ALEXANDRIA, Va., May 5 -- United States Patent no. 12,618,407, issued on May 5, was assigned to ELIVAC Co. LTD. (Shanghai), Ching Link Consultant Co. Ltd (Shanghai) and ELIVAC INC (Salisbury, Md.).
"Connecting ring of a root vacuum pump" was invented by Raymond Zhou Shaw (Shanghai).
According to the abstract* released by the U.S. Patent & Trademark Office: "A connecting ring of a root vacuum pump is provided. The connecting ring is installed in at least one end portion of a casing of a root vacuum pump for enlarging an effective volume of the casing. The connecting ring includes a frame having a hollow circular structure and being match to a shape of an end portion of the casing; a front end of the frame being formed with a front flange; ...