Safety control valve

{
  "publication_number": "US3631893A",
  "country": "US",
  "kind": "A",
  "title": "Safety control valve",
  "abstract": "A safety control valve to be disposed on a tank for loading and unloading liquefied gas therefrom. The safety control valve includes a valve body having a valve seat at an end thereof within the tank and a main valve plug cooperating therewith. A pilot valve plug slidably carries the main valve plug. An operator actuates the pilot valve plug to bleed pressure from the tank and permit opening of the main valve plug. The main valve plug will close if there is excess flow above a predetermined value, due, for example, to a break in the pipeline downstream of the valve.",
  "claims": [
    "1. A safety control valve comprising a unitary valve body adapted to be secured to a tank for pressurized fluid, said valve body having a single chamber defining a flow passage therethrough, valve seat means formed on the upper end of said valve body, support means in said valve body, pilot valve means slidable in said support means, said pilot valve means including a center stem portion, a main valve slidable on said center stem portion of said pilot valve means and cooperating with said valve seat means for closing flow through said flow passage, there being a pilot passage through the main valve between the exterior of the pilot valve means and the interior of the main valve, first spring means between the support means and main valve for biasing the main valve toward open position, second spring means between the support means and pilot valve means for biasing the pilot valve means toward the main valve to close the pilot passage, said spring means both being on the same side with respect to the valve seat means, and cam means in said valve body for actuating said pilot valve means to permit equalization of pressure on opposite sides of said main valve, whereby the first spring means will bias the main valve open, and in the event of a downstream problem and pressure drop, the pressurized fluid will cause the main valve to seat against the valve seat means, said cam means including a shaft carrying a cam member thereon, and spring means for biasing the shaft to enable closure of the pilot valve means by the second spring means, said valve body having an opening therein of sufficient size to receive the shaft and cam member, wherebY the cam member can be readily removed from the valve body through said opening for repair or replacement.",
    "2. A safety control valve comprising a unitary valve body adapted to be secured to a tank for pressure fluid, said valve body having a single chamber defining a flow passage therethrough, an upper end portion of said valve body being secured to said tank, valve seat means on said end portion of said valve body, a pilot valve slidable in said valve body and having an upstanding center portion, a main valve slidable on said center portion of said pilot valve and cooperating with said valve seat means for closing flow through said flow passage, there being a pilot passage defined between said center portion of the pilot valve and the main valve, said pilot valve including a head portion seating against said main valve for closing the pilot passage, first spring means about the center portion between the pilot valve and main valve for biasing the main valve toward open position, second spring means between the valve body and pilot valve for biasing the pilot valve to move the head portion against said main valve to close the pilot passage, said spring means both being on the same side with respect to the valve seat means, and cam means in said valve body actuable from outside the valve body for actuating said pilot valve, whereby the cam means moves the pilot valve to compress the second spring means and open the pilot passage to permit equalization of pressure on the upstream and downstream surfaces of the main valve, and upon such equalization of pressure, the first biasing means will open the main valve, said main valve being closed when the pressure drop across it overcomes the force of the first biasing means, said cam means including a shaft carrying a cam member thereon, said valve body having an opening therein of sufficient size to receive the shaft and cam member, whereby the cam member can be readily removed from the valve body through said opening for repair or replacement."
  ],
  "cpc": [
    "F16K 17/168",
    "F16K 31/52408",
    "F17C 13/12",
    "F17C 2205/0329",
    "F17C 2205/0332",
    "F17C 2205/0382",
    "F17C 2205/0394",
    "F17C 2221/035",
    "F17C 2223/0153",
    "F17C 2223/033",
    "F17C 2250/0636",
    "F17C 2260/022",
    "Y10T 137/7869",
    "Y10T 137/86944",
    "Y10T 137/87394",
    "Y10T 137/87515"
  ],
  "ipc": [
    "F16K 17/168",
    "F17C 13/12"
  ],
  "assignees": [
    "Fisher Controls International LLC"
  ],
  "inventors": [
    "Weadell L Seaman",
    "William A Etter"
  ],
  "filing_date": "1969-05-02",
  "publication_date": "1972-01-04",
  "grant_date": "1972-01-04",
  "priority_date": "1969-05-02",
  "application_number": "US-3631893D-A",
  "family_id": "25232896",
  "cited_by_count": 64,
  "citations": [
    "US299669A",
    "US2765801A",
    "US1028682A",
    "US2834377A",
    "US3095899A",
    "US3032067A",
    "US3469605A"
  ]
}