A
B
C
D
E
F
G
H
I
L
M
N
O
P
R
S
T
U
V
W
Y

P

PARTICLE
Any discrete unit of material structure: a discernible mass having an observable length, width, thickness, size, and shape.

PARTICLE SIZE DISTRIBUTION
The size range and quantity of particles which are measurable in a dry or liquid sample. Used to determine the appropriate filter media for a specific process.

PARTICULATE
Any solid or liquid material in the atmosphere.

PART NUMBER
A number used to describe a unique item. Each bag, cage and accessory item has its own part number.

PATTERN
The total layout of a given bag. Shows all marks and cut lines.

PERMEABILITY
A measure of fabric porosity or openness, expressed in cubic feet of air per minute per square foot of fabric at a 0.5" w.c. Pressure differential.

PH
A value of indicating the acidity or alkalinity of a material. A pH of 7.0 is neutral, less than 7.0 is acidic, and more than 7.0 is basic.

PHOTOHELIC GAUGE
An instrument used to measure differential pressure and control it with adjustable set points for the desired operational differential pressure.

PICK
A single filling thread carried by one trip of the filling yarn insertion device (shuttle) across a loom. The picks interlace with the warp ends to form a woven fabric.

PINCH
The amount of looseness of a bag on a cage. Measured by the amount of fabric that can be grasped between the thumb and forefinger; both up and down directions of the fabric are measured.

PITOT TUBE
Device consisting of two tubes used to measure velocity pressure. One tube measures total air stream pressure, the other measures static pressure. When both tubes are connected across a differential pressure-measuring device, static pressure is compensated and velocity pressure only is measured.

PLEATING
The overlapping of a gathered fabric in a wave-like action and screw down. Caused by fabric stretch or trying to place a larger piece of fabric over a smaller one.

PLENUM
An air compartment maintained under pressure, and connected to one or more ducts.

PM10
A US EPA standard that includes additional controls on particulates sized 10 micron and smaller.

PM2.5
A US EPA standard that includes additional controls on particulates sized 2.5 micron and smaller.

PLIED YARN
A yarn formed by twisting together two or more single yarns in one operation.

POLYESTER
Any of several polymeric resins formed chiefly by condensing polyhydric alcohol's with dibasic acids. Fibers formed are woven.

POLYPROPYLENE
Polymerized polypropylene thermoplastic resin used primarily as a coating.

PORE
Small interconnecting passage through a membrane. The size and irregular path of a pore determines the removal efficiency of a membrane.

PORE SIZE
The equivalent diameter of the smallest part of any channel through a membrane.

POROSITY
The percent of open areas per unit volume of fabric.

POPPET VALVE
A valve utilized to isolate compartments and/or allow for reverse airflow through individual compartments. Typically constructed of a flat wafer plate assembled on the end of the shaft of an air cylinder, which drives the wafer (poppet) into position.

POSITIVE PRESSURE BAGHOUSE
A system with a fan located prior to the baghouse on the dirty side, pushing air through the system.

PRECOAT
Material added to the air stream on initial process start-up to aid in establishing an initial dustcake on the filter bags.

PRESSURE
An increase in the force exerted on something above standard atmospheric conditions, measured as gauge pressure (psig, bar g).

PRESSURE DROP
A measure of the resistance the gas stream encounters as it flows through the baghouse. May refer to pressure differential across the cloth, across the baghouse, or the pressure drop across the entire system.

PREVENTION COSTS
The costs of any action taken to investigate, prevent or reduce defects and failures in the future. These costs can include planning, training and setting up a system.

PROCESS
Any operation in a business.

PROCESS CAPABILITY
The limits of inherent variability within which a process operates as governed by the prevailing circumstances.

PROCESS COLLECTOR
A collector of manufacturing or processing equipment to capture product typically lost as emissions.

PROCESS FILTRATION
Filtration used as an active part of producing finished products.

PSI
Pounds per Square Inch; a unit of pressure; 1 psi equals 27.7" water gauge or 2.04" mercury (Hg).

PTFE
Polytetraflouroethylene. Highly durable and resistant to a broad range of temperatures and chemicals. Used to form a heat-bonded, expanded membrane on filter media to provide high efficiency among other properties. PTFE is hydrophobic.

PULSE CYCLE
On a pulse-jet baghouse, the interval of time between one pulsing of a row of bags and the next pulsing of the same row.

PULSE DURATION (ON TIME)
The length of time a pulse lasts, generally described as the length of time the electrical signal holds the solenoid pilot valve open. However, due to mechanical losses, the time the diaphragm is open will vary.

PULSE INTERVAL (OFF-TIME)
Elapsed time between pulses in a pulse-jet collector.

PULSE-JET BAGHOUSE
A baghouse using short intermittent bursts (pulses) of compressed air to clean dust/particulate from filter bags that are supported by cages. The particulate is collected on the outside of the filter bags.

PYRAMID HOPPER
A hopper shaped like an inverted pyramid.