| 摘要 |
A trap for particulates in a fluid flow line between a wellhead and a choke having a casing defining a chamber and having an inlet to the chamber which is connected to the wellhead and an outlet from the chamber which is connected to the choke. A filter at the outlet retains particulates entrained in the fluid flowing through in the chamber, which may be opened to allow accumulated particulates to be cleared from the chamber. The inlet and outlet boss, which are attached to the inlet/outlet end respectively are screw-threaded to the casing, and are connected or connectable to a inlet/outlet flange which is attached to an inlet/outlet pipe. The outlet flange provides access means when not attached to the boss. The filter element is screw-threaded to the outlet flange so that removal of the outlet flange from the casing also removes the filter element from the casing to allow its replacement. Supporting means to support the weight of the outlet flange and the attached filter element when separated from the boss is provided by a gantry rail attached to the casing so that a distal end thereof extends above and beyond the outlet end of the casing, and a traveller on the rail which is connected to the outlet flange. The filter element comprises a perforated tube attached at one end to the outlet flange and closed at its distal end and covered between its ends with a tubular screen. The casing, bosses, flanges and any bolts used are made of high tensile steel with no welded joints in the trap. Installation of a second trap whereby one trap may be operational while the other is closed of to allow it to be emptied may be in parallel between the wellhead and the choke with each trap connected to a different choke. The trap has means of indicating differential pressure between the inlet and outlet end of the chamber. The fluid at the wellhead is at high pressure is induced to flow in the flow line by the choke being opened to some extent. The pressure at the wellhead is such as to enable fluid to flow through the partially opened choke at supersonic speeds and the choke is operated so that the fluid flows from the wellhead from the choke at subsonic speeds.
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