PNEUMATIC TUBE SYSTEM

• US 3,711,038 A
• Filed: 09/14/1970
• Issued: 01/16/1973
• Est. Priority Date: 09/14/1970
• Status: Expired due to Term

• Current Assignee: Wilbur M Van Otteren
• Original Assignee: Wilbur M Van Otteren
• Inventors: Van Otteren, Wilbur M.
• Primary Examiner(s): Blunk, Evon C.
• Assistant Examiner(s): Maffei, Merle F.
• Application Number:
  US05/071,793
• Time in Patent Office: 855 Days
• Field of Search: 243/1,2,5,7,19,38,16
• US Class Current: 406/19
• CPC Class Codes: B65G 51/04 Conveying the articles in carriers having a cross-section approximating that of the pipe or tube; Tube mail systems

Abstract

In a pneumatic tube transport system the direction of air pressure from a single blower is reversed to slow down a carrier at a terminal station. Controls automatically operate an air shifter to switch the blower connection from pressure to vacuum and then to a low positive pressure as the carrier approaches a terminal station and operates oppositely for reverse carrier travel. The invention is particularly adapted for large carrier systems and includes improved station structure for insuring carrier closure and locking.

Claims

1. In a pneumatic tube system having a sealed tube extending between a first station and at least one terminal station, an air compressor having an inlet and outlet and shifter means selectively connecting inlet or outlet of said compressor to said first station, and a carrier adapted to fit said tube for movement by air pressure or vacuum between said stations, the improvement comprising a metering valve connecting said shifter and first station and movable between a normal open position to an operated partially closed position for metering the flow of air between said first station and shifter, signalling means communicating with said tube and spaced from each terminal station toward said first station and signalling passage of a carrier through the tube toward the terminal station, and control means actuated by said signalling means and reversing said shifter means to reverse the flow of air for an adjustable time period to slow down the carrier and then returning the shifter means to original position and moving said metering valve to operated partially closed position to slowly move the carrier into the terminal station.

2. The improved system of claim 1 further defined by a start switch at each station and switching means in each station operated by the presence of a carrier therein, said start switch and switching means being serially connected whereby air pressure or vacuum to move the carrier from the station can only be applied by operation of both the start switch and switching means.

3. The improvement of claim 2 further defined by said shifter means including a vane movable between a first position connecting the compressor outlet to said first station and the compressor inlet to atmosphere and a second position connecting the compressor inlet to said first station and the compressor outlet to atmosphere, solenoid means for moving the air shifter vane between said first and second positions, relay means connected for operation by said combination of start switch and switching means and having contacts connected to control energization of said solenoid means.

4. A method of moving a carrier from a first station to a second station through a sealed tube extending between the stations and in which the carrier slidably fits, comprising the steps of a. applying a substantial positive air pressure to the tube behind the carrier at the first station to urge the carrier through the tube toward the second station, b. sensing passage of the carrier through the tube toward the second station at a short predetermined distance from the second station, c. automatically terminating application of air pressure in response to sensing of passage of said carrier and in further response to passage of said carrier toward said second station applying a vacuum to the tube at the first station for a predetermined period of tIme, and d. terminating the application of vacuum to the tube a predetermined time after application thereof in step (c) so that the carrier moves slowly into the second station.

5. The method of claim 4 further defined by maintaining application of the vacuum to the tube until the carrier substantially stops in the tube and then, after terminating the vacuum, applying to the tube at the first station a low positive air pressure to slowly move the carrier into the second station.