CA1055782A - Transport system with blocking valve control - Google Patents

Abstract

TRANSPORT SYSTEM WITH BLOCKING VALVE CONTROL
ABSTRACT
A pump which generates pressurized air flow in a pipeline to sweep wheeled vehicles along with the air flow is provided with a flow control mechanism. First and second blocking valves which normally prevent reverse flow of air in the pipeline but which can alternately swing open to allow a vehicle to pass are automatically moved between open and closed positions by altering the pressure differential acting on the valves. The valves are urged to the open position and air flow control valves associated with the pump alternately directs air against the back of the valves in response to the position of a vehicle to sequentially operate the valves to move the vehicle through the pump.

Description

~5iS~32 TRANSPORT SYSTEM WITH BLOCKING_VALVE CONI'ROI.
BACKGROUND OF THE INVENTION
This invention relates to transport systems such as those disclosed in United States Patents 4,017,039 of April 12, 1977; 3,724,691 of April 3, 1973; 3,797,405 of March 19, 1975;
and 3,881,A25 of May 6, 1975.
In the above systems, a wheel-supported vehicle or a train of them moves through a conduit system through which ! air is pumped. Each vehicle incompletely Eills the cross section of the conduit system and presents a high coefficient of drag j 10 with respect to the air being pumped through the conduit system.
l ,- The air ~low is maintained at a high mass rate of flow and vehicles are swept along by this flow of air.
In the development of these systems, several types of air pumps were employed. One type, as disclosed in patent 3,797,405, may be regarded as a jet type of pump in which air is withdrawn from the conduit,system and discharged back into the conduit system through what is effectively a restriction or nozzle, the resultant high velocity of the jet stream discharge being partlally converted, downstream of the discharge region, 20, into a pressu're component which creates or maintains the requisite momentum for the high mass rate of flow. Although this type ,of pump system is low cost and reliable, the amount of air which can be withdrawn from the conduit system and then reirltroduce thereinto under high. velocity, is limited to a fraction of the total flow in the conduit system in order to avoid a "dead spot" or any tendency for reverse flow in the conduit system ~ between the regions of air withdrawal and reintroduc:tion by the pump. Consequently, in order to provide a.system having hlgh total energy input with this type of pump, a large number of them are required in series along the pipeline or conduit ~557~2 l system.
Subsequent developments involved the use of pumps _ which develop the requisite air momentum not by a high velocity, jet stream discharye but by directly discharging the high mass i rate of flow into the conduit system, thereby creating a tendency ¦ for the air to flow reversely or in upstream direction from the region of introduction. The air inducted by the pump may either be withdrawn from the conduit system or it may be ambient air, depending upon whether the pump is employed as a booster along the conduit system or whether it operates as an end-of-line pump. In any event, some physical obstruction is required ¦ immediately upstream from the region of air introduction to prevent air reversal through the conduit. In Patent No. 3,881,425, ¦ the vehicles themselves are used for this purpose and in order ¦ to move the vehicles to a point beyond or downstream of the ¦ region of air introduction or discharge in order to get them moving within the conduit system, a mechanical drive unit may be employed. Although- this type of system is very efficient, it does require the complexity and disadvantage of a mechanical i 20 drive unit of some kind and also lmposes a program of vehicle -movement through the system.
- In order to eliminate the constraints of the immediately foregoing systems, a further pump arrangement was developed, as disclosed in Patent No. 4l017~039. In such systems, the physical obstruction required to prevent any significant re-verse flow of air is provided by an overhead-suspended, counter-balanced flapper valve which is responsive to the phenomenon of an approaching vehicle automatically to swing upwardly out of the way of the vehicle, allowing it to pass therebeyond and back into the mainstream of the moving air mass. The valve closes automatically behind the vehicle or train.

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1 The present invention is directed to systems using two valves which allow still greater pressure differentials to be employed. While Patent No. 1,753,987 describes a system using two valves for moving a postal capsule, such a system is unsatisfactory for moving wheeled vehicles.
~RIEF SUMMARY OF THE INVENTION
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The present invenkion is directed to a transport system in which two overhead-suspended flapper valves are em-ployed to provide the physical obstruction necessary to prevent any subs~antial reverse flow of air upstream from the region of air discharge of a pressure pump. In contrast to my prior arrangements, the pressure differential change across the valves which is the phenomenon by means of which the valves are swung upwardly to clear a vehicle is not created by an entrapped mass of air ahead of a ~ehicle, but is instead created by a pump-induced air flow change itsel~.
Basically, the present system employs two overhead-suspended, openly urged valves upstream from the region of the pressuxe pump discharge into the pipeline or conduit system, the air flow being alternately directed against the ~alves such that a pressure dif~erential is developed across the valves to alternateIy close the valves in combination with sensor means responsive to the approach of an incoming vehicle or train~ for causing an alteration in air flow which changes the pressure *if~erential across the valves which opens and closes the irs~ and second valves alternateIy. The pump or air-displacing means may be a hoos~er type pump which withdraws the full system ~air from one region of the conduit system and discharges it back into a second region of the conduit system or ik may be an end-of-line type o~ pump or air displacing means in which ambient air is inducted and pressurized air is discharged into -~ the pipeline.

