetically sealed to and secured to a base member 22 by any conventional sealing process such as a soft solder seal indicated as 23.
  • the boss 20, which is shown to extend from and comprise an integral segment of the base member 22 provides an-inlet port 24 and an outlet port 25 for the pressure chamber. This arrangement reduces the internal volume of the sample area.
  • An inlet duct 26 and an outlet duct 27 provide a fluid communication path between these ports and a fluid input tube 28 and an ouput tube 29.
  • the inlet duct 26 may be adapted as indicated, by reference numeral 30, to accept a threaded connector of the type which provides a pressure seal.
  • the outlet duct is arranged similarly.
  • the electrical switching means comprises a switch, indicated generally as 30, having a contact 32 mounted on a resilient swinger arm 33 and a contact 34 mounted I on a rigid stationary arm 35.
  • the arms 33 and 35 are spaced apart and supported by a block of insulating material 36.
  • A-support bracket 7 supports the switch 30 with relation to the bellows for actuation thereby.
  • the switch 30 also includes a pair of terminals 71 and 38 which are electrically coupled to hermetically sealed feed-through insulating terminals 39 and 40 by wires 41.
  • acontact plate 42 which is mounted on the end member 18 by any convenient method, such as soldering will contact swinger arm 33 and cause the contacts 32 and 34 to make electrical contact. Contraction of the bellows will cause these contacts to separate.
  • Various arrangements of normally'open and normally closed contacts may be employed in this electrical switching means.
  • a static bias pressure is established on the outer surface 43 of the bellows wall by hermetically sealing the atmosphere surrounding the bellows, indicated generally as 44, and by maintaining this atmosphere at a desired pressure level.
  • an enclosure 45 is hermetically sealed to the base member 22 by any conventional means. This enclosure 45 thereby provides the sealed atmosphere surrounding the bellows.
  • This atmosphere is pressurized by introducing a fluid through a tubulation, not shown, which is later tippedoff in a known manner.
  • the tubulation tip off is indicated 3 as 46.
  • the atmosphere 44 within the enclosure 45 may be evacuated.
  • a difference in fluid pressure between the pressures of the chamber.21 and the atmosphere 44 exerts a force on the bellows wall and causes it to elongate or compress longitudinally from a zero differential pressure position with respect to the base member 22, indicated as Y
  • the bias pressure of the atmosphere 44 is established at a pressure level, P midway between an initial relatively lower pressure level, P and a final relatively higher pressure level, P to be measured in the pressure chamber 21.
  • P the bellows will be compressed to the position (Y D
  • the chamber pressure increases the bellows elongates from this initial position through Y and finally to (Y +D when the chamber pressure attains its final level.
  • a sample having elements which are to be detected is transported by a carrier fluid of the apparatus through the duct 26 into the chamber 21 and from the chamber 21 via the duct 27 to other parts of the instrument.
  • the pressure of the carrier fluid causes the bellows to extend from the level (Y D
  • the bellows will elongate from (Y D to (Y -l-D causing the contact plate 42 to actuate the switch 30 and generally initiate a desired control function.
  • This preselected level will be established by the composition and associated characteristics of the bellows along with the magnitude of the fluid pressures in the atmosphere surrounding the bellows.
  • a cleansing fluid Upon completion of an analysis of a sample, a cleansing fluid will be introduced into the pressure chamber 21 via the tube 28 and the inlet duct 26.
  • the cleansing fluid maintains not only clean piping but also advantageously cleans the interior of the pressure chamber.
  • An arrangement of this type in addition to providing relatively clean operation is particularly suited for reliable repeatability of actuation of the switch 30 within a relatively narrow deviation range from some nominal pressure.
  • P of two atmospheres of fluid pressure when it is desired to actuate the switch 30 at a final chamber pressure, P of two atmospheres of fluid pressure, then one forin of the bellows illustrated may operate with a bias atmosphere having a pressure P within the enclosure 45 of one and one half atmospheres.
  • a bellows movement resulting from a pressure change of one atmosphere from an initial chamber pressure P of one atmosphere to a final pressure P of two atmospheres will actuate the switch.
  • a particular form of bellows which may be employed with the arrangement of FIGURES 1 and 2 comprises an electro-deposited bellows which is conveniently formed in a known manner from nickel or nickel cobalt alloy.
  • a bellows of this type which may be used in an extension or compression through many operations while maintaining its operational characteristics provides nearly double the allowable bellows stroke and this substantially increases the resolution of the level of actuation by a factor of two. Repeatable accuracy of actuation with a pressure switch employing this form of bellows has been held to an error of .l% or less of the actuation pressure.
  • FIGURE 3 an apparatus is shown utilizing the pressure switch arrangement of the present invention and illustrating its operation in the control of the flow of a carrier fluid.
  • the apparatus includes the pressure switch arrangement of FIGURES l and 2, indicated in FIGURE 3 generally by a block bearing the reference numeral 50.
  • the switch arrangement 50 is coupled to a source of carrier fluid and sample 52 by the inlet tubing 28 and to a flow valve 56 by the outlet tubing 29.
  • the flow valve 56 is further coupled by tubing 58 to a utility apparatus 60.
  • a positive terminal of a Car source of electrical potential 62 is coupled to a feedthrough terminal 39 while a negative terminal of the source of electrical potential 62 is coupled to the feedthrough terminal 4% via a series circuit path including a common ground connection and an electrical control element of the flow valve 56 such as a solenoid winding, not illustrated.
  • the valve 56 is connected in series in the fluid line. As the pressure attains the preselected level, for example, the bellows will expand and the contact plate 42 will cause the switch 30 to close and actuate the solenoid to thereby actuate the valve and interrupt fluid flow.
  • bias atmosphere 44 may be coupled to a source of varying pressure.
  • the switch 30 will then be actuated at some preselected differential varying pressure level.
  • a pressure actuated switching arrangement which is particularly adapted for repeatedly operating at an absolute pressure within a narrow deviation from a preselected pressure level and which includes a pressure chamber flow-through fluid path thereby providing a facility for quickly removing contaminants.
  • An analytical instrument comprising:
  • means including an inlet duct and an outlet duct for conveying a fluid in a continuous flow path under pressure through said pressure chamber, and
  • a pressure actuated switching device comprising:
  • a closure member positioned at a first end of the said bellows for traversing a longitudinal path upon elongation or compression of said bellows
  • an electrical switching means having a pair of contact surfaces and positioned with respect to said closure member for actuation of said contacts by said closure member
  • means including a second closure member positioned at a second end of said bellows having an inlet and an outlet port for said bellows for conveying a fluid under pressure in a continuous flow path through said bellows.
  • a pressure actuated switching device comprising:
  • an electrical switch having a pair of contacts and positioned with respect to said bellows for actuation of said contacts by said closure member
  • said latter end member having a fluid inlet port and fluid outlet port
  • inlet and outlet ducts communicating with said inlet and outlet ports for conveying a fluid in a continuous flow path through a pressure chamber formed by said flexible wall and closure member

