This video demonstrates a 0 to 1000psi electronic pressure regulator providing the pilot control signal to an Equilibar precision back pressure regulator. The Equilibar back pressure regulator is seen in the video as the 70mm diameter round stainless steel device that has the digital pressure indicator connected to it. The LF series « low flow » regulator by Equilibar is shown. The LF back pressure regulator uses a flexible diaphragm membrane as the only moving part. This diaphragm operates in a nearly frictionless manner to control the inlet pressure in a precise one to one relationship to the reference pressure that is applied on the pilot port. This pilot reference pressure may be provided by a manually adjusted regulator or by an electronically controlled regulator. The video shows an electronic pressure regulator providing the pilot pressure. The high pressure electronic regulator used in the video is a Proportion-Air model GX. The GX is the bronze color valve that is bracket mounted to the aluminum extrusion framework of the test bench. The GX electronic regulator can control high pressure compressed gas based on an electronic command signal. The GX used in the video is calibrated 4-20mA = 0 to 1000psi. The GX electronic pressure regulator consists of two high pressure solenoid valves, a stainless steel pressure sensor, and a control circuit, all mounted inside a rugged IP65 / NEMA4x anodized aluminum protective housing. The GX operates by comparing the user provided command signal to the signal from its internal pressure sensor. The GX control circuit them actuates the inlet solenoid valve to allow more compressed gas into the system in order to increase the pressure, or the circuit actuates the exhaust solenoid valve to decrease the system pressure. The GX circuit will continue actuating the appropriate solenoid valve until the two signals match. The GX series recently replaced the similar older GP series. The primary difference is that the GP used digital ON/OFF solenoid valves while the newer GX uses solenoid valves which respond proportionally. For this video a 4-20mA command reference signal was sent to the GX electronic regulator by a Fluke 787 Process Meter. The Fluke 787 is a handy product that allows you to manually input a mA signal between 0 and 24 mA or you can use the Fluke’s automated ramping or stepping functions. In the video the GX electronic regulator is sent a 4-20mA command signal which causes the GX to control the pressure linearly and proportionally between 0 and 1000psi. The GX draws its supply pressure from a bottle of compressed nitrogen (seen over my left shoulder) that is set at 1100psi. The controlled output pressure of the GX is then supplied through a length of high pressure black hose to the pilot port of the LF back pressure regulator. The LF series back pressure regulator then controls its inlet port pressure in a precise 1:1 relationship to the pressure applied on its pilot port by the GX. In the video you see the command to the GX being set and you can hear the GX regulator modulating its solenoid valves to adjust the pressure. The pressure being controlled on the LF series back pressure regulator’s inlet port is seen on the WIKA brand digital pressure indicator. After the electronic command is set to the GX you can watch on the digital pressure indicator how the pressure builds on the LF inlet port and is ultimately controlled at the same pressure as is applied to the pilot port by the GX electronic regulator. This is all done open loop and there is no control other than the command signal sent to the GX. One advantage of this is that the sensitive electronic GX regulator handles only clean dry bottled gas while the LF back pressure regulator handles the system media. The LF back pressure regulator is available in stainless steel, Hastelloy, Zirconium, and Titanium body materials with PTFE, PEEK, FKKM, FKM, and other materials available as soft goods options. The LF is particularly suited to catalysis research reactor applications where mixed gas and liquid phases are used, where temperatures may be high, and/or where the media may contain aggressive chemicals.