A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z-
-A-
AGITATOR
Device used for agitation of a product inside a vessel.
ALLOY
An intentional combination of two or more substances, which at least one is metal and exhibits metallic properties. It can be either a mixture of two types of crystalline structures or a solid solution.
API MANWAY
Manway designed per American Petroleum Institute standards.
-B-
BAFFLE
Primarily used in vessels with an agitator. Commonly used to increase the amount of agitation or mixing, and also to limit the amount of vortex. Can also be used inside HTS for directing flow.
Related: HTS, Agitator
BASE PLATE
Flat plate attached to the base of the vessel support that supports the weight of the vessel on the mounting surface.
BLIND FLANGE
A flange without a hole; used to cap off nozzles not connected to other piping.
BOLTED MANWAY
Manway designed with mechanical fasteners for closing. Requires tools for opening
-C-
CIRCUMFERENTIAL SEAM
Weld seam around the circumference of the vessel
CLEARANCE UNDER VESSEL
Distance from the lowest point on the vessel (not including legs) to the surface nearest the vessel.
CONVENTIONAL HTS (OPEN JACKET)
Heat transfer product flows around the vessel without specific direction. May contain baffles for better coverage. This type of jacket usually require the vessel to be significantly thicker than if a dimpled or half pipe HTS were to be used.
Related: Heat Transfer Surface, Dimpled Jacket, Half Pipe HTS
COUPLING
Used to attach a pipe with a threaded end to another threaded end pipe or to the vessel.
COLUMN
Vessel designed to have specific regions, usually long and thin in shape.
CROWN RADIUS
See: Dish Radius
-D-
DATA PLATE
Plate mounted on every vessel constructed. Gives information about the manufacturer, year manufactured, pressures, temperatures, and other information related to the vessel. ASME Code requires the manufacturer, serial number, year built, and the applicable 'U' or 'R' Stamp.
Related: U-Stamp, R-Stamp
DESIGN PRESSURE
The pressure designed for the vessel. This is greater than the operating temperature by an amount to provide a safety factor.
Related: Design Temperature, MDMT, MAWP, Operating Pressure, Operating Temperature
DESIGN TEMPERATURE
The temperature designed for the vessel. This is greater than the operating pressure by an amount to provide a safety factor.
Related: Design Pressure, MDMT, MAWP, Operating Pressure, Operating Temperature
DIMPLED JACKET HTS
Heat transfer surface consisting of many pre-formed dimples attached by plug welds to the vessel exterior. Heat transfer material flows through the cavities formed by the dimples. This is a very efficient and cost effective method of HTS. Dimpled jackets are usually used in low-pressure applications.
Related: Heat Transfer Surface
DIP PIPE
A nozzle typically used for sampling or gathering data about the product inside the vessel. Usually mounted to another nozzle with a blind flange and a pipe through the blind flange into the vessel. Dip pipes can be mounted horizontally or vertically, with guides, and with wear plates.
Related: Blind Flange
DISH RADIUS
The spherical radius at the center part of the head. Abbreviated as "DR"
Related: Head, Knuckle Radius
-E-
ELECTROPOLISHING
Refers to a process whereby the surface is removed through the process of "Anodic dissolution in a suitable electrolyte under an imposed current potential".
-F-
FERRULE
A nozzle made for sanitary and low pressure applications. A ferrule contains an inset gasket surface, and is designed to work with clamps instead of bolting.
FINISHED INSIDE DEPTH (FID)
Vertical distance measured from the edge of the head to the inside top center of the head. Abbreviated as FID.
FINISHED OUTSIDE DEPTH (FOD)
Vertical distance measured from the edge of the head to the outside top center of the head. Abbreviated as FOD.
-G-
GUSSET
Plate or bracket designed to improve strength.
-H-
HALF PIPE HTS
Heat transfer surface consisting of a pipe, cut longitudinally in half, or pre-formed to 180° segments and wrapped around the exterior of the vessel. Can be used in either high or low-pressure applications.
Related: Heat Transfer Surface, Pre-Formed Tubular
HEAD
The end closure to a vessel
HEAT TRANSFER SURFACE (HTS)
Generic terminology for providing a vessel or tank with a means of temperature control. Can be used for heating, cooling, or regulation. Commonly used for steam, water, glycol, oil, or other gas, vapor, or liquid methods of heating or cooling.
-I-
ID (INSIDE DIAMETER)
Diameter of the vessel measured from the interior of the vessel surfaces. This dimension does not include the material thickness.
INSULATION RINGS
Rings designed to hold an external insulation.
INTERNAL PIPE COIL
A pipe or tube formed as a heat transfer surface and located inside a tank or vessel. The coils can be in a helical, spiral or serpentine shape.
Related: Heat Transfer Surface
-J-
JACKET
See Heat Transfer Surface, Dimpled Jacket HTS
-K-
KNUCKLE RADIUS
The curved transition from the dish radius to the vessel straight side, commonly accepted as Inside Knuckle Radius. Abbreviated as "KR"
Related: Dish Radius
-L-
LAP JOINT FLANGE
A flange similar to a slip on flange except that it fits loose on the end of a stub end.
Related: Stub End
LIFTING LUGS
Specifically designed lugs whose purpose is only for lifting and moving the vessel.
LONGITUDINAL SEAM
Weld seam parallel to the centerline of the vessel
-M-
MANWAY
Any opening on a vessel designed as an entryway for people.
MANWAY DAVIT
A device used to hold the manway cover when the manway is open.
MAWP (MAXIMUM ALLOWABLE WORKING PRESSURE)
Maximum permissible pressure at the top of the vessel during normal operating position at a specific temperature, which is usually the design temperature. MAWP is stamped on the vessel data plate when calculated.