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Diaphragms And Bellows (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Measuring Fluid Pressure (AREA)
US528910A 1966-02-21 1966-02-21 Pressure switch having means for increasing the stroke of a bellows pressure sensing element Expired - Lifetime US3356803A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US528910A US3356803A (en) 1966-02-21 1966-02-21 Pressure switch having means for increasing the stroke of a bellows pressure sensing element
DE19671665353 DE1665353A1 (de) 1966-02-21 1967-02-11 Druckbetaetigte Schalteranordnung
CH214267A CH457589A (de) 1966-02-21 1967-02-13 Druckbetätigte Schaltanordnung
GB8009/67A GB1177252A (en) 1966-02-21 1967-02-20 Pressure Actuated Electric Switch
FR8822A FR1512016A (fr) 1966-02-21 1967-02-21 Dispositif de connexion à commande par pression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US528910A US3356803A (en) 1966-02-21 1966-02-21 Pressure switch having means for increasing the stroke of a bellows pressure sensing element

Publications (1)

Publication Number Publication Date
US3356803A true US3356803A (en) 1967-12-05

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Family Applications (1)

Application Number Title Priority Date Filing Date
US528910A Expired - Lifetime US3356803A (en) 1966-02-21 1966-02-21 Pressure switch having means for increasing the stroke of a bellows pressure sensing element

Country Status (5)

Country Link
US (1) US3356803A (de)
CH (1) CH457589A (de)
DE (1) DE1665353A1 (de)
FR (1) FR1512016A (de)
GB (1) GB1177252A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177035A2 (de) 1984-10-02 1986-04-09 Omron Tateisi Electronics Co. Druckempfindlicher Schalter
US5531109A (en) * 1992-10-07 1996-07-02 Tsagas; Nicolaos Indicator of the air pressure in the pneumatic tires of a vehicle based on a capacitive coupling

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1205010A (en) * 1914-04-27 1916-11-14 Carl E Pearson Ignition apparatus.
US2471838A (en) * 1945-05-24 1949-05-31 Cook Electric Co Pressure switch
US2567519A (en) * 1948-02-27 1951-09-11 Livingston Ralph Pressure monitoring device
GB668488A (en) * 1949-01-25 1952-03-19 Aerocessoires Simmonds Improvements relating to pressure-gauges
US2697764A (en) * 1950-06-17 1954-12-21 Burgua Corp Pressure-responsive switch
US2715339A (en) * 1950-08-09 1955-08-16 Socony Mobil Oil Co Inc Absolute micromanometer
US3111565A (en) * 1960-08-20 1963-11-19 Eckerfeld Alfred Electrical snap-action switch
US3250872A (en) * 1963-10-07 1966-05-10 Westport Dev & Mfg Company Inc Pressure switch with temperature setting of base pressures

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1205010A (en) * 1914-04-27 1916-11-14 Carl E Pearson Ignition apparatus.
US2471838A (en) * 1945-05-24 1949-05-31 Cook Electric Co Pressure switch
US2567519A (en) * 1948-02-27 1951-09-11 Livingston Ralph Pressure monitoring device
GB668488A (en) * 1949-01-25 1952-03-19 Aerocessoires Simmonds Improvements relating to pressure-gauges
US2697764A (en) * 1950-06-17 1954-12-21 Burgua Corp Pressure-responsive switch
US2715339A (en) * 1950-08-09 1955-08-16 Socony Mobil Oil Co Inc Absolute micromanometer
US3111565A (en) * 1960-08-20 1963-11-19 Eckerfeld Alfred Electrical snap-action switch
US3250872A (en) * 1963-10-07 1966-05-10 Westport Dev & Mfg Company Inc Pressure switch with temperature setting of base pressures

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177035A2 (de) 1984-10-02 1986-04-09 Omron Tateisi Electronics Co. Druckempfindlicher Schalter
EP0177035A3 (en) * 1984-10-02 1987-05-27 Omron Tateisi Electronics Co. Pressure sensitive switch
US4851627A (en) * 1984-10-02 1989-07-25 Omron Tateisi Electronics Co. Compact pressure sensitive switch for use in detecting fluid pressure changes
US5531109A (en) * 1992-10-07 1996-07-02 Tsagas; Nicolaos Indicator of the air pressure in the pneumatic tires of a vehicle based on a capacitive coupling

Also Published As

Publication number Publication date
FR1512016A (fr) 1968-02-02
CH457589A (de) 1968-06-15
GB1177252A (en) 1970-01-07
DE1665353A1 (de) 1971-09-16

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