Steam is simply the gas that is formed when water is heated to its boiling temperature at a given pressure.
A tea kettle is the most common example of producing steam by heating water to its boiling temperature (212˚F). In this case, the steam does not develop any pressure and is released into the atmosphere.
A boiler will generate steam under pressure by heating a large quantity of water in a contained system. This pressurized steam will travel throughout the pipes in the system to where it is needed. In addition to being created from water, which is readily available and relatively inexpensive, steam has many other advantages that make it easy and efficient to work with.
Steam coming from the boiler is distributed throughout the system by pipes referred to as steam mains or steam supply lines. Since steam is generated under pressure at the boiler, it will travel on its own through the system. Steam may travel in pipes at velocities exceeding 90 mph; for this reason, care should always be taken to open and close valves slowly.
When steam releases its heat energy, it condenses from a gas back to a liquid. This “condensed” steam is referred to as condensate, which is nothing more than extremely hot water.
Since steam is created from water, it will condense back to water after releasing its energy during heating. This water, or condensate, must be removed to not only ensure proper heat transfer, but system safety as well.
Condensate will form in steam pipelines due to radiation losses through the pipe walls. Drip Traps remove condensate from steam pipelines. However, the bulk of the condensate formed in the system occurs in the heat exchangers and other processes, and must be removed or the system would ﬁll with water and impede the heat transfer process. In contrast to drip traps, Process Traps remove condensate from the actual process application (such as a heat exchanger). Now that a basic understanding of steam has been provided, let’s introduce the typical pieces of equipment used to control, protect and optimize steam systems
The purpose of the steam trap is to allow Condensate and air to be discharged from the steam system while preventing the loss of live steam. The steam trap is a special type of valve which opens when condensate and air are present and closes when steam tries to pass.
Steam Distribution and Condensate Collection Manifolds:
Steam distribution manifolds facilitate the distribution of steam to various user points, through Forged units with inbuilt Piston valves. Similarly condensate from these points can be collected through the condensate collection manifolds, consisting of trap with associated isolation and by-pass piston valves. Available in basic configurations of 4 stations/tracing lines, and multiples of 4 stations i.e.8, 12 and 16 tracing lines.
A standard steam distribution Manifold would consist of a Manifold with Strainer, Isolation Piston valve at the Inlet at the top, and a Trap valve station at the bottom drain point.
A standard Condensate collection Manifold would consist of a Manifold with Intelligent Trap valve stations at the individual tracing lines.
Steam distribution manifolds, Condensate collection manifolds, steam trap stations, steam traps, and pre-insulated tubing.
Drip Legs are used for removing condensate from steam transmission and distribution lines. This helps ensure high quality steam for use in various plant applications and also will prevent damaging and dangerous water hammer.
As steam travels at high velocity through piping, condensate forms as the result of piping heat losses and/or improper boiler control resulting in condensate carryover. Drip legs are therefore located at points where condensate may accumulate to allow for drainage by gravity down to a steam trap for proper discharge from the system. Since condensate drains by gravity, drip legs must be located on the bottom of piping and designed with diameters large enough to promote collection.
Properly sized and constructed Drip legs include a steam traps remove the condensate from the steam lines. These are typically referred to as drip application traps where the process traps remove condensate being generated by the actual process.
Drip legs should be placed 150 to 300 feet apart on straight runs of piping, before elevation changes, and before critical equipment such as Regulators and Control Valves.
Air/ Steam Moisture Separators:
Separators are used for the removal of entrained moisture in steam and compressed air lines. Wet steam enters the inlet of the separator where it is deflected in a centrifugal downward motion. The entrained moisture is separated out by reduction in velocity. Separated liquid then falls below the Vortex Containment Plate where it cannot be re-entrained. Dry steam or air then flows upward and exits through the outlet of the separator. Separators should be placed before all regulating valves to eliminate problems caused by water logging and wire drawing of the valve seats
Pressure Motive Pumps (PMPs)
Pressure Motive Pumps (PMPs) are non-electric pumps which return condensate back to the boiler room, using steam pressure as the motive force. PMPs can be supplied as stand-alone units – which include a pump tank, the internal operating mechanism, and a set of inlet and outlet check valves, or: as a packaged system – which also includes the vented receiver tank (to collect the condensate) mounted on a common base.
Condensate from several different sources, at different pressures, are often discharging into the same return line. The discharge from one of the higher-pressure sources could easily increase the pressure in the return line, which would stop the discharge from a critical process application operating at lower pressures. By connecting the condensate return line to a vented receiver, the pressure in the return line will be effectively equalized to atmospheric pressure, allowing condensate to freely drain from all condensate sources. This is an extremely important and often overlooked aspect of any properly operating steam and condensate return system. The receiver and vent must be adequately sized to allow for the discharge of flash steam without building up excessive pressure. Higher condensate pressures or loads would require larger receiver and vent sizes. Condensate then flows by gravity from the vented receiver to the condensate return pump and is then returned back to the boiler room.
For Condensate collection and pumping systems (pressure motive pumps):
Steam Pressure & Temperature Regulators and Control Valves
The HD-Series Pilot-Operated Regulators are used on steam applications for pressure reduction or controlling product temperature (when steam is used in heating applications). The Pilot-operated regulators are more accurate and available in higher capacity than Direct-Operated regulators. The HD Series regulators use a pilot valve (several types and styles including Pressure, Temperature, ON-OFF solenoid, etc) to control the operation of the Main Valve. The HD series has a Ductile Iron Body; Pilot and Main-Valve are selected separately.
For steam pressure and temperature regulators:
For Control valves:
For Mechanical level controls for deaerators and boilers: