US3795263A

US3795263A - Pneumatic system controlling operation of a filling valve in a container filling machine

Info

Publication number: US3795263A
Authority: US
Inventors: C Wilhere
Original assignee: HORIX Manufacturing Co
Current assignee: HORIX Manufacturing Co
Priority date: 1972-11-27
Filing date: 1972-11-27
Publication date: 1974-03-05
Anticipated expiration: 1991-03-05
Also published as: CA993363A; JPS5234992B2; JPS49135779A; GB1409189A

Abstract

First and second fluidic control devices of special construction receive streams of air that are deflected to atmosphere at predetermined intervals by means of jets of air controlled by valves and the liquid level in a container as the machine moves through its cycle. At one point in the cycle, air pressure from one of the fluidic control devices causes the filling valve to open and remain open until a jet of control air is delivered to the fluidic control device when the desired liquid level in the container is reached, whereupon the control device is vented to atmosphere and the filling valve closes. If a container is not present when it should be, the filling valve will not open and there will be no blow-down through the level sensing tube.

Description

1 1 Mar. 5, 1974 1 PNEUMATIC SYSTEM CONTROLLING OPERATION OF A FILLING VALVE IN A CONTAINER FILLING MACHINE [75] Inventor: Charles V. Wilhere, Pittsburgh, Pa.

[73] Assignee: Horix Manufacturing Company, Pittsburgh, Pa.

[22] Filed: Nov. 27, 1972 [21 Appl. No.: 309,733

[56] References Cited UNITED STATES PATENTS 3,441,066 4/1969 Wilhere 141/148 3,545,502 12/1970 Nunl-ist 141/141 X Primary ExaminerHouston S. Bell, Jr. Assistant ExaminerFrederick R. Schmidt Attorney, Agent, or Firm-Brown, Murray, Flick &

Peckham I57 I ABSTRACT First and second fluidic control devices of special construction receive streams of air that are deflected to atmosphere at predetermined intervals by means of jets of air controlled by valves and the liquid level in a container as the machine moves through its cycle. At one point in the cycle, airpressure from one of the fluidic control devices causes the filling valve to open and remain open until a jet 'of control air is delivered to the fluidic control device when the desired liquid level in the container is reached, whereupon the control device is vented to atmosphere and the filling valve closes. If a container is not present when it should be, the filling valve will not open and there will be no blow-down through the level sensing tube.

10 Claims 8 Drawing Figures 1 PNEUMATIC SYSTEM CONTROLLING OPERATION OF A FILLING VALVE IN A CONTAINER FILLING MACHINE In rotating machines for filling containers with liquid product to a predetermined level, different systems have been devised for opening and closing the filling valves at the right times. These control systems often are pneumatic systems. They may make use of valves only, or valves and fluid amplifiers for controlling the flow of the air in the systems. Although they accomplish their purpose, it is desirable to provide a simpler system with a minimum of valves and other parts and that will be less expensive than the known control systerns. These are the purposes and objects of the present invention, in which the switching of the direction of fiow of air through the control system is accomplished mainly by jets of air impinging on main air streams to deflect them from their normal paths.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. Iiis a fragmentary vertical section of a single filling station of a container filling machine,;with some parts shown in elevation; I i l FIG. 2 is a partial end view;

F IG. 3 is a diagram of the pneumatic pressure system I that controls the filling valve, showing the system be fore a container is in filling position;

FIG. 4 is a diagram of the system when'a container is in filling position, but filling has notyet'start'ed;

FIG. 5 is a diagramof the system during-filling,

filling is stopped; and

FIGS. 7 and 8 are diagramscorresponding to FIGS.

3 and 5, respectively, of a modification.

