Pneumatic dispatchxcarrier-separating d device
US 3236475 A
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Description (OCR text may contain errors)
Feb. 22, 1966 MACH ETAL 3,236,475
PNEUMATIC DISPA'ICH-CARRIER-SEPARATING DEVICE Filed Sept. 9, 1963 Fl'g- 2 Fig. 7
INVENTORS HORST MACH HAN$JOACHIM PTER FRANZ L/PP/TZ United States Patent 3,236,475 PNEUMATIC DISPATCH-CARRIER- SEPARATING DEVICE Horst Mach, Hans-Joachim Peter, and Franz Lippitz, Berlin, Germany, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Sept. 9, 1963, Ser. No. 307,563 Claims priority, application Germany, Oct. 8, 1962, St 19,821 8 Claims. (Cl. 243-1) The invention relates to an arrangement in pneumatic tube systems for separating the lead carrier of a carrier train at a receiving station of the system or at such a point in the system where it is desired to stop the carriers and to dispatch them individually, for example in order to determine their spacing or to set their route in some other manner.
Our invention refers in particular to a pneumatic carrier-separating arrangement which slows down the carrier train by regulating the compressed air, separates the lead carrier from the train, and then holds it for forwarding from there. Known separating arrangements require a relatively high investment in adjustable valves, shut-off valves, tubing, drive contacts, and other equipment which increase the cost of the system considerably. Such known arrangements consist of branches, linked by intermediate lines, at three successive points of the main tube. The carrier train is intercepted between the first and the third branch and the carrier to be separated is stopped between the second and the third branch and further dispatched from there, whereupon the next lead carrier takes its place. Since, once the carriers enter that section of the tube system provided with branches, the compressed air can no longer act on them, the carrier train is slowed down.
Our invention concerns a pneumatic carrier-separating device for pneumatic tube systems whose main tube has branches connected by intermediate lines at three successive points, in which case the carrier train to be separated is intercepted between the first and the third branch and the lead carrier to be separated is stopped between the second and third branch and further dispatched from there. However, the drawback of the known arrangement, that is, the high cost of such a system which also increases maintenance and reduces reliability of operation is eliminated according to our invention. This is done by arranging between the second and third branch, alternately, the input or output of a blower or of a similar pressure/vacuum source and a valve flap in the main tube at the point of the third branch. The first branch serves to capture the initial air. The blowers blast may be reversible and such reversal is controlled by a contact in the main tube actuated by a carrier.
The invention and its mode of operation will now be described with the aid of the accompanying drawings, in which:
FIG. 1 shows schematically a pneumatic tube system with carrier-separating device according to our invention; and
FIG. 2 shows a modified embodiment of FIG. 1.
Carriers in main tube 1 travel in the direction of the arrow shown in main tube 1. The carriers first reach braking section I and immediately thereafter lock sections II, III. At the start of section I, branch 2 captures the initial air and may have a back-pressure valve 3 and an adjustable butterfly valve 4a. In the example according to FIG. 1, branch 2 is connected to blower G. Branch 5 at the start of lock section II branches off from main tube 1 and has an adjustable butterfly valve 4b, connected to the same side of blower G as is branch 2. The other 3,236,475 Patented Feb. 22, 1966 side of blower G connects via branch tube 6 to the end of lock section III in main tube 1. Valve flap 7 is between II and III and can be opened in the direction of travel only by a reversed air current and otherwise remains closed due to the different air pressures. Valve flap 7 can also be held shut by a spring. Another valve flap 8 may be arranged beyond branch 6 to isolate the separating sections from the rest of the system. Main tube contact 9 serves to indicate that a carrier is in front of valve flap 7.
Such an arrangement operates as follows:
An approaching carrier or carrier train moves in the direction of the arrow into braking section I, which is shown as an upward curving are but may also be a straight line. The carrier train reaches branch 5. Butterfly valves 4a and 4b are so adjusted that the carriers entering section -I are braked so that the lead carrier arrives at flap valve 7 at a very low velocity. Valve flap 7 is spaced the length of one carrier away from branch 5. The air driving the carriers is split up by branches 1 and 2, so that a substantial portion travels through branch 2, and another portion through branch 5, to blower G. The arriving carriers do not have enough kinetic energy to open valve flap 7.
