Hydrogen filling stations need a variety of high-quality, hydrogen-compatible measuring instruments for storing, compressing, cooling, and dispensing the fuel.
This article is a continuation of “Hydrogen Fueling Stations Need Specialized Instrument Solutions.”
A station’s pressure transmitters, pressure switches, pressure gauges, instrument valves, thermometers, thermowells, and temperature transmitters must be able to withstand high pressures, low temperatures, and hydrogen permeation.
In addition, the pressure and temperature transmitters need to be designed as intrinsically safe or explosion-proof for use in hazardous areas with the required approvals. Depending on a station’s setup, there are up to 20 installations where hazardous area transmitters are used.
Pressure Instruments for Hydrogen Fueling Stations
E-10
IS-3
Pressure transmitters
WIKA offers two pressure transmitters for hydrogen fueling stations:
- IS-3 intrinsically safe pressure transmitter
- E-10 explosion-proof and flameproof pressure transmitter
Both models have internationally recognized hazardous area approvals. When ordered specifically for hydrogen service, these pressure transmitters come with a fully welded Elgiloy® diaphragm, which – compared to common 316L stainless steel – provides greater resistance to hydrogen embrittlement and permeation. For an even greater resistance to hydrogen permeation, use a gold-plated flush diaphragm seal with either the IS-3 or E-10; this combination is the ultimate solution for applications that require a high degree of safety and longevity.
Depending on the design of your hazardous area protection concept, both pressure transmitter models are ideal for hydrogen fuel station equipment and control systems such as storage tanks, compressors, pumps, chillers, heat exchangers, evaporators, and dispensers.
232.34/233.34
Pressure gauges
Found throughout a hydrogen fueling station, pressure gauges provide reliable local indication of the pressure between each stage of the fueling process. Typical applications include high-pressure and low-pressure storage, multistage compression, and control cabinets. Mechanical gauges also play a crucial role during maintenance work and power outages.
Models 232.30/233.30 and 232.34/233.34 process-grade pressure gauges are made of 316L stainless steel wetted parts to resist hydrogen permeation and embrittlement. In addition, these Bourdon tube pressure gauges feature a safety case to protect people standing in front of the instruments. The design consists of two special features: a solid front wall placed behind the dial, and a blowout plate on the back side that is released from the case in the event of excessive internal pressure or a Bourdon tube rupture.
PXA
Pressure switches
Model PXA is a high-quality mechanical pressure switch developed especially for safety-critical applications. Its compact design and flameproof enclosure make the PXA ideal for control panels in hydrogen fueling stations. All wetted parts are made of hydrogen-compatible 316L stainless steel, and is available with silver- or gold-plated contacts in SPDT or DPDT configuration and micro-switch electrical ratings of 5 amps at 250 VAC or 24 VDC.
Other applications for this miniature pressure switch include the monitoring and control of hydrogen storage tanks, buffer tanks, multistage compressors, and pump systems.
Instrument valves
IV20
Instrument valves are designed to isolate the measuring instrument from the hydrogen gas so that it can be removed for calibration, repair, replacement, and other services. For added safety, the model IV20 block-and-bleed valve contains an additional needle valve to safely vent trapped gas before removing the instrument.
WIKA has a complete portfolio of durable 316 stainless steel needle valve and multiport valves, high-pressure needle valves, and manifold valves that are suitable for hydrogen use. As an option, we offer the professional assembly of valves and pressure instruments into a ready-to-install solution. To ensure safety and performance, the complete assembly undergoes an additional leak test.
TW10
TR10
Temperature Instruments for Hydrogen Fueling Stations
Temperature sensors and thermowells
Temperature measurement is critical to the safe operation and processing of the hydrogen gas prior to dispensing it into a vehicle’s fuel tank. Typical temperature measuring points for monitoring and control include storage tanks, evaporators, compressors, and chillers.
Model TR10 measures temperatures from −320 to 1,112°F (−196 to 600 °C) using a Pt100 or Pt1000 sensor. This resistance thermometer has a heavy-duty 316L stainless steel probe that can be installed directly into the process without a thermowell, providing very fast response times and high accuracy. For an extra level of protection, pair the RTD with a hydrogen-compatible thermowell like the solid-machined TW10 made of 316L stainless steel with full-penetration welding.
T32 connected to a RTD
T15
In addition, the TR10 can be configured with various mounting heads, including ones with digital displays, and are rated for use in hazardous areas. For optional outputs signals, the RTD can be paired to our T15 digital temperature transmitter with 4-20 mA output or the T32 digital temperature transmitter with HART® communication, which is available in SIL-certified versions.
Smart Sensors for Hydrogen Storage, Compression, and Dispensing
WIKA offers high-quality measuring solutions for almost every hydrogen application, from conventional production and water electrolysis to fuel cells and hydrogen refueling stations. We have specialists who are well versed in the entire hydrogen value chain for various industries. They look forward to helping your company find and incorporate the right measuring instruments to safely and reliably control your next-generation hydrogen equipment.
Products mentioned in this article:
• IS-3 intrinsically safe pressure transmitter
• E-10 explosion-proof and flameproof pressure transmitter
• 232.30/233.30 process-grade pressure gauges
• 232.34/233.34 process-grade pressure gauges
• PXA mechanical pressure switch
• IV20 block-and-bleed valve
• TR10 series resistance thermometer, industrial assembly
• TW10 solid-machined thermowell with flange
• T15 digital temperature transmitter with 4-20 mA output
• T32 digital temperature transmitter with HART® communication