Referring to FIGS. 1 and 2 of the drawings, the type of container filling machinewith which this invention is most useful is the kind in which severalfillingstations are spaced circumferentially around a rotating center post l supporting a liquid product tank2. At each station a container 3, such as a bottle, is raised byv a traveling supporting member 4 in a well-known, manner to cause the open upper end of the bottleto firstv engage a guide 6 at the lowerend of-the filling tube 7 and then to move the guide upwardly as the bottle moves up around the tube. The guide is supported in a ring 8 suspended from the lower ends ofa pair of vertical guide rods 9 shown in FIG.;2 that are slidably mounted in bushings 10 secured to the opposite sides ofa horizon- I tal arm 11 projecting radially outwardly from the bottom of thetank. :As-the post rotates, itcarries the-arm and like arms at the other stations ofthe machine in a circle around the axis of the post. The upper ends of the two guide rods are mountedin a cross bar 12 normally resting on top of the arm and provided centrally with an upwardly projecting boss I v The tank'is provided above the inner end of the arm with an outlet port I5 that opens into the top ofa longitudinal passage 16 in the arm. The inner end of the arm is closed by a plug 17. The bottom ofthe arm hasan outlet port 18 connected by a coupling 19 to the upper end of the filling tube. Inside the arm, between its, inlet and outlet ports, there is a valve seat 2I that normally. is closed by a filling valve member 22 mounted on the inner end of a horizontal piston rod 23 slidable in a bushing 24 rigidly. mounted in the arm between its outer end and its outlet port. Mounted on the outer end of this piston rod is a piston 25, between which and a 3Ov FIG. 6 is a diagram of the system-at the moment that v cup 26 projecting from the outer end of the arm a coil spring 27 is compressed to hold the valve member against seat 21. Between'the piston and bushing 24, the arm is provided with an inlet 28 for air under pressure, by which the piston can be moved toward the outer end of the arm to unseat the valve member so that liquid from the tank canflow past it and down through the filling tube into the bottle. 7

After a bottle has been placed on its support 4 and elevated around the lower end of the filling tube, thereby raising guide 6 and cross bar 12, the rotation ment so that air under pressure will be delivered to the arm through its inlet 28 to open the filling valve. The

pneumatic pressure system that accomplishes this is carried by the machine, except for the primary source of air pressure, such as an air compressor or pressure tank, and there is a separate pneumatic pressure system for each individual filling valve. Most of the elements of the pneumatic system are enclosed in a case 30 supported by a bar 31 extending outwardly from the upper end of a post 32 screwed into the marginal area of the bottom of the tank that projects beyond itsside wall. Reference will now be made to FIGS. 3 to 6 toexplain the construction and operation of the pneumatic system. Y

Referring to. FIG. 30f the drawings, inside of case 30 of FIG. 1 there is an air-conducting element 35 having an inlet connected'by a main supply tube 36' to'the source of air pressure 37.'This element'also has 'a main outlet for the air, and a bypass 38 that can exhaust to atmospherewhen a closure member39 is-separated from the by-pass outlet. This separation is effected by the elevation of a container into filling position. Referring back to FIG. I, the by-pass extends'out ofthe case and up through the topofa block 41 attached to the side of the case. Normally resting on top of the by-pass and closing it is the closure member 39, which K is mounted on the upper end of a rod 142 that is slidable vertically in the block., The rod also extends down below the block and carries a weight 43 on its lower 13 on .top

vice 45 isprovided with a control chamber 46 and an output chamber 47 that are connected by a central orifice 48. The outer endsof the two chambers are provided with air inletsaligned with the central orifice.

Nozzles

49 and 50 extend from these inlets toward that orifice, but their inner ends are spaced from it. The two inlets are connected by

tubes

51 and 52, respectively, to a tube 53 leading from supply tube 36. The modulator is so constructed thatif thestreams of air issuing from the two nozzles are not interfered with, they will impinge upon each other in the area between the-central orifice 48 and the outlet of nozzle 49 in the output chamber and raise the air pressure therein. The outlet of air conducting element 35 is connected by a tube 54 with the side of the control chamber46 in a position to cause a jet of air to impingeupon the side of the stream issuing from the nozzle in that chamber. This deflects the stream laterally so that the stream from nozzle 49 can enter the control chamber, which is vented tothe atmosphere by way of an outlet 55. The output chamber, on the other hand, is provided with an outlet connected by a tube 56 with a pneumatic relay 66 which, when opened by air from the tube, connects pressure source 37 or some other source of high pressure with a tube 66A leading to the air inlet 28 (FIG. 1) of the filling valve.

