{"id":14088,"date":"2021-02-24T11:02:46","date_gmt":"2021-02-24T16:02:46","guid":{"rendered":"https:\/\/blog.wika.com\/us\/\/?p=14088"},"modified":"2025-06-11T08:31:37","modified_gmt":"2025-06-11T13:31:37","slug":"direct-drive-pressure-gauges-aerospace-military-oxygen-systems","status":"publish","type":"post","link":"https:\/\/blog.wika.com\/us\/applications\/direct-drive-pressure-gauges-aerospace-military-oxygen-systems\/","title":{"rendered":"WIKA Customizes Direct Drive Pressure Gauges for Aerospace and Military Oxygen Systems"},"content":{"rendered":"

With only one moving part, direct drive pressure gauges are extremely compact, rugged, and reliable. These characteristics are what make them ideal for use in safety-critical applications, such as oxygen systems found in airplanes and submarines. <\/strong><\/p>\n

Traditional Pressure Gauges vs Direct Drive Gauges<\/h2>\n

The traditional Bourdon tube gauge<\/a> offers many advantages: good accuracy, low cost, adaptability for electrical outputs, and wide operating range \u2013 from vacuum to an upper limit of around 20,000 psi (1,600 bar). That\u2019s why even though the technology dates from the mid-1800s, this type of mechanical pressure gauge is still found in a myriad of industrial applications today.<\/p>\n

However, the traditional C-shaped Bourdon gauge has several moving parts: spring, segment and pinion gears, linkage, pivot, and lever. More parts mean greater potential for wear and gauge failure<\/a> in applications with extreme vibration and pulsation. What\u2019s more, all those components take up space. The smallest Bourdon tube gauge has a nominal size of 1\u00bd” (40 mm), often too large for applications like portable gas cylinders.<\/p>\n

Out of these drawbacks came the direct drive gauge.<\/p>\n

Measuring Principle of the Direct Drive Gauge<\/h2>\n\n
\"Direct

A direct drive gauge has either a spiral (left) or helical Bourdon tube made of the superalloy Inconel\u00ae X-750.<\/p><\/div>\n \n

A direct drive gauge has a Bourdon tube, but it is in a spiral or a helical (corkscrew) formation instead of the traditional C shape. The coil, made of the corrosion-resistant superalloy Inconel\u00ae<\/sup> X-750, expands under pressurization. The pointer shaft, which is attached directly to the spiral or helical tube, moves right or left as the coiled tube expands or contracts. See this video<\/a> for a detailed explanation of how a direct drive gauge works.<\/p>\n

Spiral is by far the more popular pressure element, as it measures lower pressures and uses less of the superalloy. A higher maximum pressure and, thus, more material equal a higher cost for direct drive gauges with a helical Bourdon tube.<\/p>\n

Advantages of Direct Drive Gauges: One Moving Part<\/h2>\n