Related: Data Plate, Design Pressure, Operating Pressure
MDMT (MINIMUM DESIGN METAL TEMPERATURE)
The lowest temperature designed for the vessel.
-N-
NOZZLE
An opening in a vessel usually consisting of a pipe or tube attached by welding, with an end designed for attachment to piping or other objects.
-O-
OD (OUTSIDE DIAMETER)
Diameter of the vessel measured from the exterior of the vessel surfaces. This dimension does include the material thickness.
OPERATING PRESSURE
The pressure at the top of the vessel at which it normally operates. The Operating Pressure shall be lower than the MAWP, design pressure, or the set pressure of any pressure-relieving device.
Related: MAWP
OPERATING TEMPERATURE
The temperature that will be maintained in the metal of the part of the vessel being considered for the specified operation of the vessel.
Related: MDMT
-P-
PAD FLANGE
Flange mounted directly to the vessel without use of pipe or tube extension. Pad flanges usually are studded for connecting to flanged piping. Pad flanges may contain a raised gasket surface. Also known as a studding flange.
PRE-FORMED TUBULAR
Similar to half-pipe, pre-formed tubular consists of several tubes cold-formed from sheet or plate. Can be used in low-pressure applications.
Related: Heat Transfer Surface, Half Pipe HTS
PRESSURE VESSEL
Vessel designed to operate under pressure at a specific temperature.
POISON PAD
A pad formed to the shape of the vessel used to separate two dissimilar metals.
PROCESSOR
Vessel designed to be used in a process.
-Q-
QUICK OPENING MANWAY
Manway designed with wing nuts for opening and closing. Can be opened without tools.
-R-
R-STAMP
A stamp on the vessel data plate indicating that repairs to an existing vessel have been made in accordance with the National Board of Boiler and Pressure Vessel Code.
Related: U-Stamp, Data Plate
RADIOGRAPHY
A non-destructive method of internal examination in which metal or other objects are exposed to a beam of x-ray or gamma radiation. Differences in thickness, density or absorption, caused by internal discontinuities, are apparent in the shadow image either on a fluorescent screen or on photographic film placed behind the object.
REACTIVE METAL
A metal that readily combines with oxygen at elevated temperatures to form very stable oxides, for example, titanium, zirconium, and beryllium. Reactive metals may also become embrittled by the interstitial absorption of oxygen, hydrogen, and nitrogen..
Related: Titanium, Zirconium
REACTOR
Vessel designed for chemical reactions. Reactors usually have internal and/or external heat transfer surfaces in conjunction with agitation.
Related: Heat Transfer Surface, Agitator
REINFORCEMENT PAD
A sheet or plate formed to the shape of the vessel around a nozzle or lug for extra strength.
-S-
SADDLE
A support made from plate to support horizontal vessels.
SANITARY MANWAY
Manway designed for sanitary systems.
SHELL
The cylindrical portion of the vessel.
SIGHT GLASS
Nozzle used for viewing the inside of a vessel while the vessel is in service.
SKIRT
Cylindrical support made of plate to support very large diameter and/or thin walled vertical vessels.
SLIP ON FLANGE
A flange containing a hub that slips over the end of a pipe and is attached with two fillet welds at the end of a pipe.
STRAIGHT FLANGE
Distance from the edge of a head to the beginning of the knuckle radius.
Related: Tangent Line, Head, Knuckle Radius
STRAIGHT SIDE
Distance of the entire shell from head to shell welds or may include the straight flanges of the heads
Related: Shell, Straight Flange, Head
STUB END
A pipe with a flat plate surface on the end for retaining a lap joint flange. The flat plate serves as the gasket seating surface (raised face).
Related: Lap Joint Flange
SUPPORT LEGS
Means of support for the vessel. Can be fabricated out of pipe, plate, structural beam, or bar. Usually attached on the lowest section of vessel and heads.
SUPPORT LUGS
Means of support for the vessel. Can be fabricated out of pipe, plate, structural beam, or bar. Usually attached near the midpoint of vessel.
-T-
TANGENT LINE
Theoretical line where the straight side of the vessel meets the knuckle radius. Also where the knuckle radius meets the dish radius is called the dished tangent point.
Related: Head, Dish Radius, Knuckle Radius
TENSILE STRENGTH
The maximum load per unit of original cross sectional area obtained before rupture of a tensile specimen.
Related: Yield Strength
THERMOWELL
Device used to measure the internal temperature of the vessel.
TITANIUM
See Reactive Metal
TONGUE AND GROOVE MANWAY
Manway with flanges that contain a tongue and groove gasket surface.
-U-
U-STAMP
A stamp on the vessel data plate indicating that a vessel has been built in accordance with the requirements of ASME Section VIII and that the vessel has been inspected and approved by a third party inspector employed by an ASME accredited inspection agency.
Related: R-Stamp, Data Plate
-V-
VACUUM RINGS
Rings made of bar, plate, or angle, designed to improve a vessel’s resistance to collapse from external pressure during operation.
VORTEX BREAKER
Plates at the outlet pipe, usually in the shape of a cross, to prevent the product from creating a vortex as it exits the vessel.
-W-
WELD LINE
Weld seam used as a reference for dimensioning.
WELD NECK FLANGE
A flange containing a neck for the purpose of welding to a pipe.
WELD PAD
See Reinforcement Pad
-X-
X-RAY
See Radiography
-Y-
YIELD STRENGTH
The stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals.
Related: Tensile Strength
-Z-
ZIRCONIUM
See Reactive Metal