| PACKAGE BOILER -- A boiler equipped and shipped
complete with fuel burning equipment, mechanical draft equipment, automatic
controls, and accessories.
PADDLE STEAMER --
PS, 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.
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.
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 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.
PRIMING -- The delivery of steam containing water in
suspension, due to violent ebullition or frothing.
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.
PS --
Paddle Steamer, steamships with a paddle wheel on each
side of the hull .
PYROMETER -- An electrical thermometer for measuring high
temperatures.
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