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1 The air displacing means includes two discharge outlets connec~ed to spaced regions of the pipeline, each for directing air against the back of and actuating a swingable flapper valve.
One or the other of these discharge outlets is blocked by a suitable air flow control valve and the two are linked together by a common actuating mechanism such that in a normal position, one outlet discharges into the pipeline while the other is blocked but wherein this situation is reversed in response to the detection of an approaching vehicleO Auxiliary pump means having an inlet connected to the pipeline between the first and second valves may be provided to further assist in the movement of vehicles through the pump.

Figure 1 is a diagrammatic illustration of an embodiment of the invention and illustrating an end-of-line system;
Figure 2 is a-view similar to Figure 1 but showing the control means in altered positions;
Figure 3 is a view similar to Figures 1 and 2 but showing the operation after the vehicle passes the pump section;
Figure 4 is a diagrammatic view illustrating control valve actuation for the embodiment of Figure l;
Figure 5 is a diagrammatic vi.ew illustrating another embodiment of the invention~ this time again in an end-o~-line configùration;
Figures~6 and 7 are views similar to Figure 5 but illustrating thP pa~sage o~ the vehicle through the system;
and Figure 8 is a diagrammatic view of a further embodi-ment of the invention.

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With reference at this time to Figure 1 in particular, th reference character 10 indicates in general a continuous ' ' .~S57~

l pipeline or conduit system through which wheeled vehicles pass freely in the direction of the arrow indicated by the reference character 12. Air-displacing means 14 which may take any con-venient conventional ~orm is provid~d with an inlet 16 through which air is inducted and having an outlet 20. The device 14 is adapted to displace air at a high mass rate of flow and at a pressure differential between the inlet and outlet thereof to establish a high mass rate air f:Low of air through the pipe-line lO as is disclosed in my aforesaid prior patent 3,797,405 A wheeled vehicle v is shown approaching the pump station and, as will be understood from my prior disclosures mentioned hereinabove, this vehicle only incompletely fills the cross section of the pipeline 10 and is so shaped as to have a high coefficient of drag with respect to the air flowing through the system so that even though the air flows around and past the vehicle, the vehicle is swept along by the high mass rate flow o~ air sweeping through the system.
Figures 1, 2 and 3 are intended to illustrate a basic prin~iple of this invention, namely, th~ control of air flow generated by the pump means 14 so as to allow first valve 22 and second valve 24 to move from a closed position to an out-of the-way open position allowing unimpeded movement of the vehicle v therepast without in the process requiring eikher the momentum o~ the vehicle to ~uild up air pressure ahead of it in order to open the valves or the vehicle to contact ~he valves 22 and 24. To this end, air ahead of the vehicle v passes outwardly through a vent 18 to prevent pressure build-up such as would slow the vehicle.
The overhead-suspended flapper valves 22 and 24 are 3a provided in order to prevent reverse flow of air from the pump outlet 20 back in the direction of the approaching vehicle.

