Instrumentation · Readable, protected and right-ranged
Ashcroft lists six primary reasons pressure instruments fail audits: excessive pulsation or vibration, operation outside temperature limits, pressure spikes, clogging, corrosion and improper installation. Pick the range so normal pressure sits mid-scale, add the protection the service needs, and size the dial so the required accuracy can actually be read.
Mechanical dial pressure gauges for process lines, tanks, pumps, compressed air and water treatment, including stainless, liquid-filled and sanitary clamp-connected diaphragm gauges. Electronic pressure transmitters are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 5 sources
Choose the range so normal pressure sits mid-scale
Ashcroft, citing ASME B40.100, recommends that operating pressure fall between 25% and 75% of the scale, with the gauge range about twice the operating pressure so the pointer sits near 12 o'clock. Where pulsation is present, maximum operating pressure should not exceed 50% of full scale. [1]
Ashcroft states that gauges can handle 130–150% of range depending on the range; beyond that, choose a higher range or fit a pressure limiting valve, which shuts off pressure to the gauge when it reaches the set point and resets when pressure falls. [1][2]
As an editorial calculation example only: a line that runs at 6 bar in steady operation sits at 60% of a 0–10 bar gauge and 37.5% of a 0–16 bar gauge, so both are inside 25–75%. If the line pulsates, the 50% limit rules out the 0–10 bar gauge and leaves the 0–16 bar gauge. Check which standard ranges the supplier actually offers.
Give the supplier normal, maximum and minimum pressure, and say whether the line pulsates or sees spikes. A gauge chosen by the maximum pressure alone can read in the bottom quarter of its scale.
02
Protect the gauge from pulsation, vibration and spikes
Ashcroft names six main reasons gauges fail instrument audits: pulsation or vibration, temperature outside limits, pressure spikes, clogging, corrosion and improper installation. As a practical guide, if pulsation or vibration moves the pointer more than about 5% of full scale, corrective action is needed. [2]
Remedies Ashcroft lists include filling the case with silicone, glycerin or halocarbon with an integrated throttle screw; adding pulsation dampeners, throttle screws, needle valves or diaphragm seals; and mounting the gauge remotely on a capillary line away from the vibration source. [2]
Spikes from water hammer, fast valve action or freezing media can dent the pointer, deform or rupture the Bourdon tube or break the gear segment. Ashcroft states that an internal overload stop "typically raises proof pressure by approximately 20%", and that a pressure limiting valve can block flow above full scale. [2]
03
Keep the gauge within its temperature limits
Ashcroft states that "dry gauges are typically rated for use in ambient temperatures below 200°F (93 °C)" and "liquid-filled gauges are typically rated for use in ambient temperatures up to 150 °F (66 °C)"; above these, dials, acrylic windows, gaskets and fill liquid can discolour or degrade. [2]
Temperature also shifts accuracy: as a guide, a gauge calibrated at 68 °F (20 °C) changes by about 0.4% per 25 °F (13.9 °C) away from that temperature. [2]
For hot process media, Ashcroft describes remote mounting on a capillary or a temperature-dissipating siphon between gauge and process. On steam, a coil or pigtail siphon filled with water before installation forms a condensate barrier that lowers the temperature at the gauge and helps against water hammer. [2]
04
Isolate the gauge from clogging, corrosive and hygienic media
Wetted parts must suit the media's composition, concentration and temperature. Where they do not, or where media can build up in the connection, Ashcroft recommends isolating the gauge with a diaphragm seal or isolation ring; a flushing connection lets operators clear the seal, and an isolation ring suits heavy slurries. [2]
In food and beverage lines the seal can also give a cleanable connection. Jianen, for example, describes a tri-clamp diaphragm gauge for brewing and winemaking vessels and filter housings, with a 304 stainless case and 316L diaphragm, which can be removed for cleaning. [3]
Ask the supplier for the diaphragm and wetted materials, the fill liquid inside the seal system, and documents showing they are suitable for your product and cleaning chemicals; a clamp fitting alone does not make a gauge food-contact compliant.
