Steam Main Jargon Buster

Backpressure

Is the resistance to a moving fluid. An example of this might be on a steam trap application, where 'back pressure' is the pressure just downstream of the steam trap. This forms a resistance to the trap's inlet (primary) pressure.

Baffle

A part of a shell and tube heat exchanger. It purpose is to support the tube bundles and help guide the shell side fluid across the tubes to improve the heat transfer rate.

Balanced pressure steam trap

A type of steam trap fitted with a balanced pressure thermostatic capsule element. The element is liquid filled which enables it to expand or contract to close or open the orifice in the steam trap. This type of element is capable of changing its operating temperature depending on and relative to surrounding steam pressure. The element would typically sense the upstream pressure, and be designed to operate at a fixed temperature below steam saturation temperature. This enables the element to open the orifice in the steam trap to allow cooler condensate to be discharge, while closing when hotter steam comes into contact with the element.

Ball valve

A valve which has a disc inside it which is shaped like a ball. This ball has a hole or port which controls the fluid through it. The valve can come in full bore (in essence the same port size as the pipeline serving the valve) or reduced bore (port is one size smaller than the pipework serving the valve). Ball valves can be manually operated or automated by using an actuator.

bar a

A shorthand used for absolute pressure measured in bar.

bar g

A shorthand used for gauge pressure measured in bar.

Barometric pressure

The pressure of the prevailing atmosphere.

Base exchange softening

A type of water softener which is used to treat the water going to a steam boiler (via the boiler feedtank). It is the simplest type of ion exchange and the most widely used. It consists of a resin bed (normally contained in a glass fibre reinforced plastic pressure vessel(s)) and a brine regeneration tank. The raw water is passed through the resin bed, where it is softened.

Bellows

A pipeline fitting which allows for pipe expansion and contraction.

Bend

A type of pipe fitting. It is similar to an elbow, but has a longer radius.

BG01

A UK guidance notice on the safe operation of boilers. It is a joint document by the Safety Assessment Federation and Combustion Engineering Association, produced in consultation with the UK Health and Safety Executive.

Blowdown

This is the removal of water from a boiler in order to control the quality of the water in the boiler (this to prevent; corrosion, carryover, and other issues). Blowdown can be broken down into two types. TDS (total dissolved solids) blowdown is used to remove suspended solids present in the boiler, and is normally located just over half way up the side of the boiler shell. Bottom blowdown is used to remove sludge from the bottom of the boiler. The valve is normally located at the bottom of the boiler at the opposite end from the burner. As water from the boiler is removed via these blowdown processes, it is replaced with water from the boiler feedwater tank.

Blowdown pit

A pit sunk in the ground usually outside the boiler house to receive blowdown water from the steam boilers. It is normally brick lined. It is modern practice to use a blowdown vessel now, rather than a pit.

Blowdown vessel

A vessel that takes the blowdown from the boiler. On some sites a pit may be used instead of a vessel

BMS

Building management system. A networked control system to allow central control and monitoring of many processes.

Boiler

A steam boiler is the heart of the steam system. It generates heat (normally by burning a fuel) and uses it to heat water which creates steam. Boilers can also come in different types to heat other mediums (e.g. water, oil).

Boiler burner

A fuel injection device attached to the combustion chamber which fires the boiler.

Boiler efficiency

A way of quantifying the performance of a boiler. It is expressed by; the ratio of heat energy contained in the steam produced from the boiler relative to the heat contained in the fuel required to produce it.

Boiler feed valve

A valve that automatically controls the supply of feedwater to a steam boiler.

Boiler feedwater

The water that has been chemically treated so that it is suitable for use in a steam boiler.

Boiler house

The actual building that contains the boilers and other associated equipment.

Boiler lockout

This is an automatic event triggered by the water level reaching the second low alarm in a steam boiler. The burner is locked out/off so no more heat energy is introduced into the boiler. The boiler cannot restart automatically even if the water level returns to normal. A suitably trained boiler person must reset the boiler. Lock out is designed to aid the safety of boiler.

Boiler water level control

In a steam boiler this refers to the system which controls the water level inside the boiler, and provides safety features such as low alarms and lockout control.

Boilermaker

A manufacturer of boilers.

Bottom blowdown

Bottom blowdown is used to remove sludge from the bottom of the boiler. The valve is normally located at the bottom of the boiler at the opposite end from the burner (see blowdown).

BREEAM

An acronym for the Building Research Establishment Environmental Assessment Method. BREEAM provides authoritative guidance on ways of minimising the adverse effects of buildings on the environments.

British thermal units

A traditional unit for energy. Btu is defined as the heat required to raise the temperature of 1lb of water from 59° to 60°F.

BS

British standards. Also known as BSI, British Standards Institute. It produces standards and related services.

BSA1 valve

Model number for a type of in-line stop valve manufactured by Spirax Sarco. Body is made from cast iron. It is a globe type isolation/stop valve with a bellows sealed stem (please also see globe type valve).

BSA2 valve

Model number for a type of in-line stop valve manufactured by Spirax Sarco. Body is made from SG iron. Usually used on steam (can be used on other applications subject to being suitable), it is a globe type isolation/stop valve with a bellows sealed stem (please also see globe type valve).

BSA3 valve

Model number for a type of in-line stop valve manufactured by Spirax Sarco. Body is made from cast steel. Usually used on steam (can be used on other applications subject to being suitable), it is a globe type isolation/stop valve with a bellows sealed stem (please also see globe type valve).

BSP

British Standard Pipe thread, is a family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends. BSP mates an external (male) thread with an internal (female) thread. BSP threads can be distinguished as either Parallel (denoted by the letter G) or Tapered (denoted by the letter R).

Btu

British thermal units. A traditional unit for energy. Btu is defined as the heat required to raise the temperature of 1lb of water from 59° to 60°F.

Butt weld

This is a method of welding pipework to a component such as a valve. The pipe butts up to the component rather than being inserted into a socket.

Butterfly valve

A type of valve who's name comes from the wing like structure and action of the valve disc which is arranged on the pipe diameter principle. The circular shaped disc turns about a diametrical axis within the cylindrical bore of the valve body and a quarter turn rotation of the disc opens and closes the valve. The basic simplicity of the design provides a compact and relatively low weight having few component parts. The quarter turn action offers quick opening and closing with ease of operation and the valve has good flow control characteristics. The design concept of the butterfly valve is particularly suited to large size manufacture and has found wide acceptance in oil, gas, chemical, water treatment, and process industries. They would not normally be used on steam applications.

Byworth Boilers

A boiler manufacturer established in 1968, based in Keighley in the UK.


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