Vacuum breakers, Air vents, liquid drainers expansions joints are necessary ancillaries to make your pipework function correctly.
Air vents
Air Vents are generally referred to as such in steam applications, they can be thermostatic, balanced pressure or float designs each of which has certain features and benefits depending on the particular application or installation. They operate automatically venting air from steam process or pipelines. Materials of construction can be brass, or stainless steel in sizes 15mm – 25mm. It is ideal to remove air from steam lines as air reduces the temperature of the steam space, inhibits heat transfer and is a major factor of internal pipework corrosion. Naturally they are installed at the high point of the process or pipeline. Air vents air eliminators used on liquid service in industrial applications are usually the float type. Removing air from liquid services minimises the internal corrosion (air aids corrosion). Without air the fluid dynamics improves. Always review the air vents suitability / capacity before installation.
For petrochemical applications, the pressed stainless steel body like the 11AV air vent type are more entrenched in the market over the cast float types. The pressed stainless gives effective corrosion resistance over that of a casting. Body materials are standard 304L which is cost effective but in some applications like ozone you are more likely to use 316 stainless steel. These units are normally 3/4 inlet and 1/2 outlet NPT.
Combination Air Vent – Vacuum Breakers
Combination Air vent and Vacuum Breakers are an effective and economical way to handle both venting and releasing vacuum in the one unit. It saves on costs requiring only one unit not the usual 2 and saves on installation and associated pipework. These small bore units have a number of applications from general tank service, pipework, solar installs and in hot water, light hydrocarbons and potable water service.
Vacuum Breakers
Vacuum breakers are used in both steam and liquid pipelines. In steam applications they are used to good effect at times of system shutdown when sub-atmospheric pressures may be experienced within steam pipes and apparatus. Strategically placed, they will allow condensate to gravitate down to the drain / trap points. By allowing the complete removal of condensate from any steam system, fear of water-hammer will be removed at the next system start-up. Typically they are stainless steel in 10mm or 15mm size. In liquid pipelines they have application with pumping / filling / drainage operations. Materials of construction can be thermoplastic, iron, steel and stainless steel. We also have super duplex vacuum breakers for desalination plants. Size ranges are from 15mm to 250mm in threaded and flanged connections.
Steam and hot condensate applications require units that are specifically designed for this service. Due to plant and on-site personnel safety we strongly suggest that plumbing type units or units with soft seats are not used for these applications. Soft seat units also have a comparatively short lifespan requiring frequent changeouts.
Air release Valves
Air release valves are usually termed as such in Waterworks or sewage applications. Due to their larger sizes up to 600mm are a float design. They have the ability to pass huge volumes of air / gas during the filling, draining or operation of liquid piping systems for water / wastewater services and are available in materials of thermoplastic, iron, steel, Stainless steel, Bronze and Super Duplex. Also available is the combination Air release and vacuum breaker unit i.e. incorporating 2 functions into the one valve. This can be convenient in some pipelines but NOT all as isolating the unit removes both pipeline operations. This can be detrimental in some systems hence some prefer to have both an Air release valve and a vacuum breaker that they can isolate independently.
Wastewater / Sewage lines contain higher amounts of undissolved air and gases due to decomposition of materials and they have specific air release valve designs for this application. Removing air from liquid pipelines increases the system efficiencies process wise and gives energy consumption savings. Extreme cases of air locked pipes can completely bind the system, contribute to noise and water-hammer, pipe/ valve/ pump breakages, pipe corrosion, erratic control valve operation, sensors and meters.
Liquid Drainers
Liquid drainers came into being with the growth of the oil and gas industry. Transportation and distribution of large volumes of oil and gas required the removal of liquid (usually water / condensation) from the system. Initially manual devices were used however automatic designs removed operator error and increased the efficiency and safety. This also minimized any product loss. Most units will also handle removing small amounts of residual operational contaminants ie wax, powder and scale. Some are sealed for life in the smaller sizes while some of the larger units used on oil lines are repairable. Liquid drainers are predominantly float types and available in iron, steel and stainless steel in sizes from 15mm to 50mm threaded connections.
Individual data sheets are under update if required please refer your local sales office.
A budget liquid drainer is also available for compressors, small air systems and separators. Aluminum body, float type PN16 rated and only available in 1/2 (DN15) BSP.
For Industrial applications the robust float type automatic liquid drainer is ideal. This is well suited due to its continuous draining and ability to handle variable loads effectively. We offer cast iron body and 316 stainless steel body units, both of which have stainless internals.
Air vents vacuum breakers air release valve and liquid drainers are all automatic valves. As they require very little maintenance they are often forgotten in maintenance schedules always so remember to check them at least annually.
Expansion Joints – This range is currently being updated (expanded :)) for further details contact us
Expansion Joints cover a variety of designs but in essence allow for pipeline movement as a result of thermal expansion and contraction, geological disturbances or operational issues such as water hammer. The most basic is referred to as the rubber expansion joint which used to be termed as a vibration eliminator.
Reinforced Rubber Bellows
They are a reinforced rubber bellows type and can be single, double or even triple sphere variety. The most common application for these is adjacent or on pump skids. Here they do an excellent job reducing vibration in pipework while handling minor angular pipework irregularities, some compression and expansion. Generally, they are used on liquid / water applications handling temperatures from -15°C to 90°C however with the correct elastomer selection they will handle other applications such as low-pressure steam, hot water, chemicals, food, potable water, oils and slurries. They are usually an off the shelf item up to 600mm (although available to 3200mm). All other types of expansion joints are made to order.
Metal Expansion Bellows
The next step up is the metal expansion bellows which moves away from vibration into the true expansion and angular movement and they can incorporate limit rods which limit over compression and over extension of the element. Where larger forces are expected addition reinforcement such as hinged stay bars should be considered. In terms of preference axial displacement is better than angular which in turn is better than lateral.
Sliding Joint
The sliding joint type is also sometimes considered and are an anchored joint and used for expansion and contraction only NOT for any type of pipework misalignment. Usually a gland packing is required hence requires routine checking and or maintenance similar as to what would be on your typical gate type valve.
Expansion Loops
Expansion loops were first type of expansion compensator used when steam came into use in the “industrial revolution”. They are still the preferred type in most industries as they are well designed / robust and less vulnerable to mechanical failure. They are also known as horseshoe loops or lyre-bird bends and usually constructed from the same materials as the pipework. Most are fully welded while some incorporate flanged joints. Typically, they are 25mm to 300mm pipework. An extension of this type of loop is used in Refineries and gas pipelines installed upright or horizontal. The only real limiter is the required space mainly on the larger sizes. We can assist with all these variants and glad to help with advice.
Due to the variables in each system there is no “typical” data sheet for the Lyre Bird bend type expansion joints, each is fabricated to suit the application. Options of incorporating expansion bellows and tie rods into the units is also becoming more prevalent.