ACME is a designation, within the context of propane handling, to describe a propane fitting that closes quickly when attached to a pressurized propane system. Although the term "ACME" is not an acronym in this context, fittings with this designation do have a specific acronym called QCC, which stands for "quick closing coupler" connector. ACME fittings are threaded, adaptable with POL (press-o-lite) systems without the need for tools and have a OPD (overflow protection device) blow-off valve to avoid overfilling a tank or canister with pressurized propane.
Type-1 High Flow
Type-1 fittings are designed to attach directly to a canister or tank via threads. The opposite end of the fitting is a ¼-inch threaded outlet that receives a hose for delivery of propane to an exterior high-demand device like a water heater or stove system. Max output on the high-flow type-1 is 200,000 BTUs per hour. All ACME fittings are thermally sensitive, meaning the coupler will close off gas flow automatically if subjected to fire.
Type-1 Low Flow
The low-flow Type-1 utilizes the same 1 5/16-inch ACME threaded fitting with a ¼-inch threaded outlet. The flow is rated to 70,000 BTUs per hour, ideal for gas grills and other low-demand devices like outdoor heaters. The outlet end can attach to a pigtail hose, gauge or other ACME fitting and is thermally sensitive.
When you have a single LP (liquid propane) gas canister, but have two propane appliances, say a stove and a portable heater, the thermally sensitive ACME Extend-A-Stay T will allow you to connect both simultaneously to the gas source. Each appliance's pigtail hose is threaded into one of the T's couplers after the ACME coupler end is attached to the gas canister. The T is also equipped with a high-pressure appliance connection port that receives high-pressure hose threads.
A more basic version of the Extend-A-Stay, the Y splitter, splits gas from a single canister to two hose ports. These low-pressure (10 p.s.i.) hose ports are threaded to pigtail hoses that lead to small LP gas appliances. Different from the Extend-A-Stay, the Y splitter does not have a high-pressure connection port.