A small-flow valve connected to a fluid process vessel or line for the purpose of bleeding off small quantities of contained fluid.

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A valve used to drain off material that has separated from a fluid or gas stream, or one used to empty a process line, vessel, or storage tank.


A process of removing air from fluid lines or pipes.


A manually operated valve in the oil line for the purpose of completely turning on or shutting off the oil supply to the burner.


The point, on the fore and aft line of a vessel at which the upward force of buoyancy acts. It is measured from amidships either forward or aft.


The process of transferring cargo from one vesel to another to reduce the draft of the first vessel. Done to allow a vessel to enter a port with limited depth or to help free a grounded vessel.


A cylindrical vessel designed to deliver cement or water into a well which otherwise might cave in if fluid was poured from the top.


A lead placed on the bottom to indicate movement of a vessel. At anchor the lead line is usually secured to the rail with a little slack and if the ship drags anchor, the line tends forward. A drift lead is also used to indicate when a vessel coming to anchor is dead in the water or when it is moving astern. A drift lead can be used to indicate current if a ship is dead in the water.


Ungraduated portion of line connected with a current pole used in taking current observations The stray line is usually about 100 feet long and permits the pole to acquire the velocity of the current at some distance from the disturbed waters in the immediate vicinity of the observing vessel before the current velocity is read from the graduated portion of the current line.


A pipe or duct, usually controlled by valve or damper, for conveying a fluid around an element of a system.


A method of solving the various problems involving course, distance, difference of latitude, difference of longitude, and departure. The various methods are collectively spoken of as the sailings. Plane sailing considers the earth as a plane. Traverse sailing applies the principles of plane sailing to determine the equivalent course and distance made good by a craft following a track consisting of a series of rhumb lines. Any of the sailings which considers the spherical or spheroidal shape of the earth is called spherical sailing. Middlelatitude sailing is a method of converting departure into difference of longitude, or vice versa, by assuming that such a course is steered at the middle or mean latitude; if the course is 090° or 270° true, it is called parallel sailing. Mercator sailing applies when the various elements are considered in their relation on a Mercator chart. Meridian sailing is used when the course is 000° or 180° true. Rhumb-line sailing is used when a rhumb line is involved; great- circle sailing when a great circle track is involved. Composite sailing is a modification of great circle sailing used when it is desired to limit the highest latitude. The expression current sailing is occasionally used to refer to the process of allowing for current in determining the predicted course made good, or of determining the effect of a current on the direction of motion of a vessel.

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