Carrier automatic braking system

A pneumatic transmission system, comprising:

• a first station for sending or receiving a carrier;
• a second station for sending or receiving a carrier;
• a transport conduit connected between said first and second stations, wherein said transport conduit is capable of permitting the transfer of a carrier between said first and second stations;
• a supply/exhaust branch connected to said first station such that air can flow between said supply/exhaust branch and said first station, said supply/exhaust branch having an opening which can serve as an air inlet for providing air from the atmosphere through said supply/exhaust branch to the pneumatic transmission system and as an air vent for exhausting air from the pneumatic transmission system through the supply/exhaust branch to the atmosphere;
• a first motor blower positioned within said supply/exhaust branch, wherein said first motor blower is capable of moving a volume of air through said supply/exhaust branch and said transport conduit in a first direction;
• and
• a second motor blower positioned in series with said first motor blower within said supply/exhaust branch, adjacent to and opposite said first motor blower, wherein said second motor blower is capable of moving a volume of air through said supply/exhaust branch and said transport conduit in a second direction which is opposite to said first direction;
• a sensor associate with said transport conduit so that said sensor is capable of detecting the presence of a carrier at a predetermined location in said transport conduit associated with an approach of said carrier to one of said first station and said second station and of generating a control signal in response to a detection of said carrier by said sensor;
• a controller coupled to said sensor and to said first and second motor blowers, wherein said controller activates said first motor blower to move said carrier from one of said first station and said second station to the other one of said first station and said second station and then activates said second motor blower in response to said control signal from said sensor, indicating the detection of said carrier at said predetermined location, while said first motor blower is still activated, to thereby form an air block between said first and second motor blowers to decrease the differential pressure across said carrier and cause said carrier to slow down as it approaches said other one.