- Valve 22 is supported ~rom a pivot axis 26 and is connected ' " ' ~55~7~2 1 to an arm 28, which is illustrated only in Figure 2 ~or clarity, to which counterbalanciny means such as a weight or a spring is attached, here shown as weight 17, for countexbalancing the valve 22 normally to urge it or to allow it easily to swing to an open position when the pressure differential created normally by the pump means is altered Similarly, valve 24 is supported from pivot axis 27 and is connected to an arm 29 to which counterbalancing means such as a weight or spring, here shown as spring l9 outside said conduit, is attached for counterbalancing the valve 24 and urging valve 24 to swing to an open position. The edge~ of both valves 22 and 24 are molded to match the contour of the inside pipe wall in order to seal against the inside of the pipeline lO when moved to the closed position.
Referring to Figure 1, an end-of-line type of pump station is illustrated in which air flow control means is associated with the pump 14 for alternately directiny air against the backs 23 and 25, respectively, of valves 22 and 24 to control their opening and closing relative to the position of vehicle v. The outlet 20 of the pump 14 has two branches, the first branch 48 discharges into the region 50 of the pipeline lO
and the second branch 42 discharging into the region 44 of the pipeline lO. It is noted that regions 50 and 44 open into the top of pipeline lO and therefore do not interfere with the wheeIs on vehicle v~ It is also noked that regions 50 and 44 are positioned to direct air on the back of valves 22 and 24, respectively, for closing said valves by establishing a pressure differential across the valves which alternately maintain them in the closed position thereby preventing any substantial reVer;e flow of air past the valves 22 and 24.
Flow of air from the pump 14 alternately to branch 48 and 42 is controlled by any suitable means such as butterfly valves : . ,; ~ ~ , : , . . .
: , :

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l 56 and 58, respectively. As shown in Figure l, butter~ly valve 56 is blocking branch 48 preventing air ~rom pump 14 flowing into region 50 and therefore first valve 22 is urged to an open position by its counterbalancing means 17. However, butter-fly valve 58 i~ in the open position allowing air to flow from pump 14 through branch 42 and into :region 44 and against the back 25 of valve 24 thereby moving valve 24 to khe closed position.
Therefore, air flows from the pump :l4 through branch 42 and past closed valve 24 downstream in the pipeline lO to move any vehicles v in the line lO downstream of valve 24 through the pipeline lO, but yet prevents reverse flow o air through valve 24.
The pipeline end section 54 is pref~rably downwardly inclined to let the vehicles v roll by gravity into the pipeline and past the open valve 22 and into the section 46 of the pipe-line between the regions 44 and 50. In order to prevent air baing trapped ahead of the vehicle and between closed valve 24, an air vent 18 is provided. ~s soon as the vehicle approaches s~ction 46, as in Figure 2, a detector or sensor 30 positioned ~ therein operates a suitable actuating means, which will be more fully described hereinafter, to operate the two valves 56 and 58 from the posi~ions shown in Figure 1 to the positions shown in Figure 2. Thus, now all of the air displaced by the device 20 is diverted into the pipeline 10 through the branch 48, reverse flow escape thexeof being prevented by the valve 22 which has been closed by th~ air flow through branch 48 and is now held positively in the closed position. At the same time, the pressure differential which existed across the valve 24 in Figure 1 which tended to maintain it in the closed position is now changed such that this changed pressure differen-tiaI now causes the valve 24 to attain the full open position as is illustrated in Figure 2. Thereafter, the vehicle v passes ~55~7~2 1 the region 44 and in so doiny passes beneath the valve 24 ultimately to reach the position of a detector 36 which now causes the actuator to revert the valves 56 a~ld 58 to their original positions as is shown in Figure 3.
Figure 4 illustrates in diagrammatic form the fashion in which the two butterfly valves 56 and 58 are actuated between the position shown in Figures 1, 2 and 3 7 As illustrated in Figure 4, a common actuator of any conventional form and as is indicated by the reference character 60 is controlled by the detectors 30 and 36 and the two valves 56 and 53 are provided with crank arms 62 and 64 which are pivotally interconnected by a link 66 and are also connected to the actuator rod 68 of the device 60. The device 60 is adapted to move its rod 68 back and forth in the fashion indicated by the double headed arrow in Figure 4 correspondingly to pivot the valves 56 and 58 about their axes 70 and 72 between the positions indicated in Figures 1 and 2. The actuator may be o~ any suitable form and as illustrated is double acting, same being energized to act in one direction in response to a signal from the detector or sensor 3~ and in the opposite direction in response to a signal from the detector or sensor 36. The detectors 30 and 36 can be of any conventional type as, for example, they may be photodetector devices as illustrated in Figure 4 operative to be actuated to produce an output signal when the vehicle v passec the light beams from the lamps L normally incident thereon. Each lamp/detector pair is staggered as shown so that any gap between successive vehicles of a vehicle train will not allow the light beam to pass.
In the~embodiment of Figures 5-7, the apparatus is the same as is de~cribed in conjunction with Figures 1-3 but, in this instance/ an auxiliary pump 74 is provided having an inlet 76 connected between the two valves 22 and 24 in place ~1~557~Z

