The volume of air flowing through a baghouse divided by the total filter cloth area. It is a key design number. A ratio that is too high for the dust loads the bags faster, raises differential pressure and shortens bag life. Related service: Air-to-cloth ratio →
Angular misalignment
A shaft alignment condition where the centerlines of two coupled shafts meet at an angle instead of running parallel. It loads bearings and couplings unevenly and is measured and corrected during a laser alignment. Related service: Angular misalignment →
B
Baghouse
A dust collector that pulls dirty air through fabric filter bags, which trap dust while clean air passes through. Collected dust is cleaned off the bags and drops into hoppers for removal. Related service: Baghouse →
Brick press
A high-tonnage press, usually hydraulic, that compacts refractory mix into brick and shapes inside a mold. Press condition directly affects brick density and dimensions. Related service: Brick press →
C
Cavitation
The formation and collapse of vapor bubbles in a pump when the pressure at the inlet drops too low. It causes noise, vibration and pitting damage to impellers and casings. Related service: Cavitation →
Confined space
A space large enough to enter but with limited ways in and out and not designed for continuous occupancy, such as a tank, hopper, pit or duct. Permit-required confined spaces need atmospheric testing, a permit and an attendant before entry. Related service: Confined space →
D
Dial indicator
A precision gauge that measures small movements with a needle on a graduated dial. Millwrights use dial indicators to check runout and to align shafts, and to verify laser alignment readings. Related service: Dial indicator →
Differential pressure
The pressure difference between two points in a system, such as the dirty and clean sides of a baghouse or the inlet and outlet of a filter. Tracking it shows when filters are loading, leaking or not cleaning properly. Related service: Differential pressure →
Dynamic balancing
Balancing a rotor while it spins, correcting heavy spots in 1 or 2 planes so the rotor runs without excess vibration. It is the standard method for fan wheels, rolls and other rotors that are wide or run fast. Related service: Dynamic balancing →
G
Gearbox backlash
The small clearance between meshing gear teeth that lets them mesh without binding. Too little backlash causes heat and wear, while too much causes noise and impact loads. It is set and checked during a gearbox rebuild. Related service: Gearbox backlash →
Grouting
Filling the space between a machine base and its concrete foundation with cement or epoxy grout. Good grout supports the base evenly, resists vibration and helps alignment hold over time. Related service: Grouting →
H
Hardfacing
Welding a wear-resistant alloy onto the surface of a part to protect it from abrasion, impact or erosion. It is common on crusher parts, chutes, fan blades and other components that handle abrasive material. Related service: Hardfacing →
Hot work permit
A written authorization required before welding, cutting, grinding or other spark-producing work in an area where fire is a risk. It confirms the area has been checked, combustibles removed or protected, and a fire watch assigned. Related service: Hot work permit →
Hydraulic accumulator
A pressure vessel that stores hydraulic fluid under pressure, usually against a gas precharge. It supplies fast bursts of flow, smooths pressure and stores energy, which means it must be safely discharged before hydraulic work begins. Related service: Hydraulic accumulator →
I
Impeller
The rotating part of a pump or fan that moves fluid or air. Wear, buildup or damage to an impeller reduces performance and can cause imbalance and vibration. Related service: Impeller →
J
Jacketed pipe
A pipe inside a larger pipe, with a heating or cooling medium such as steam, hot oil or glycol flowing through the outer jacket. It keeps the product in the core pipe at a steady temperature. Related service: Jacketed pipe →
Job hazard analysis (JHA)
A written review of a job's steps, the hazards in each step and the controls that will be used. Crews complete a JHA before starting work so everyone knows the risks and the plan. Related service: Job hazard analysis (JHA) →
L
Laser alignment
A method of aligning coupled rotating shafts using laser emitters and detectors mounted on each shaft. The system measures offset and angularity and calculates the shim and move corrections. Related service: Laser alignment →
Load cell
A sensor that converts force or weight into an electrical signal. Load cells are used in industrial scales, hoppers, presses and tension systems to measure weight or force. Related service: Load cell →
Lockout/tagout (LOTO)
A safety procedure that isolates all energy sources on a machine and locks them in the off position before work begins. Each worker applies a personal lock and tag, and zero energy is verified before anyone starts. Related service: Lockout/tagout (LOTO) →
M
Mechanical seal
A seal that prevents leakage where a rotating shaft passes through a pump or mixer housing. It uses 2 flat faces, one rotating and one stationary, pressed together. Misalignment and vibration are common causes of seal failure. Related service: Mechanical seal →
Millwright
A skilled tradesperson who installs, aligns, repairs, moves and maintains heavy industrial machinery. Millwright work includes rigging, precision measurement, rebuilding and alignment. Related service: Millwright →
