Advanced Boiler Efficiency & Water Treatment – knowledge to overcome the issues that arise with regards to boiler water systems involving aspects of boiler water chemistry, advanced options in pre-treatment and internal treatment, various water treatment strategies using appropriate international water quality standards and codes, strategic techniques in controlling water chemistry and the measures to optimise boiler efficiency and operation
Alkalinity – pH values above 7
Antifoam – A substance added to boiler water to control foaming in impure water that experiences rapid circulation currents
Blowdown – Partial venting or draining, under pressure, of the water side of a boiler to reduce or remove unwanted contaminants. Also the pressure drops after releasing a pressure-relief valve
Boiler Plug – A threaded plug of solid construction fitted to boilers. Removal allows inspection and washing out.
Button Plug – A form of fusible plug containing a fissile material and a solid core of none fissile material. On overheating the fissile material melts releasing the solid core. The stated advantage is failure is complete, that is the entire diameter of the plug’s central hole is opened on melting of the fissile material. A plug with a core of fissile material only can partially melt, leading to a very small discharge of steam and water, which can lead to low water levels not being brought to the attention of the operators. Also known as a drop plug.
Carrier – A well known company traditionally known for manufacturing cooling systems but also produces boilers including oil fired boilers
Carbonate – An anion with a charge of -2. In the context of Porta Treatment carbonate ions form the bulk of the alkalinity in the boiler water.
Carryover – Water droplets and dissolved and suspended solids being carried out of the boiler by escaping steam
Caustic Embrittlement – A type of embrittlement in the metal at joints and the ends of tubes in steam boilers; due to the chemical composition of the boiler water; may lead to failure of the metal.
Clay – Solid particles contained within boiler feedwater. Most commonly seen at the lower points of the boiler where they form a sticky clay like substance. This clay is largely immobile and thus causes localised overheating and circulation problems.
Corrosion – The chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties.
Drop Plug – A form of fusible plug containing a fissile material and a solid core of none fissile material. On overheating the fissile material melts releasing the solid core. The stated advantage is failure is complete, that is the entire diameter of the plug’s central hole is opened on melting of the fissile material. A plug with a core of fissile material only can partially melt, leading to a very small discharge of steam and water, which can lead to low water levels not being brought to the attention of the operators. Also known as a button plug.
Feedwater – Any water which is fed into the water tanks for use in the boiler.
Feedwater Control Valve – Commonly an actuated valve controlled manually or electronically to throttle flow into the tanks.
Fibrecsope – An inspection device with an eye piece at one end of fibre optics enabling viewing of otherwise non-visible features. Normally equipped with a lamp.
Foaming – The formation of a foam layer on the surface of the boiler water. It naturally occurs in a body of impure water subject to rapid circulation currents. The greater the amount of impurities dissolved in the water the greater the propensity there is for foaming.
Fouling – Anything which adheres to boiler surfaces causing localised overheating and/or disrupts water circulation. It must also be noted that in very bad water areas fouling also occurs in water tanks, pipework, valves, injectors, clacks etc.
Gauge Frame – Attached to boilers allowing the water level to be seen or determined
Gauge Glass – Clear glass fitted to a gauge frame through which the boiler water level can be seen.
Hard Water – water that contains mineral salts (as calcium and magnesium ions)
Hand Hole – An oval opening (approximately hand sized) in the boiler plate allowing access for inspection and washing out.
Hand Hole Door – A solid oval piece of metal with a threaded shaft extending from the middle. The door fits through a hand hole (approximately hand sized) and butts against the inside of the outer boiler plate. A clamp fits over the shaft which is bolted down sealing the door against the boiler plate.
Lineside Treatment – Treating feedwater carried out prior to the water being transferred to the water tanks.
Man Hole – An oval opening in the boiler plate allowing access for inspection and washing out. Normally large enough for a person to enter the boiler. There are special safety procedures necessary for a person to enter a man hole.
Magnetite – The mineral form of black iron oxide, Fe3O4, that often occurs with magnesium, zinc, and manganese and is an important ore of iron.. Magnetite forms a layer of grey to black colored material on internal boiler surfaces giving added protection against corrosions, caustic embrittlement and fouling.
Mud – Solid particles contained within feedwater. These generally collect at the low points of the boiler where they form a sticky mud like substance.
Mud Hole – An oval opening in the boiler plate allowing access for inspection and washing out.
Polydimethylsiloxane (PDMS) belongs to a group of polymeric organosilicon compounds which are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties
Priming – Priming is the carryover of varying amounts of droplets of water in the steam (foam and mist), which lowers the energy efficiency of the steam and leads to the deposit of salt crystals on the super heaters and in the turbines. Priming may be caused by improper construction of boiler, excessive ratings, or sudden fluctuations in steam demand. Priming is sometimes aggravated by impurities in the boiler-water
Priming is common cause of high levels of boiler water carryover. These conditions often lead to super heater tube failures as well. Priming is related to the viscosity of the water and its tendency to foam. These properties are governed by alkalinity, the presence of certain organic substances and by total salinity or TDS. The degree of priming also depends on the design of the boiler and its steaming rate
ppm – parts per million, a way of expressing the amount of a substance in a liquid in the terms milligrams (of substance) per litre of liquid.
ppt – parts per thousand, a way of expressing the amount of a substance in a liquid in the terms grams (of substance) per litre of liquid.
Reflex Gauge Glass – A form of gauge glass considered to be best practice for steam boilers. A flat glass on the outer side and prisms on the water side giving a very clear indication of the water level.
Reverse Osmosis – a method of producing pure water; a solvent passes through a semi permeable membrane in a direction opposite to that for natural osmosis when it is subjected to a hydrostatic pressure greater than the osmotic pressure
Scale – A solid crust of material which generally adheres to internal boiler surfaces causing localised overheating and circulation problems. Scale can be made up of many minerals with forms of calcium and silica being very common.
Soft Water – Water with a low mineral (impurity) content.
Steam Contamination – In normal operation steam passing the throttle valve is far from pure. It will contain water droplets carried along in the “steam wind”. These droplets contain dissolved and suspended solids. Such particles build up in passages, ports, valve and piston heads/rings, gland packings and similarly in auxiliaries. Contaminated steam leads, amongst other things, to oil contamination. The contaminated oil can act as a fine grinding paste with obvious detriment to the locomotive.
TDS – total dissolved solids, a measure of the amount of substances dissolved in a liquid. Often quoted in ppm or ppt.
Tubular Gauge Glass – A tubular glass through which the boiler water shows the level.
Washout – The process of removing any solids precipitated out of the boiler water as mud or scale. Normally either using cold pressurized water or hot pressurized water