The outlet of output chamber 47 also is connected by another tube 57 with the side of the control chamber 58 of the second fluidic control device 59. The inlets to the two nozzles of this device are connected by

tubes

60, 61 and 62 with the main air supply tube 36. The control chamber has an outlet 63 to atmosphere, and

the output chamber 64 has an outlet connected by a tube 65 to the side of the control chamber of the first impact modulator.

Since in FIG. 3 the opposed streams of air in the second modulator 59 are not being deflected by deflecting jets of air, they are impinging on each other in the output chamber, which causes the air therein to build up pressure and flow out through tube 65 to the control chamber of the other modulatonThe jet of air issuing from this tube is directed to deflect the streams from the two

nozzles

49 and 50, even if the flow from tube 54 is shut off. The side of the control chamber of the second modulator 59 is also connected by a tube 67 to the outlet of a normally closed start-fill valve 68, the inlet of which is connected to the main supply tube 36. This valve is provided with an actuating member 69 that extends out of case 30 and that engages a stationary cam (not shown) for a moment during each revolution of the filling machine, whereby to open the valve for a moment to deliver a jetof deflecting air to the side of control chamber 58. j

The output, chamber of thefirst modulator likewise is connected through its outlet tube 56 and a tube 71 with a junction chamber 72, from the bottom of which a tube 73 extends down through arm 11 and a slot 74 in piston rod 23 and into the upper end of a levelsensing tube 75 encircling the filling tube.,The sensing tube extends down into a container while it is being filled, with the lower end of the tube located at the liquid level desired-in the container, as is well known. Another tube.76 extends from junction chamber'72 back to the side of the control chamber 46 in the firstzmodulator for delivering a jet of deflecting air there on occasion. i

There also is a second normally closed valve,'i.e., a blow-down valve 80, in case 30. It is provided with an actuating member 81 projecting from the case and which likewise engages a stationary cam for a moment during each revolution of the machine to open the valve for a short period. The inlet of this valve is connected by a tube 82 with the main supply tube 36, and the valve outlet is connected to the inlet of an airconducting element 83 like element 35. The main outlet ofthis element is connected by a tube 84 tojunction chamber 72. The air-conducting element also is provided with a by-pass 86 .to atmosphere that normally is open but that is closed by a closure member 87 when a container is raised into filling position. As shown in FIG. 1, this closure member likewise is mounted on the vertical rod 42, but it is below block 41 and engages the outlet of the by-pass 86 that extends from airconducting element 83 into the block and downwardly out of its bottom. The closure member is slidable on the rod, where it is supported by a coil spring 88 so that the rod can be raised different distances by containers of different'heights without interference from the closure member in its upper position.

As indicated before, when there is no container in position at a filling station served by the pneumatic control system illustrated in FIG. 3, the flow of air is as indicated by the arrows in that diagram, so the filling valve is closed. When a bottle is placed on its support and is raised, it raises rod 42 to open by-pass 38 and to close hy-pass 86 as shown in FIG. 4. Although this cuts off flow of deflecting air through air-conducting'ele- 'ment 35 to the side of control chamber 46 of the first modulator 45, the pattern of air flow in that device remains the same as before because the air streams from

nozzles

49 and 50 are still deflected by the jet of air entering through tube 65 from the output chamber of the other modulator. However, the rotating machine soon carries the actuating member 81 of v the blow-down valve into engagement with its cam so that the 'valve is opened momentarily to allow a jet of air to flow into junction chamber 72 and down. through the level-sensing tube to clear that tube of any liquid product that'may be in it and to remove drops of liquid left on its lower end, as about to be filled. This jet of air is prevented by a check valve 89in tube 71 from flowing through that tube. If no container is present, closure member 87 will not have been raised to close by-pass 86, so there will be no blow-down of drops of liquid' onto the machine or onto adjacent containers. This helps to keep the machine and its surroundings clean.

Immediately after the blow-down,. the actuating member 69 of the start valve strikes its cam to open that valve to cause a jet of deflecting air to strike the side of the impinging streams in the second modulator 69, as shown in FIG. 5. This deflects them through the chamber outlet to the atmosphere, whereby the flow of air through tube 65 from output chamber 64 is cut off. It follows that since there no longer are any jets of deflecting air entering the side of control chamber 46 of the first modulator, the streams from the nozzles therein now impinge in the output chamber and build up pressure in tube 56 so that pneumatic relay 66 is opened to deliver air to piston 25 in arm 11, thereby moving the piston to open the filling valve. Air from the output chamber likewise flows through

tubes

56 and 57 to the control chamber of the second modulator to maintain the deflection of the air streams therein after the start valve closes on leaving its c'am. Furthermore, air from output chamber 47 also flows through tube 71 to the sensing tube in a continuous stream.

