Measuring and testing – Fluid pressure gauge – Mounting and connection
Reexamination Certificate
1999-10-22
2001-08-28
Oen, William (Department: 2855)
Measuring and testing
Fluid pressure gauge
Mounting and connection
Reexamination Certificate
active
06279403
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to differential pressure sensors, and more particularly to a differential pressure triggering device deprived of a traversing actuating tappet.
BACKGROUND
Differential pressure sensors usually have a tappet passing through a housing wall of the sensor to actuate an external switch device. Such a configuration is necessarily open to pressure leaks and yields to inaccurate readings and/or results, especially in high pressure applications such as for example in ventilation ducts.
Known in the art is U.S. Pat. No. 5,024,294 (Van Fossen et al.), which shows a differential pressure transducer having a diaphragm subjected to different pressures from each side. A rod is attached to the diaphragm, the rod supporting a magnet moving inside the transducer's housing as a function of the measured pressure differential. The rod is suspended at one end by a tension spring, the opposite end of the rod being attached to the diaphragm. The displacement of the rod caused by the flexion of the diaphragm is measured by means of a Hall effect sensor mounted in the transducer's housing.
Also known in the art is U.S. Pat. No. 3,967,504 (Akeley), which shows a differential pressure sensor having a spring subjected to compression when the pressure in a high pressure line exceeds the pressure in a low pressure line.
Also known in the art is U.S. Pat. No. 3,831,588 (Rindner), which shows a pressure measuring device producing an electric signal proportional to the pressure. The device is housed in a chamber having a flexible diaphragm to transmit external pressure to the sensor.
Also known in the art is U.S. Pat. No. 5,817,943 (Welles, II et al.), which shows a pressure sensor having a structure for generating a magnetic force to balance forces on opposite sides of a flexible diaphragm centered within a pressure chamber in which a fluid under pressure is introduced on a side of the diaphragm.
Also known in the art is U.S. Pat. No. 5,303,595 (Shoji et al.), which shows a pressure sensor based on a magnetostriction effect.
Also known in the art is U.S. Pat. No. 5,355,714 (Suzuki et al.) which shows a pressure sensor using a pressure responsive magnetic film to vary the inductance of a coil. The diaphragm is arranged to displace depending on a pressure differential, thereby changing the inductance of the coil.
Also known in the art are U.S. Pat. No. 3,575,054 (Glista); U.S. Pat. No. 3,590,638 (Anastasia); U.S. Pat. No. 4,336,567 (Anastasia); U.S. Pat. No. 4,373,385 (Boutteville et al.); U.S. Pat. No. 4,453,412 (Nakane); U.S. Pat. No. 4,475,405 (Corpron et al.); U.S. Pat. No. 4,487,074 (Herden); U.S. Pat. No. 4,671,116 (Glennon et al.); U.S. Pat. No. 4,716,492 (Charboneau et al.); U.S. Pat. No. 4,876,893 (Kato et al.); U.S. Pat. No. 5,068,503 (Sladky); U.S. Pat. No. 5,219,041 (Greve); U.S. Pat. No. 5,315,878 (Birenheide); U.S. Pat. No. 5,437,241 (Rosenberg et al.); U.S. Pat. No. 5,760,310 (Rud, Jr. et al.); U.S. Pat. No. 5,874,680 (Moore); U.S. Pat. No. 5,880,373 (Barton); U.S. Pat. No. 5,889,212 (Guthrie et al.); and U.S. Pat. No. 5,908,990 (Cummings) which all show various types of pressure sensors illustrating the state of the art.
SUMMARY
An object of the invention is to provide a differential pressure triggering device deprived of an actuating tappet crossing the device's housing wall.
A subsidiary object of the invention is to provide such a differential pressure triggering device that is simple in construction, thus highly cost-competitive, yet is highly reliable and efficient.
Another subsidiary object of the invention is to provide such a differential pressure triggering device which provides accurate readings and triggering functions even if the device is subjected to high positive or negative pressures.
According to the present invention, there is provided a differential pressure triggering device, comprising a housing having first and second adjacent inner chambers, and first and second pressure inlets communicating respectively with the first and second inner chambers. A pressure deflectable member extends between the inner chambers, the deflectable member being responsive to a pressure differential between the inner chambers. A first magnetic member is positioned inside the first inner chamber and is attached to the deflectable member so that a deflection of the deflectable member displaces the first magnetic member along a predetermined displacement course inside the first inner chamber. A trigger unit is mounted outside the housing alongside the first inner chamber, the trigger unit including an actuator and a switch device responsive to a motion of the actuator for producing a triggering action. A second magnetic member is attached to the actuator in magnetic interactive mobile arrangement with the first magnetic member so that a displacement of the first magnetic member along the displacement course, resulting from a deflection of the deflectable member, causes a corresponding displacement of the second magnetic member, thereby driving the actuator which operates the switch device.
REFERENCES:
patent: 3575054 (1971-04-01), Glista
patent: 3590638 (1971-07-01), Anastasia
patent: 3831588 (1974-08-01), Rindner
patent: 3967504 (1976-07-01), Akeley
patent: 4249780 (1981-02-01), Mehren
patent: 4336567 (1982-06-01), Anastasia
patent: 4373385 (1983-02-01), Boutteville et al.
patent: 4453412 (1984-06-01), Nakane
patent: 4475405 (1984-10-01), Corpron et al.
patent: 4487074 (1984-12-01), Herden
patent: 4671116 (1987-06-01), Glennon et al.
patent: 4716492 (1987-12-01), Charboneau et al.
patent: 4876893 (1989-10-01), Kato et al.
patent: 5024294 (1991-06-01), Van Fossen et al.
patent: 5068503 (1991-11-01), Sladky
patent: 5219041 (1993-06-01), Greve
patent: 5303595 (1994-04-01), Shoji et al.
patent: 5315878 (1994-05-01), Birenheide
patent: 5355714 (1994-10-01), Suzuki et al.
patent: 5437241 (1995-08-01), Rosenberg et al.
patent: 5760310 (1998-06-01), Rud, Jr. et al.
patent: 5817943 (1998-10-01), Welles, II et al.
patent: 5874680 (1999-02-01), Moore
patent: 5880373 (1999-03-01), Barton
patent: 5889212 (1999-03-01), Guthrie et al.
patent: 5908990 (1999-06-01), Cummings
Henlex Inc.
Merchant & Gould P.C.
Oen William
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