Mold box (die)
The cavity in a brick press that holds the refractory mix and gives the brick its shape when the press compacts it. Mold boxes and their liners wear from the abrasive mix and are replaced or reworked on a schedule. Related service: Mold box (die) →
N
Nondestructive testing (NDT)
Inspection methods that find cracks, flaws and thickness loss without damaging the part. Common methods include visual, dye penetrant, magnetic particle, ultrasonic and radiographic testing. Related service: Nondestructive testing (NDT) →
O
Offset (parallel) misalignment
A shaft alignment condition where the centerlines of two coupled shafts are parallel but not on the same line. It is measured in both the vertical and horizontal planes and corrected by moving or shimming the machine. Related service: Offset (parallel) misalignment →
Orbital welding
An automated TIG welding process where the welding head travels around a fixed tube. It produces consistent, smooth welds and is widely used for sanitary stainless tubing. Related service: Orbital welding →
P
Passivation
A chemical treatment that removes free iron and contaminants from stainless steel surfaces and restores the protective oxide layer. It is often done after welding or fabricating sanitary stainless systems. Related service: Passivation →
Predictive maintenance
Maintenance based on the measured condition of equipment, using tools such as vibration analysis, oil analysis and thermography. Work is scheduled when the data shows a problem developing, rather than on a fixed calendar. Related service: Predictive maintenance →
Preventive maintenance (PM)
Maintenance done on a set schedule to prevent failures, such as inspections, lubrication, adjustments and part replacements. A PM program catches wear before it stops production. Related service: Preventive maintenance (PM) →
Programmable logic controller (PLC)
An industrial computer that controls machines and processes based on inputs from sensors and switches. PLCs run conveyors, presses, packaging lines and most automated plant equipment. Related service: Programmable logic controller (PLC) →
Pulse-jet cleaning
A baghouse cleaning method that fires short blasts of compressed air down into the filter bags. The pulse flexes the bags and knocks the dust cake off into the hopper while the collector stays online. Related service: Pulse-jet cleaning →
Purge (back purge)
Filling the inside of a pipe or tube with an inert gas, usually argon, while welding. The purge keeps oxygen off the back of the weld, preventing oxidation and producing a clean, smooth interior. Related service: Purge (back purge) →
R
Refractory
A material that withstands very high temperatures without breaking down, such as firebrick and castable refractory. Refractories line furnaces, kilns, ladles and other high-heat equipment. Related service: Refractory →
Rigging
The planning and equipment used to lift and move heavy loads safely, including slings, shackles, chain falls, cranes and jacks. Good rigging starts with knowing the load weight, center of gravity and lift path. Related service: Rigging →
Rotary airlock
A rotating valve with vanes that discharges dust or bulk material from a hopper while keeping air from leaking through. Worn airlock tips and seals let air in, which hurts dust collector performance. Related service: Rotary airlock →
Runout
How much a shaft, coupling or rotating surface wobbles or moves off center as it turns. It is measured with a dial indicator, and excess runout points to a bent shaft or bad fit. Related service: Runout →
S
Sanitary weld
A smooth, full-penetration weld on stainless tubing with no crevices or roughness inside where product or bacteria can collect. Sanitary welds are required on product-contact piping in food, beverage and pharmaceutical plants. Related service: Sanitary weld →
Shim
A thin, precisely sized piece of metal placed under a machine foot to adjust its height. Millwrights use shims to correct soft foot and vertical misalignment. Related service: Shim →
Soft foot
A condition where one or more machine feet do not sit flat on the base, so the machine frame distorts when the bolts are tightened. It should be corrected before alignment, or the alignment will not hold. Related service: Soft foot →
Spool
A prefabricated section of piping with flanges, fittings or branches already welded in place. Spools are built in a shop and installed in the field to shorten installation time. Related service: Spool →
Static balancing
Balancing a rotor in a single plane so it does not roll to a heavy spot when at rest. It works for narrow rotors, while wider rotors usually need dynamic balancing. Related service: Static balancing →
T
Turnaround (outage)
A planned shutdown of a plant or process unit for maintenance, inspections, repairs and upgrades that cannot be done while running. Turnarounds run on tight schedules and depend on careful planning. Related service: Turnaround (outage) →
V
Variable frequency drive (VFD)
An electronic drive that controls motor speed by changing the frequency and voltage supplied to the motor. VFDs allow soft starts and speed control on fans, pumps and conveyors. Related service: Variable frequency drive (VFD) →
Vibration analysis
Measuring and studying the vibration of rotating equipment to find problems such as imbalance, misalignment, looseness and bearing wear. It is a core tool of predictive maintenance. Related service: Vibration analysis →
