Boiler glossary

Boiler glossary P

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PACKAGE BOILER -- A boiler equipped and shipped complete with fuel burning equipment, mechanical draft equipment, automatic controls, and accessories.
PADDLE STEAMER -- steamships with a paddle wheel on each side of the hull .
PANTING -- Pulsating movement in a burner. Panting might occur when the burner operates with a considerable deficiency of air. Decrease the fuel supply slowly.
Panting may also depend on too high oil temperature that causes vaporization in the burner tip.
PARAFFINIC HYDROCARBONS -- Straight-chain hydrocarbon compounds with the general formula CnH2n+2   e.g., Propane = C3H8
PARSON'S STEAM TURBINE -- A reaction turbine in which rings of moving blades of increasing size are arranged along the periphery of a drum of increasing diameter. Fixed blades in the casing alternate with the blade rings. Steam expands gradually through the blading, from inlet pressure at the smallest section to condenser pressure at the end.
PERFECT COMBUSTION -- Stoichiometric combustion. The complete oxidation of all the combustible constituents of a fuel, utilizing all the oxygen supplied.
PETROLEUM -- Naturally-occurring green to black coloured mixtures of crude hydrocarbon oils, found as earth seepages or obtained by boring. Petroleum is widespread in the earth's crust, notably in the US, Russia and the Middle East. In additions to hydrocarbons of every chemical type and boiling rage, petroleum often contains compounds of sulphur, vanadium, etc. Commercial petroleum products are obtained from crude petroleum by distillation, cracking, chemical treatment, etc.
pH VALUE -- A logarithmic index for the hydrogen ion concentration in an aqueous solution. Used as a measure of acidity of a solution; given pH = log10 (1/[H+]), where [H+ ] is the hydrogen ion concentration. A pH below 7 indicates acidity, and one above 7 alkalinity.
PILOT BURNER -- A flame which is utilized to ignite the fuel at the main burner or burners.
PINCH POINT TEMPERATURE -- It is the difference between the temperature of the gas leaving the evaporating section in the boiler and the saturation temperature corresponding to the steam pressure in the evaporator tubes.
PISTON SLIDE VALVE -- A steam-engine slide valve in which the sealing or sliding surfaces of the valve are formed by two short pistons attached to the valve rod, working over cylindrical port faces in the steam chest.
PITOT TUBE -- An instrument that will register total pressure and static pressure in a gas stream, used to determine its velocity.
PITTING -- Corrosion of metal surfaces due to local chemical actions.
PNEUMATIC SYSTEM -- A compressed air system, used commonly for controls.
POST PURGE -- A method of scavenging the furnace passes to remove all combustible gases befor ignition of the main burner.
PREHEATED AIR -- Air at a temperature exceeding that of the ambient air.
PRESSURE RELIEF VALVE -- Safety valve. A device mounted on a boiler, which is designed to release any high steam pressure and thus prevent boiler explosions.
PRIMING -- The delivery of steam containing water in suspension, due to violent ebullition or frothing. It is generally caused by a high water level in the boiler.
PROCESS STEAM -- Steam used for industrial purposes other than for producing power.
PRODUCTS OF COMBUSTION -- The gases, vapors, and solids resulting form the combustion of fuel.
PREHEATED AIR -- Air at a temperature exceeding that of the ambient air.
PRESSURE JET ATOMIZER -- Utilizes the supply pressure energy to atomize the fuel into a spray of finely dispersed droplets.
PRESSURE RELIEF VALVE -- Safety valve. A device mounted on a boiler, which is designed to release any high steam pressure and thus prevent boiler explosions.
PRUD'HON CAPUS BOILER -- A Scotch boiler variant.
PS -- Paddle Steamer, steamships with a paddle wheel on each side of the hull .
PYROMETER -- An electrical thermometer for measuring high temperatures.