Pressure regulating unit

A pressure regulating unit for providing two different controlled pressures, said unit comprising

• a block made of a single piece of metal and having a mounting structure integrally provided thereon and a gas flow passage provided therein, said gas flow passage having a high pressure inlet for connection to a source of high-pressure gas having varying pressure and a first port for connection to a pressure regulator, and
• first, second and third pressure regulators that are supported by said mounting structure, said first regulator having a gas inlet communicating with said first port, said first regulator being a step-down regulator for supplying a substantially constant pressure gas to said second and third pressure regulators,
• said first, second, and third pressure regulators including pressure adjusters that have been permanently fixed in place after adjustment to a desired setting, said block carrying no more than a single pressure gauge, said single pressure gauge communicating with said first port.