With the filling valve open, the bottle is filled with liquid from the tank until the liquid rising in the bottle shuts the outlet of the sensing tube. Immediately upon this occurring, air pressure'is built up in tube 76 between the junction chamber 72 and the control chamber 46 of the first modulator so that the impinging streams therein are again deflected to the exhaust port of the control chamber, as shown in FIG. 6. This shuts off flow of air through tube 56 to allow pneumatic relay 66 to close, whereupon the spring 27 will close the filling valve. Stopping of air flow through tube 56 also stops the flow ofdeflecting air through tube 57 to the second modulator, so the opposed air streams in that device again impinge in its output chamber 64, from which air flows out through tube 65 and back to the control chamber of the first modulator to maintain air stream deflection therein even though the deflecting air from junction chamber 72 was shut off the moment the jet of air from tube 76 entered control chamber 46. A variable restrictor 91 in tube 53 permits the system to be tuned so that there will be the correct air flow to the nozzles of both modulators.

As soon as the filled bottle is lowered to release it from guide 6, the closure member 39 for the first airconducting element 35 is allowed to descend and close its by-pass 38, and the closure 87 for the second aireonducting element 83 drops away from its by-pass 86. Consequently, the circuit returns to the condition shown in FIG. 3, ready for the next container to be filled.

The pneumatic pressure system disclosed herein operates with only two fluidic control devices and two cam-operated valves. The container itself determines whether the filling valve will open and the blow-down operate. In the absence of a container the filling valve remains closed and the blow-down does not operate even though the machine otherwise goesthrough its eycle.

In the modification illustrated in'FIGS. 7 and 8 most of the system is the same as the one just described, so like elements have been given the same reference numbers for ease of comparison. The'differences lie in the elimination of variable restrictor 9], tube 71 and check valve 89, and the substitution therefor ofa third fluidie control device or impact modulator 92. The inlets of control chamber 93 and output chamber 94 of this modulator are connected by

tubes

95 and 96 to a tube 97 leading from supply tube 36. The outlet of output chamber 64 of modulator-59 is connected by a tube 98 to the side of control chamber 93, while the outlet of output chamber 94 of the third modulator is connected to junction chamber 72 by means ofa tube 99. As will be seen by the arrows in FIG. 7, when no container is present there will be no air flow from the third modulator to the junction chamber and liquid level sensing tube 73.

When a container is raised into filling position and the start switch 68 is opened, theflow from output chamber 64 of modulator 59 stops as it did in FIG. 5, so the flow through tube 98 to the third modulator likewise stops, as indicated in FIG. 8. This allows the two streams of air from the nozzles in modulator 92 to meet in its output chamber 94 and flow out through tube 99 to junction chamber 72 and the level-sensing tube. When the container is filled, the system reverts to what is shown in FIG. 6. Any flow of air up through tube 99 during blow-down cannot affect the operation of the system. Since the first impact modulator 45 does not have to supply air for liquidlevel-sensing, it no longer isnecessary to have a variable restrictor in tube 53 for adjusting the flow thercthrough-as compared with the flow through

