| Positive Pressure Gauge | Approximately 0–1 bar to 0–25 bar, depending on the exhaust system | Engine exhaust back pressure, industrial ducts, combustion equipment, and process gas lines operating above atmospheric pressure | Commonly Class 1.0, 1.6, or 2.5; analog pointer or digital LCD display | Usually radial or rear threaded connection; stainless steel or copper-alloy wetted parts; typical threads include G, NPT, or metric forms | Select a gauge designed and tested in accordance with applicable pressure-gauge requirements such as EN 837-1 or ASME B40.100; verify local pressure-equipment rules | Install at a representative pressure point, avoid excessive vibration, use a suitable seal, and confirm that the connection thread matches the system | Inspect for pointer drift, blocked ports, leakage, and case damage; calibrate at least annually or according to the site quality program | Confirm pressure unit, thread standard, temperature rating, corrosion resistance, and required documentation before import or installation |
| Compound Pressure and Vacuum Gauge | Typical scales range from -1 bar vacuum to 0.6, 1.5, 2.5, or 4 bar positive pressure | Exhaust systems that may experience both suction and positive back pressure, including fans, extractors, and air-handling equipment | Usually Class 1.6 or 2.5; dual-scale dials may show bar and psi or kPa | Threaded process connection; brass or stainless steel pressure components; optional liquid-filled case for vibration reduction | Use a pressure range that covers both the vacuum and positive-pressure conditions; select units and dial markings suitable for the destination market | Install with the zero point visible, keep the pressure port free of condensate and soot, and avoid exceeding either scale limit | Check zero return and both scale directions during routine inspections; clean the sensing path and recalibrate after overload or abnormal readings | Useful for multi-market equipment, but buyers should verify whether the selected scale and unit system are accepted by local operators and inspectors |
| Differential Pressure Gauge | Commonly 0–25 Pa, 0–250 Pa, 0–2.5 kPa, or higher for duct and filter applications | Filter blockage monitoring, scrubber systems, ventilation ducts, exhaust fans, and pressure loss across silencers or heat exchangers | Typically 1.5–2.5% of full scale for mechanical models; digital models may offer configurable units and alarm outputs | Two pressure ports marked high and low; tubing connections are common; diaphragm or capsule sensing elements are selected according to pressure and media | For safety-related or regulated equipment, verify applicable ventilation, emissions, electrical, and measurement requirements in the destination country | Connect high and low ports correctly, route impulse tubing without sharp bends, and protect low-range instruments from condensation and dust | Check both ports for blockage, compare the zero reading with the system at equal pressure, and test alarm thresholds during scheduled service | Specify differential range rather than only line pressure; confirm tubing size, alarm functions, enclosure rating, and replacement availability |
| High-Temperature Exhaust Gauge | Often 0–1 bar, 0–2 bar, or 0–5 bar with a remote sensing point | Diesel and gas engine exhaust, kilns, furnaces, incineration systems, and high-temperature process exhaust | Accuracy depends on the gauge and cooling arrangement; a remote diaphragm seal, impulse line, or cooling coil is commonly required | Stainless steel pressure parts are preferred for corrosive or hot gases; connection materials must tolerate the measured temperature | Verify maximum process temperature, ambient temperature, pressure rating, materials compatibility, and any applicable exhaust-emission equipment requirements | Do not expose a standard gauge directly to gas above its rated temperature; use a cooling element, sufficient impulse-line length, and thermal shielding where necessary | Inspect for heat discoloration, hardened seals, blocked impulse lines, and thermal fatigue; recalibrate after overtemperature exposure | Temperature rating is often more important than nominal pressure range; request temperature derating data and material certificates for demanding service |
| Liquid-Filled Pressure Gauge | Commonly 0–1 bar to 0–25 bar; range should place normal operation near the middle of the dial | Vibration-heavy engines, mobile equipment, compressors, pumps, and exhaust systems with mechanical pulsation | Often Class 1.0 or 1.6; filling liquid dampens pointer movement and improves readability under vibration | Stainless steel case and process components are common; fill liquid must be compatible with the operating temperature and environment | Check enclosure and ingress-protection requirements, temperature limits of the fill liquid, and pressure-gauge conformity documentation | Mount upright where possible, use a snubber or restrictor for severe pulsation, and leave any manufacturer-provided vent in the correct position | Look for fill discoloration, leakage, condensation, and pointer instability; replace damaged gauges rather than refilling them in the field unless designed for service | Confirm low-temperature performance, shipping orientation, case sealing, and whether the fill liquid is acceptable for the installation environment |
| Digital Exhaust Pressure Gauge | Ranges may extend from low differential pressure to several hundred bar, depending on the sensor design | Remote monitoring, data logging, engine diagnostics, filter condition monitoring, and systems requiring switch or transmitter outputs | Typical stated accuracy is approximately 0.25–1.0% of full scale; display units may include Pa, kPa, bar, psi, or inH₂O | Electrical output may include switch, analog, or digital communication; choose sensor materials and seals compatible with the exhaust medium | For powered equipment, verify applicable EMC, electrical safety, ingress-protection, hazardous-area, and national conformity requirements | Provide correct power supply, cable protection, grounding, strain relief, and signal isolation; locate the sensor away from direct exhaust heat unless rated for it | Check battery or power status, compare readings with a calibrated reference, inspect wiring, and verify alarm set points at planned intervals | Evaluate software, connector type, IP rating, language requirements, cybersecurity needs, spare sensors, and long-term availability of replacement batteries |
| Panel-Mount Exhaust Gauge | Selected according to the equipment design, commonly 0–1 bar, 0–2 bar, or 0–10 bar | Control cabinets, engine instrument panels, generator sets, boiler panels, and operator stations | Analog versions commonly use 63–100 mm dial sizes; digital versions provide numerical display and optional alarm indication | Rear connection or remote pressure line; front bezel and case should match the panel cutout and required enclosure protection | Verify panel cutout, enclosure rating, vibration resistance, electrical conformity, and measurement accuracy requirements | Use a secure panel gasket, support long impulse lines, prevent line vibration, and ensure the dial remains readable from the operator position | Inspect bezel, lens, mounting hardware, and connections; test the indicated pressure against a reference gauge during planned shutdowns | Confirm cutout dimensions, viewing angle, unit markings, spare-panel compatibility, and availability of local service or replacement parts |
| Remote-Mount Gauge with Impulse Line | Commonly 0–1 bar to 0–25 bar, with the range matched to the expected exhaust back pressure | Hot, inaccessible, vibrating, or hazardous exhaust points where the display must be installed away from the process connection | Accuracy depends on the gauge and the impulse-line installation; response time may be slower than direct mounting | Small-bore stainless steel or high-temperature tubing with compression fittings is common; isolation valves and test points are recommended | Pressure tubing, fittings, isolation valves, and gauge must all meet the applicable pressure, temperature, and material requirements | Route tubing continuously where possible, avoid low points that collect condensate, protect it from mechanical damage, and provide adequate support | Drain or clean the impulse line when permitted, check fittings for leaks, confirm response time, and calibrate the gauge with the line included in the test setup | Review tube dimensions, fitting standards, spare tubing availability, export packaging, and installation practices used in the destination region |