When there is a carrier in front of valve flap 7, it causes main tube contact 9 to operate. If the lead carrier of the train is to be further dispatched, the direction of the airflow is reversed. Whereas the air was previously flowing in the direction of heavy arrows 10 and 11, once reversed it flows in the direction of broken arrows :12 and 13. Back-pressure valve 3 prevents the air from escaping through branch 2. The full air current is thus directed through branch 5 and strikes between the lead carrier and the carriers behind it, pushing the lead carrier through valve flap 7. Valve flap 8 prevents any inflow of air from the tube section ahead. With proper air conditions, it is possible to eliminate flap valve 8. A timing circuit now stops the reversal of airflow and the lead carrier in front of valve 8 can continue on its way, while the rest of the carrier train is so advanced that another single carrier is in front of valve 7, whereupon the process repeats itself.
It is noteworthy that the only control such a carrierseparating device requires is the reversal of the blowers airflow and the removal of such a reversal by means of a timing circuit. Flap valves 7 and 8 and backpressure valve 3 require no external control, and butterfly valves 4a and 4b are permanently set.
FIG. 2 shows a modification of the embodiment according to FIG. 1. Branch 2 with butterfly valve 4a is under vacuum or at atmospheric pressure, while another branch 14 with a butterfly valve 15' behind valve flap 8 is at atmospheric or higher pressure. The advantage of this arrangement is that the carriers in the main tube, when passing beyond the locks, are not stopped by the process of separation as in the configuration of FIG. 1 but retain a portion of their original speed in the conveying section due to the combined action of blower 16 in branch 2 and the source of higher pressure in branch 14. In such an arrangement, flap 8 is necessary to prevent the higher pressure in the forwarding tube from having access to section III of the lock. Otherwise, this system functions similarly to that of FIG. 1.
While we have described the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention as set forth in the accompanying claims.
1. An arrangement for separating a train of carriers propelled by an air-pressure differential in the forwarding tube of a pneumatic tube system comprising: first, second, and third branch tubes positioned so that carriers arrive at said first branch tube before arriving successively at said second and third branch tubes, and at said second branch tube before said third branch tube, said first branch operating to relieve the pressure differential across the lead carrier of said train; a reversible blower connected between said second and third branch tubes, control means cooperating with air propelled by said blower in a first direction for stopping arriving carriers between said second and third tubes, and cooperating with air propelled by said blower in a direction opposite to said first direction for moving the lead carrier of the stopped carriers between said second and third tubes whereby only said lead carrier is in a position for further conveyance in said forwarding tube beyond the intersection of said third branch tube with said forwarding tube.
2. An arrangement according to claim 1 further comprising a fourth branch tube connected to said forwarding tube beyond said third branch tube relative to the direction of travel of the carriers, a blower other than said reversible blower connected between said first and fourth branch tubes, and a valve fla-p in said forwarding tube between said third and fourth branch tubes.
3. An arrangement according to claim 1 wherein said reversible blower is connected to said first branch tube via said second branch tube.
4. An arrangement according to claim 3 wherein said control means comprises a first valve flap positioned in said forwarding tube between said second and third branch tubes about one carrier length of the carriers used in the pneumatic tube system away from said second branch tube.
5. An arrangement according to claim 4 wherein said control means further comprises a check valve in said first branch tube for preventing air from said reversible blower, opposite to the air flow in said pneumatic tube system, from reaching said pneumatic tube system.
6. An arrangement according to claim 5 wherein said control means further comprises sensing means in said forwarding tube positioned between said second branch tube and said first valve flap for indicating the presence of a carrier between said second branch tube and said first valve flap.
7. An arrangement according to claim 6 wherein said control means further comprises a second valve flap positioned beyond said third branch tube in the direction of travel of said carriers for pneumatically separating said isolating arrangement from the pneumatic tube system beyond said third branch tube when desired.
8. An arrangement according to claim 1 wherein said forwarding tube is disposed in a horizontal position at the point of connection with said first branch tube and in a vertical position at the points of connection with said second and third branch tubes.
No references cited.
SAMUEL F COLEMAN, Primary Examiner.
ANDRES H. NIELSEN, Examiner.