Pneumatic transmission system and blower unit therefor

A blower unit adapted for use in a pneumatic transmission system comprising:

• a housing having a first chamber in a first end portion of the housing, a second chamber in a second end portion of the housing, and an intermediate chamber between the first chamber and the second chamber, said first end portion having a first inlet/outlet opening through which air can flow in and out of said housing, and said second end portion having a second inlet/outlet opening through which air can flow in and out of said housing;
• a first blower disposed within the housing such that the first blower can move air from the first chamber to the intermediate chamber;
• a first bypass path providing a path for air to flow between the first chamber and the intermediate chamber;
• and
• a first blocking member for substantially blocking the first bypass path while the first blower is moving air from the first chamber to the intermediate chamber;
• a second blower disposed within said housing such that the second blower can move air from the second chamber to the intermediate chamber;
• a second bypass path providing a path for air to flow between the second chamber and the intermediate chamber;
• and
• a second blocking member for substantially blocking the second bypass path while the second blower is moving air from the second chamber to the intermediate chamber;
• wherein said first and second blowers are mounted in said housing such that said second blower is downstream of said first blower when air is flowing from said first inlet/outlet opening to said second inlet/outlet opening and said first blower is downstream of said second blower when air is flowing from said second inlet/outlet opening to said first inlet/outlet opening.

A pneumatic transmission system, comprising:

• a first station for sending or receiving a carrier;
• a second station for sending or receiving the carrier;
• a transport conduit which is connected between the first station and the second station, wherein the transport conduit permits a transfer of the carrier between the first station and the second station;
• a blower unit comprising:
• a housing having first and second inlet/outlet openings through which air can flow;
• a first blower, disposed within said housing, for moving a volume of air from said first inlet/outlet opening to said second inlet/outlet opening;
• a first bypass path, disposed within said housing, through which air can flow from said second inlet/outlet opening to said first inlet/outlet opening without flowing through said first blower;
• and
• a first valve element, disposed in said first bypass path, for substantially blocking a flow of air through said first bypass path when said first blower is active,
• wherein said blower unit is in communication with said transport conduit such that air can flow from the first inlet/outlet opening to the transport conduit and from the transport conduit to the first inlet/outlet opening;
• a second blower, disposed within said housing, for moving a volume of air from said second inlet/outlet opening to said first inlet/outlet opening;
• a second bypass path, disposed within said housing, through which air can flow from said first inlet/outlet opening to said second inlet/outlet opening without flowing through said second blower;
• and
• a second valve element, disposed in said second bypass path, for substantially blocking a flow of air through said second bypass path when said second blower is active;
• wherein said first and second blowers are mounted in said housing such that said second blower is downstream of said first blower when air is flowing from said first inlet/outlet opening to said second inlet/outlet opening and said first blower is downstream of said second blower when air is flowing from said second inlet/outlet opening to said first inlet/outlet opening.