05
Size the dial for the accuracy you need to read
Ashcroft gives dial sizes from 1¼ in to 16 in and states that "typically, the dial arc of a gauge is 270 degrees" in accordance with ASME B40.100. Better accuracy needs finer graduations: for ±0.5% accuracy or better, a dial under 100 mm is not recommended, and "minor dial graduations generally do not exceed twice the accuracy of the gauge". [1]
Larger dials are easier to read from a walkway; installation space can limit the size. Colour zones, dual scales and retroreflective dials are options for marking normal ranges or reading in poor light. [1]
06
Match gauge type and connection to the installation
Basidewt, Edaweld and Jianen between them list stainless and liquid-filled gauges, vacuum, digital and shock-resistant gauges, and a sanitary clamp diaphragm gauge. [4][5][3]
Basidewt lists a liquid-filled gauge with a 304 stainless case and a ¼ NPT lower mount for water systems; Edaweld lists Y-60 gauges with M14×1.5 and Y-100 gauges with M20×1.5 connections, as well as shock-resistant and vacuum gauges. [4][5]
Specify the thread or clamp size, bottom or back mounting, panel or stem mounting, and units on the dial. A thread that matches the existing tapping avoids an adapter that can loosen.
07
Bourdon tube, movement, dial, filled case, connection and seal
Spikes act on the Bourdon tube and vibration wears the movement, so those two rows decide overload protection and damping; materials come from the data sheet of the gauge you order. [2]
Part
Role
Fix in the order
Bourdon tube or sensing element
Deflects under pressure; can deform or rupture under spikes. [2]
Element material, range and overload protection.
Movement
Gears and links that turn the element's motion into pointer travel; worn by vibration. [2]
Movement material and damping.
Pointer and dial
Show the reading on a scale; Ashcroft: "typically, the dial arc of a gauge is 270 degrees". [1]
Dial size, units, scales and colour zones.
Case, window and fill
Protect the movement; liquid fill damps pulsation. [2]
Case and window material, fill liquid and IP rating.
Isolate the gauge from media, heat or pulsation. [2]
Accessory type, materials and fill liquid.
08
Range, dial size, thread, temperature limit and wetted materials for a gauge order
The range row carries the 25–75% rule (at most 50% with pulsation) and the dial row the 100 mm minimum for ±0.5% or better; ingress protection and weight have no published value in the sources, so the supplier must give them. [1]
Field
What it means and published values
Ask the supplier for
Measuring range
Normal pressure at 25–75% of scale, at most 50% with pulsation. [1]
Available ranges and units.
Accuracy class
Better accuracy needs more graduations and a larger dial. [1]
Accuracy and the standard it is stated to.
Dial diameter (mm)
1¼–16 in; not under 100 mm for ±0.5% or better. [1]
Dial size.
Process connection
Thread such as ¼ NPT, M14×1.5 or M20×1.5, or a sanitary clamp. [4][5][3]
Connection type, size and mounting position.
Operating temperature (°C)
Ashcroft: dry gauges "typically rated" for ambient below 93 °C, liquid-filled up to 66 °C. [2]
Ambient and process limits; siphon or remote mount.
12 companies list this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Jianen Sanitary
Manufacturing site to be confirmed for the order
Lists a tri-clamp diaphragm pressure gauge with 304 stainless case and 316L diaphragm for brewing and winemaking vessels.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What range should I choose?
Ashcroft, citing ASME B40.100, recommends operating pressure at 25–75% of scale, with the range about twice the operating pressure, and no more than 50% of full scale where pulsation is present. [1]
Why does my gauge needle shake?
Ashcroft lists "excessive pulsation or vibration" first among six primary causes and suggests corrective action if the pointer moves more than about 5% of full scale, using liquid fill, snubbers, throttle screws, needle valves or remote mounting. [2]
How hot can a liquid-filled gauge get?
Ashcroft states that "liquid-filled gauges are typically rated for use in ambient temperatures up to 150 °F (66 °C)" and dry gauges below 200 °F (93 °C); for hot process media use a siphon or remote mounting. [2]
Sources and what still needs a direct check
Sources checked 2026-10-12. Ashcroft is a gauge manufacturer; its articles cite ASME B40.100, which was not read for this page. Supplier pages describe their own offers.
