Dwyer

Low differential pressure gauge for air and non-corrosive gases that needs no power, in a die-cast aluminium housing sealed to IP67, with a four inch dial and built-in overpressure protection.

Use it whenThis is the default answer any time someone needs to see a low air pressure difference and does not want to run power or a signal, for example filter loading, room pressure or fan differential. If they need a contact or an output, move up to the Photohelic or a transmitter instead of adding a gauge plus a switch.

Combines a repeatable differential pressure switch with the large analog Magnehelic gauge face, with switch setpoints adjusted by external knobs on the face.

Use it whenSpecify this when the customer wants both indication and control from one device and wants maintenance to be able to move the setpoint without tools or a laptop. It is the right upgrade from a plain Magnehelic once an alarm, a fan interlock or a filter changeout signal is in scope.

Magnehelic gauge with an adjustable red LED setpoint indicator.

Use it whenUse this when you want a visual setpoint an operator can see across the room but you do not need switching contacts. It is a middle step between a plain gauge and a Photohelic.

Compact, economical low differential pressure gauge that needs no power.

Use it whenChoose this when panel space or budget is the constraint and a four inch dial will not fit or is not justified. Accept that you give up dial size and readability.

Differential pressure gauge rated for higher line pressure and listed as hydrogen compatible.

Use it whenReach for this when the differential is small but the static line pressure is high, which rules out a Magnehelic, and for hydrogen service. Check the hydrogen compatibility statement on the current datasheet before committing.

Digital differential pressure and differential flow gauges, factory pre-calibrated, with battery or 24 volt power options.

Use it whenGo digital when the reading has to be logged, read at low ranges where an analog needle is hard to resolve, or shown as a flow value rather than a pressure. If nobody will maintain a battery, specify the powered version.

Inline filter gauge with one eighth inch NPT connections and colour-coded green, yellow and red zones showing filter condition.

Use it whenUse this where the person reading it is not an instrument technician. The colour band means a maintenance tech can act without knowing what number is acceptable.

Piston-based differential gauge for filter pressure drop and pump performance in harsh environments.

Use it whenChoose the piston type over a diaphragm gauge when the media is dirty or the service is rough enough to worry about a diaphragm. It is the more forgiving construction.

Air velocity transmitter using a heated mass flow sensor, with sixteen field selectable ranges and optional LED indication and NIST calibration.

Use it whenPick this as the general purpose duct air velocity transmitter, especially when one part number has to cover several ranges across a building. The field selectable ranges are the reason to standardise on it.

Heated mass flow air velocity transmitter intended for dirty air flow applications, listed for HVAC, fan supply, exhaust tracking and cleanroom ventilation monitoring.

Use it whenMove to the B when the air is not clean, for example exhaust or a dusty return. Putting a standard sensor in dirty air is the usual cause of drift complaints.

Air velocity transmitter with the same heated mass flow sensor on a remote probe.

Use it whenUse the remote probe version when the electronics cannot live at the measuring point, for instance a high duct, a hot plenum, or a cleanroom wall where you want the enclosure outside.

Air velocity transmitters for variable air volume systems, with airflow and volumetric flow output and, on the AVLV, BACnet and Modbus communications.

Use it whenChoose AVLV when the building automation system wants the value on a network rather than as an analog signal, and when the tighter accuracy class is called for. AVUL is the simpler VAV option.

Pencil-style air velocity transmitter using thermal anemometer technology, with configurable outputs.

Use it whenUse the pencil style where the probe has to go through a small penetration in a duct or cleanroom wall and there is no room for a housing at the measuring point.

Direct reading precision variable area flowmeters for gas and liquid, in two inch, five inch and ten inch scales, panel or surface mountable, with optional precision metering valves.

Use it whenUse a rotameter when an operator needs to set and see a flow locally and no signal is required, for example a purge, a sample line or a cooling loop. Choose the longer scale when the reading has to be resolved finely, and add the metering valve if the operator will be adjusting it.

Variable area flowmeters in precision machined acrylic blocks for full visual inspection of flow, in two inch and four inch scales with optional precision metering valves.

Use it whenChoose Visi-Float over Rate-Master when seeing the fluid itself matters, for instance confirming a line is actually wet and clear. Suited to air, water and process gas.

Regulator kits for Rate-Master and Visi-Float flowmeters that hold a constant pressure differential.

Use it whenAdd these when upstream pressure will not hold steady, because a rotameter reading is only meaningful at a known pressure. Skip them if the supply is already regulated.

Insertion paddlewheel flowmeters for liquid monitoring in brass and 316 stainless steel with a 4-20 mA output.

Use it whenUse insertion paddlewheel when you need a flow signal back to the control system on clean water or similar liquid at modest cost. It is the wrong choice on dirty, stringy or abrasive liquid, where the rotor will foul.

Switches that make or break on flow in liquid, gas, air, water and process systems, including paddlewheel and threaded plastic pipe styles.

Use it whenSpecify a switch, not a meter, when the only question is whether flow is present, such as pump dry-run protection or proof of cooling flow. It is far cheaper than measuring a value nobody uses.

Devices that indicate whether material has reached a defined level point.

Use it whenChoose point level when the requirement is an alarm, an interlock or a pump start and stop. Do not buy continuous measurement to answer a yes or no question.

Sensors and transmitters that provide ongoing level measurement rather than a single alarm point.

Use it whenChoose continuous when inventory, batching or trending is the point, or when several setpoints would otherwise mean several switches.

Devices that turn level information into operator indication, relay action, pump control or valve control.

Use it whenInclude one of these when the level signal has to do something locally and there is no PLC in the picture, which is common on small skids and lift stations.

Products used to identify unwanted water before it damages equipment, interrupts service or creates facility maintenance issues.

Use it whenPitch this for data centre floors, telecom rooms, mechanical rooms and anywhere a small water escape is expensive. It is a facilities sale rather than a process sale.