1 of vent 18. The outlet 78 of this pump 74 is provided with a valve 80 which is mov~ble between the full open position shown in Figure 5 to the fully closed position shown in Figure 6. When the valve 80 is in the ful:Ly open position as shown in Figure 5, the auxiliary pump 74 withdraws air from the section between the valves 22 and 24 which, although it is less than the flow through the branch 42, nevertheless is of sufficient flow rate as to create a pressure differential across the valve 22 which maintains it in the upwardly swung, open position and acts to draw vehicle v through the line 10 as is shown in Figure 5. An approaching vehicle, then, can freely pass beneath the valve 22. As soon as the vehicle passes the position of the sensor 30, the actuator means for the valves 56 and 58 which is also connected to the valve 80 moves these several valves to the position shown in Figure 6I thus discharging air through the branch 48 and moving the vehicle along with it and, at the same time, upsetting the pressure differential previously across the valve 24 and now moving it to the upwardly swung or open position as is illustrated in Figure 6 whi~e closing valve 22.
As soon as the vehicle passes the second sensor 36, the actuator means reverse the valves to their original positions, as is illustrated in Figure 7.
In the embodiment shown in Figure ~, the arrangement is generally similar to that illustrated in Figures 5-7. However, in this case, the auxiliary pump 74' has its inlet 76' connected between the two valves 22 and 24 but in this case its outlet .
, .~ . , 82 discharges downstream from the branch 42, the capacity of the pump means 74' being but a fraction o the flow of the main pump. Thus, when the valves 56 and 58 are reversed in their positions and flow is dow~wardly through the leg 48 of the main pump 38, the auxiliary pump 74' cannot sustain ~he ~9_ .

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1 pressure differential which maintained the valve 24 closed and, instead, the pressure differential across this valve 24 alters or changes so that it moves to the upwardly swung position while, at the same tim~, the valve 22 swings downwardly to the closed position behind the entering vehicle. The detectors 30 and 36 operate in the same fashion as previously described.
With the systems according to the present invention, the main pump 14 in each case can be operated at pre~sure differ-entials correspondingly to produce high mass rates of flow whereby the vehicles which are heavily laden can be adequately moved through the pipeline system. At the same time, the momentum of the vehicle is minimally disturbed by the blocking valves 22 and 24 associated with the pumping stations and, instead, a change of flow in the system is effective to produce the phenomenon which alters the pressure differentials across the blocking valves ~2 and 24 to move them back and forth between their closed and opened positions.
It will be appreciated that the basic principle of this invention involv~s air flow control in the vicinity of the two openly urged flapper valves 22 and 24 which adjusts the pressure differential alternately across the valves either to close them or to allow them to swing to open position.

Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a transport system including a continuous conduit for convey-ing wheeled vehicles therein, and pump means for discharging pressurized air through one of a first and a second pump outlet branch into said conduit, the combination of:
a first overhead-suspension swingable valve adapted to move between a closed position blocking off said conduit and an open position permitting a vehicle to sweep past, a second overhead-suspended swingable valve downstream of the first valve adapted to move between a closed position blocking off said conduit and an open position permitting a vehicle to sweep past, said first and second valves being spaced from each other along said conduit, vent means connected to the conduit between said first and second valves, opening means urging said first and second valves to the open position, air flow control means associated with said pump means and positioned one in each of said first and second branches for alternately directing air through the first branch and into said conduit and against the back of the first valve to close said first valve behind a vehicle while allowing said second valve to open under the action of its opening means ahead of said vehicle, and directing air through said second branch and into said conduit and against the back of the second valve to close said second valve behind said vehicle while allowing said first valve to open under the action of its open-ing means, and means responsive to the position of said vehicle for actuating said air flow control means in said first and second branches.

2. The system of claim 1 wherein said vent means includes auxiliary pump means having an inlet connected to the conduit between said first and second valves.

3. The system of claim 2 wherein said auxiliary pump means includes an outlet connected to said conduit down-stream of the second valve.

4. The system of claim 1 wherein the conduit upstream of the first valve is inclined downwardly towards the first valve.

5. The system of claim 2 wherein said auxiliary pump means includes a valve controlled by the means actuating said air flow control means.

6. The system of claim 1 wherein said opening means comprises a weight acting to urge each said valve toward open position.

7. The system of claim 1 wherein said opening means comprises a spring acting to urge each said valve toward open position.

8. The system of claim 1 wherein each valve when moved to the closed position seals against the inside wall of the conduit.

9. The system of claim 1 wherein the air flow con-trol means is connected to the top of the conduit to direct air to the conduit and against the backs of said valves and said valves are pivotally suspended adjacent the upstream side of said connection of the air flow control means and the conduit.