Flowmeter

{
  "publication_number": "US3583220A",
  "country": "US",
  "kind": "A",
  "title": "Flowmeter",
  "abstract": "A fluid flow-measuring system, especially for fluids of high viscosity in which a pair of rotors is driven by the flow of the fluid passing from the inlet to the outlet of the meter, in which the rotary velocity of one rotor is transmitted to an integrating meter, and this one rotor is also connected to a servomotor, and in which any difference in pressure at the inlet and the outlet is detected by a pressure difference-detecting assembly, and the thus detected pressure difference is converted into an electric signal which is transmitted to the servomotor so as to rotate the latter and the rotor connected thereto in such a manner to reduce the pressure difference to substantially zero. The pressure difference-detecting assembly comprises a chamber partitioned by a diaphragm into two compartments, respectively connected by a pair of conduits to the region of the inlet and the outlet of the flow meter, the conduits and compartments being filled with a fluid of low viscosity and the ends of the conduits at the region of the inlet and the outlet being closed by flexible diaphragms.",
  "claims": [
    "1. A fluid flow-metering system, especially for metering fluid of high viscosity, comprising, in combination, wall means defining a chamber having an inlet and an outlet; a pair of meshing gear rotors located in said chamber to be rotated by said fluid to be measured and passing from said inlet to said outlet; a heating jacket surrounding said chamber for heating said fluid of high viscosity passing therethrough to reduce the viscosity thereof; pressure-sensing means for sensing the pressure difference between said chamber upstream and downstream of said pair of rotors; a casing spaced from said chamber and the heating jacket surrounding the same; electric servomotor means connected to one of said rotors for rotating the same, said servomotor means being located in said casing; a tube extending between said wall means forming said chamber and said casing; a shaft extending through said tube and connecting said one rotor with said servo motor means; means in said casing and connected to said shaft for indicating the amount of fluid passing through said metering system in dependence on the revolutions of said rotor; cooling means for cooling said tube to thus prevent transmission of heat imparted to said chamber by said servomotor and said indicating means; and means cooperating with said pressure-sensing means and said servomotor for producing an electrical signal depending on the magnitude of the difference of pressure sensed by said sensing means and for changing by said electrical signAl the rotational speed of said servomotor means and that of said one rotor connected thereto in such a manner so as to reduce the pressure difference substantially to zero.",
    "2. A fluid flow metering system as defined in claim 1, wherein said pressure-sensing means comprises a second chamber, a flexible diaphragm extending transversely through said second chamber and dividing the latter into a pair of discrete compartments, a pair of conduits each having a first and a second end, the first end of one of said conduits communicating with one of said compartments and the second end thereof ending in said first-mentioned chamber upstream of said rotors, and the first end of the other of said conduits communicating with the other of said compartments and the second end thereof ending in said first chamber downstream of said rotors, a fluid of low viscosity filling said conduits and said compartments, and a pair of flexible diaphragm means extending in said first chamber over said second ends of said conduits for separating said low viscosity fluid in said conduits from said high viscosity fluid to be measured, whereby any difference in the pressure of the fluid to be measured will be transmitted through said diaphragm means and the low viscosity fluid in said conduits to said flexible diaphragm in said second chamber to flex said diaphragm in the one or the opposite direction, and wherein said means for producing an electrical signal depending on the magnitude of the pressure difference comprises a differential transformer having a core connected to said diaphragm for moving therewith and a differential transformer coil surrounding said core and connected to said electrical servomotor means."
  ],
  "cpc": [
    "G01F 3/10"
  ],
  "assignees": [
    "OVAL ENG CO LTD"
  ],
  "filing_date": "1968-06-20",
  "publication_date": "1971-06-08",
  "grant_date": "1971-06-08",
  "priority_date": "1968-06-20",
  "application_number": "US-3583220D-A",
  "family_id": "24969021",
  "citations": [
    "GB758094A",
    "US1451064A",
    "US1518279A"
  ]
}