tubes

62 and 97.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

l. In a container filling machine, a'pneumatic pressure system for controlling the operation of means for opening a filling valve, the system comprising first and second fluidic control devices each provided with a controlchamber and an output chamber connected by an orifice, each control chamber having an outlet to atmosphere and each output chamber having an air pressure outlet, each fluidic control device having a pair of opposed inlets aligned with said orifice wherein in each of the fluidic control devices one of said pair of inlets opens into said control chamber and the other of said pair of inlets opens into said outlet chamber, means for continuously delivering air under pressure to both inlets simultaneously to form air streams that normally meet in the output chamber to produce air pressure therein, a first conduit connecting the pressure outlet of the first control device with said valve-opening means to open the filling valve when there is air pressure in said conduit, a second conduit connecting the pressure outlet of the first control device with the control chamber of the second control device to direct a jet of air against the side of the air stream therein to defleet the streams in that device to the outlet of the control chamber, a third conduit connecting the pressureoutlet of the second control device with the control chamber of the first control device to direct a jet of dc fleeting air against the side of the air stream therein, a first means for conducting air from said air-delivering means to the control chamber of the first control de-' vice todirect a jet of deflecting air against the side of the air stream therein while no container is in filling position, means operated by a container in filling position for stopping the jet of deflecting air from said conduct ing means, a normally closed valveconnecting said air delivering means with the control chamber of the second control device and adapted to be opened while a container is in filling position to direct a pulse of de fleeting air against the side of the air stream in the con trol chamberof the second control device, whereby air pressure will be produced'in the output chamber of the first control device to operate said filling valve opening means and deliver air to said second conduit, and second means for deflecting the air stream in the control chamber of the first control device as soon as a container is filled. I

2. In acontainer filling machine system according to claim 1, said second means for deflecting the air stream in the control chamber of the first control of the first eontroldevice including a level-sensing tube having an inlet and an outlet, the'outlet of the-tube being insert? able in the upper part of a container being filled, a fourth conduit connecting the pressure outlet of the first control device with the inlet ofsaid tube for delivering a stream of air from the tube outlet during container filling, and a fifth conduit connecting" thetube inlet with the control chamber of the first control device to direct a pulse of deflecting air against the side of the air stream therein when rising liquid in a container closes the outlet of said tube. I

3. In a container filling machine system according to claim 2, a normally closed blow-down valve connecting said air-delivering means with said tube inlet and adapted to be opened and closed before said filling valve is opened, and a eheck valve in said fourth eonduit for preventing air flow back through that conduit while the blow-down valve is open.

4. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for diverting air from that valve to atmosphere if said blowdown valve is opened when no container is in filling position. 1

5. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for conducting air between them, said lastmentioned air-conducting means including a by-pass to atmosphere, a closure member spaced from the bypass, and means actuated by a container in filling position for moving said closure member into by-pass closing position.

6. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for conducting air between them, said lastmentioned air-conducting means including a by-pass to atmosphere, and a closure member spaced from the bypass, said first air conducting means including a by-pass to atmosphere, and a closure member normally closing the last-mentioned by-pass, and said'system including a vertically movable container guide, and means movable upwardly by said guide to lift said first-mentioned closure member into by-pass closing position and to simultaneously lift said second-mentioned closure member-away'from the adjoining by-pass to open it.

7. in a container filling machine system according to claim 1, said first air-conducting means including a normally closed by-pass to atmosphere, and means actuated by a container in filling position-for opening said by-pass. i

8. ln a container filling machine system according to claim 1, said first air-conducting means including a bypass to atmosphere, a closure membernormally closing said by-pass, and means actuated by a container. in filling position for moving said closure member away from said by-pass to open it.

9. In a container filling machine system according to claim 8, said means actuated by a container in filling position including a vertically movable container guide, means for raising a container beneath said guide to raise the guide, and means movable upwardly by said guide for lifting said closure member.

10. In a container filling machine system according to claim 1, said second means for deflecting the air stream in the control chamber of the first control of the first control device including a level-sensing tube having an inlet and an outlet, the outlet of the tube being insertable in the upper part of a container being filled, a third fluidic control device provided with a control chamber having an outlet to atmosphere and with an output chamber having an air pressure outlet, the chambers of said third device being connected by an orifice and each chamber having an opposed inlet aligned with that orifice, meansfor continuously delivering air under pressure to both of said last-mentioned inlets simultaneously, a conduit connecting the pres-- sure outlet of the second control device with the control chamber of the third control device to direct a jet of deflecting air into it, a conduit connecting the pressure outlet of the third control device with the inlet of said tube, and a conduit connecting the tube inlet with the control chamber of the first control device to direct the outlet of said tube,

