Instrumentation, Measurement and Control - Airtrol Inc.
Instrumentation refers to devices that measure or control physical variables such as temperature, level, flow, or pressure. These products are essential in the industry because they allow for maximum output with mi...
Pressure regulators reduce and hold downstream pressure for gases and liquids. Stable pressure protects equipment, improves process control and saves energy.
Regulator Types
- Air and gas regulators – pneumatic and process gases
- Liquid regulators – water and process liquids
- Back pressure regulators – maintain upstream pressure
- Precision regulators – instrument and analytical
- High-pressure regulators – cylinders and hydraulics
Choosing a Regulator
Select inlet and outlet pressure range, flow, media and materials. Oversizing causes poor control.
Centro supplies pressure regulators for industrial systems.
Related categories: Pressure Control | Sequence Valves | Pressure Transmitters | Pressure Switch | Gauges
Pressure switches open or close an electrical contact when pressure reaches a set point. They start and stop pumps and compressors, trigger alarms and shut equipment down when pressure is unsafe.
Pressure Switch Types
- Mechanical switches – simple, reliable and no power needed
- Electronic switches – adjustable set points and displays
- Differential pressure switches – filter and flow monitoring
- Vacuum switches – vacuum system control
- Explosion-proof switches – hazardous areas
Choosing a Switch
Select set point range, deadband, electrical rating and wetted materials. Fixed or adjustable deadband affects cycling. Add snubbers for pulsating systems.
Centro carries pressure switches for pumps, compressors and process safety.
Related categories: Pressure Control | Pressure Transmitters | Gauges | Pressure Regulators | Pressure Control Accessories
Sequence valves control the order of operations in hydraulic and pneumatic circuits. They open when pressure reaches a set point, starting the next actuator only after the first has finished.
Applications
- Clamp-then-work sequences – fixtures and presses
- Multi-cylinder sequencing – coordinated motion
- Pressure-dependent operations – safe staged movement
Choosing a Valve
Select pressure range, flow, port size and pilot type. Proper sequence settings prevent premature movement.
Centro supplies sequence valves for fluid power circuits.
Related categories: Pressure Control | Pressure Regulators | Pressure Transmitters | Pressure Switch | Gauges
Subject to factory lead times
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
Subject to factory lead times
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$37.73$38.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
$36.76$37.85
Subject to factory lead times
- Selecting the right process instrument starts with defining four things: what variable you need to measure (temperature, pressure, flow, or level), the process conditions the instrument will face (media type, temperature range, pressure range, corrosiveness, and whether the environment is hazardous), the accuracy and response time your application requires, and how the measurement data needs to be communicated (local display only, 4–20 mA signal to a PLC/DCS, or digital protocol like HART or Modbus). For temperature, the choice between thermocouples, RTDs, and infrared sensors depends on the temperature range and accuracy needed. For pressure, gauge type, range, wetted materials, and whether you need local indication or a remote transmitter signal are the key decisions. For flow, the fluid properties (conductive liquid, gas, steam, slurry) determine whether a magnetic, ultrasonic, Coriolis, vortex, or variable-area meter is the best fit. For level, vessel conditions (open vs. pressurized, clean liquid vs. foam/solids) guide the choice between float switches, ultrasonic, radar, or differential pressure technologies. Centro's instrumentation specialists can help you match the right technology to your specific process conditions and budget.
- Accurate process instrumentation is the foundation of safe, efficient, and compliant operations. Every control loop — whether it manages boiler pressure, reactor temperature, tank level, or pipeline flow — depends on instruments that provide reliable, real-time measurements. If a temperature sensor reads inaccurately, a heater may overshoot and damage the product or create a safety hazard. If a level transmitter drifts, a tank may overflow or run dry. If a flow meter is undersized, the control system cannot maintain the correct feed rate. Beyond safety and quality, accurate instrumentation directly impacts energy consumption, raw material usage, and regulatory compliance. Calibrated, properly specified instruments reduce waste, prevent unplanned shutdowns, and provide the data required for regulatory reporting and quality documentation.
- A process control loop is a system that continuously measures a process variable, compares it to a desired setpoint, and adjusts an output to keep the variable at the setpoint. The loop consists of three elements: the sensor/transmitter (measures the variable — e.g., a thermocouple measuring temperature), the controller (compares the measurement to the setpoint and calculates a corrective output — typically a PID controller), and the final control element (adjusts the process — e.g., a control valve that opens or closes to change steam flow). Instruments are the eyes and ears of the loop — without accurate, responsive sensors and transmitters, the controller cannot make correct decisions, and the process drifts out of specification. The entire loop must be properly engineered as a system — sensor accuracy, transmitter range, controller tuning, and valve sizing must all be matched to the process requirements.
- Industrial instruments communicate with controllers and PLCs using standardized electrical signals. The 4–20 mA analog current loop is the most widely used signal in process instrumentation — it transmits a variable measurement as a proportional current (4 mA = zero/low range, 20 mA = full scale), and the current-based signal is resistant to voltage drop and electrical noise over long cable runs. The 0–10 V DC voltage signal is used in some HVAC and building automation applications but is more susceptible to noise and cable length limitations. Discrete (on/off) signals — from switches, relays, and transmitter alarm contacts — indicate threshold conditions like high level, low pressure, or flow/no-flow. Digital communication protocols — HART (layered on top of 4–20 mA for configuration and diagnostics), Foundation Fieldbus, PROFIBUS PA, and IO-Link — enable bidirectional communication between the instrument and the control system for advanced diagnostics, remote configuration, and multi-variable data.
- When instruments are installed in locations classified as hazardous (areas where flammable gases, vapors, or combustible dusts may be present), they must be approved for that classification to prevent ignition. Key considerations include the area classification (Class I for gases/vapors, Class II for dusts, with Division 1 for normally present hazards and Division 2 for abnormal conditions — or Zone 0/1/2 under ATEX/IECEx), the protection method (intrinsic safety, explosion-proof, non-incendive, or purged/pressurized), and the specific gas group and temperature class. Intrinsically safe (IS) instruments — used with IS barriers in the safe area — limit energy to levels too low to cause ignition and are the most common and practical approach for low-power sensors and transmitters. Explosion-proof enclosures contain any internal explosion and are used for higher-power devices. Always verify the instrument's certification (FM, CSA, ATEX, IECEx) matches the area classification before installation.