The following article lists some simple, informative tips that will help you have a better experience with Piping Material Specification Terms.
Compact Gate Valve
Compact gate valves are used for economic reasons. They are cheaper and weighs lesser. Lesser weight in a piping system means fewer supports and therefore, savings. It is used for small size gate valves up to 1-½” although the standards supports its use up to 2”. This is because most projects have socketwelds only up to 1- ½” NPS. The reference for these valves is API 602.
Full Port(Bore) vs. Reduced Port (Bore) vs. Standard Port(Bore)
The full port valve has an inlet and an outlet size equal to the ball opening size. In contrast, a reduced port has a bigger inlet tapering towards the smaller ball opening. The outlet tapers toward a bigger exit. Standard port is actually another name for reduced port.
Reducers
Reducers may either be concentric or eccentric. However, for small reducers, most often than not, they are concentric because they are made of forged material like A105. With Caltex specifications, small reducers are not distinguished (as to whether they are concentric or eccentric), which can be confusing.
Piston Lift
This type of check valve uses the piston in the form of a cylinder, with its lower end shaped to form a seating face. The cylindrical part fits into the shell. The piston must be long enough to ensure that it is well guided over the distance of its travel. Likewise, piston-type check valves shall have an integral or separate guide of sufficient length to ensure effective guidance over the full length of the piston travel.
Tanged Insert
A type of gasket used as a substitute for asbestos.
SC, BC
Check valves do not have bonnets, instead covers are used. SC stands for Screwed Cover while BC means Bolted Cover. Screwed Cover is usually used for low pressure service, instrument air and water. Bolted Covers can be used for higher pressure service.
Bonnet
Bonnet is a valve body closure component that contains an opening for the stem. Attachment of bonnet to the body shall be either of the following types:
Bolted bonnet (BB) - A valve construction in which the bonnet is bolted in the body. A mating flange between the body and bonnet shall be installed. This flange shall be of a suitable shape to provide adequate strength. The joint between the body and bonnet shall be of a type that confines the gasket.
Screwed bonnet (SB) - A valve construction in which the body and the bonnet are attached using by a threaded end. There are two types namely:
Threaded-in bonnet - a bonnet that is threaded into the body.
Threaded-over bonnet - a bonnet into which the body is threaded.
Screwed bonnet is mainly used for instrument air, potable water lines and very low pressure service such as CL125 and CL150. Some projects require seal welding for this type of valve construction.
Union bonnet (UB) - A valve bonnet that is fastened to the valve body by means of a union nut. Union bonnet valve construction may be used for very low pressure service.
Welded bonnet (WB) - A valve construction wherein the bonnet is welded to the body. This type of bonnet is rarely used but is applicable for very toxic fluid service (Type M). Maintenance or replacement of the unit is difficult for the welding is uneasy to remove.
Pressure seal bonnet (PSB) - A bonnet closure assembly in which internal fluid pressure force on the bonnet increases the compressive loading on the sealing gasket. This type of assembly is very expensive and usually used for very high pressure services (over 900 psi).
Gland
A part of a valve that provides compression on the packing to prevent leakage.
OS&Y (Outside Screw and Yoke)
A valve design where in the packing is between the stem threads and the valve body. Yoke is a part of a valve assembly used to position the stem nut to mount the valve actuator.
ISS (Inside Screw and Stem)
This assembly is of two types namely:
Inside screw non-rising stem - A type of gate valve design where in the disc rises on the threaded part of the stem instead of the stem rising through the bonnet. The stem does not rise or descend as the stem is turned.
Inside screw rising stem - A type of gate valve or globe valve design where in the stem has both rotary and axial motions and rises as the stem is turned. The stem threads are between the stem packing and closure member.
Stem - a valve component to which motion is impaired outside the valve assembly to move the closure member inside the valve.
Seats
There are two seats in a valve: the disc seat and the body seat. The disc seat is softer and removable. The body seat is usually harder than the disc. All disc seats can be removed unlike body seats.
There's a lot to understand about Piping Material Specification Terms. We were able to provide you with some of the facts above, but there is still plenty more to write about in subsequent articles.