Claims

1. In a container filling machine, a pneumatic pressure system for controlling the operation of means for opening a filling valve, the system comprising first and second fluidic control devices each provided with a control chamber and an output chamber connected by an orifice, each control chamber having an outlet to atmosphere and each output chamber having an air pressure outlet, each fluidic control device having a pair of opposed inlets aligned with said orifice wherein in each of the fluidic control devices one of said pair of inlets opens into said control chamber and the other of said pair of inlets opens into said outlet chamber, means for continuously delivering air under pressure to both inlets simultaneously to form air streams that normally meet in the output chamber to produce air pressure therein, a first conduit connecting the pressure outlet of the first control device with said valve-opening means to open the filling valve when there is air pressure in said conduit, a second conduit connecting the pressure outlet of the first control device with the control chamber of the second control device to direct a jet of air against the side of the air stream therein to deflect the streams in that device to the outlet of the control chamber, a third conduit connecting the pressure outlet of the second control device with the control chamber of the first control device to direct a jet of deflectIng air against the side of the air stream therein, a first means for conducting air from said air-delivering means to the control chamber of the first control device to direct a jet of deflecting air against the side of the air stream therein while no container is in filling position, means operated by a container in filling position for stopping the jet of deflecting air from said conducting means, a normally closed valve connecting said air delivering means with the control chamber of the second control device and adapted to be opened while a container is in filling position to direct a pulse of deflecting air against the side of the air stream in the control chamber of the second control device, whereby air pressure will be produced in the output chamber of the first control device to operate said filling valve opening means and deliver air to said second conduit, and second means for deflecting the air stream in the control chamber of the first control device as soon as a container is filled.

2. In a container filling machine system according to claim 1, said second means for deflecting the air stream in the control chamber of the first control of the first control device including a level-sensing tube having an inlet and an outlet, the outlet of the tube being insertable in the upper part of a container being filled, a fourth conduit connecting the pressure outlet of the first control device with the inlet of said tube for delivering a stream of air from the tube outlet during container filling, and a fifth conduit connecting the tube inlet with the control chamber of the first control device to direct a pulse of deflecting air against the side of the air stream therein when rising liquid in a container closes the outlet of said tube.

3. In a container filling machine system according to claim 2, a normally closed blow-down valve connecting said air-delivering means with said tube inlet and adapted to be opened and closed before said filling valve is opened, and a check valve in said fourth conduit for preventing air flow back through that conduit while the blow-down valve is open.

4. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for diverting air from that valve to atmosphere if said blowdown valve is opened when no container is in filling position.

5. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for conducting air between them, said last-mentioned air-conducting means including a by-pass to atmosphere, a closure member spaced from the by-pass, and means actuated by a container in filling position for moving said closure member into by-pass closing position.

6. In a container filling machine system according to claim 3, means between the blow-down valve and said tube inlet for conducting air between them, said last-mentioned air-conducting means including a by-pass to atmosphere, and a closure member spaced from the by-pass, said first air conducting means including a by-pass to atmosphere, and a closure member normally closing the last-mentioned by-pass, and said system including a vertically movable container guide, and means movable upwardly by said guide to lift said first-mentioned closure member into by-pass closing position and to simultaneously lift said second-mentioned closure member away from the adjoining by-pass to open it.

7. In a container filling machine system according to claim 1, said first air-conducting means including a normally closed by-pass to atmosphere, and means actuated by a container in filling position for opening said by-pass.

8. In a container filling machine system according to claim 1, said first air-conducting means including a by-pass to atmosphere, a closure member normally closing said by-pass, and means actuated by a container in filling position for moving said closure member away from said by-pass to open it.

10. In a container filling machine system according to claim 1, said second means for deflecting the air stream in the control chamber of the first control of the first control device including a level-sensing tube having an inlet and an outlet, the outlet of the tube being insertable in the upper part of a container being filled, a third fluidic control device provided with a control chamber having an outlet to atmosphere and with an output chamber having an air pressure outlet, the chambers of said third device being connected by an orifice and each chamber having an opposed inlet aligned with that orifice, means for continuously delivering air under pressure to both of said last-mentioned inlets simultaneously, a conduit connecting the pressure outlet of the second control device with the control chamber of the third control device to direct a jet of deflecting air into it, a conduit connecting the pressure outlet of the third control device with the inlet of said tube, and a conduit connecting the tube inlet with the control chamber of the first control device to direct a pulse of deflecting air against the side of the air stream therein when rising liquid in a container closes the outlet of said tube.