GB190620625A - Improvements in and relating to Pneumatic Despatch Tube Apparatus. - Google Patents

Abstract

20,625. Fordyce, E. A. Sept. 17. Pneumatic d i spatch apparatus.- Where suction i s maintained through an outgoing transit-tube A and a return transit-tube K<3>, an atmospheric valve D is opened automatically o n the insertion of the carrier, and is closed automatically under the control of a timing- device. The insertion of a carrier into the outgoing tube opens a valve C at the end of a pipe L which admits atmospheric pressure to the bottom of a cylinder J, the top of which is connected by a pipe K to the suction pipe K<1>. The piston H being accordingly raised, the main atmospheric valve D is opened, and the carrier leaves the subsidiary valve C closed again. Suction through a throttle valve at the bottom of the cylinder then gradually reduces the pressure to let the piston sink and reclose the main valve. Insertion of a carrier into the return tube K<3> at the lid A<4> temporarily restores atmospheric pressure in the outgoing tube A, so that a diaphragm in a pocket L<3> is pressed outwards and opens a valve L<8> at the end of a pipe L<1> which communicates with the bottom of the cylinder. Atmospheric pressure then raises the piston as before.