Liquid-flow control apparatus

Abstract

 A dosing device for filling liquid into containers comprises a filler body 1 and a metering device 2. The device 2 communicates with the interior of a rotary valve 7 through an end cover 9 of the valve housing 10, the valve 7 including a valve seat 11 and a check valve closure member 12 spring- biased towards the seat 11. The valve 7 includes three rotary ports 34, 34' and 39 and two fixed ports 36 and 40. Downstream of the port 40 is an anti-drip suction-producing device 8 of a piston-and-cylinder form whereof the stroke of the piston 15 is adjustable. Upstream of the port 36 is a throttling valve 24 lowerable into an operative position downstream of inlet holes 21 from a liquid-containing tank. For a high viscosity liquid, it is drawn into the device 2 through the holes 21, the ports 36 and 34 and the end cover 9, the valve 7 is rotated to align the port 34' with the port 40 and to close the port 36, and the liquid is then expelled from the device 2 through the end cover 9, the ports 34' and 40 and an outlet nozzle 38. A low viscosity liquid is drawn into the device 2 through the holes 21, the lowered valve 24, the ports 36 and 34 and the end cover 9, and is then expelled from the device 2 through the end cover 9, the valve 11,12, the ports 39 and 40 and the nozzle 38.

Description

[0001] The present invention relates to apparatus for controlling liquid flow.

[0002] According to one aspect of the present invention, there is provided apparatus for controlling liquid flow, comprising duct means, a rotary valve interposed in said duct means and including a fixed inlet port and a fixed outlet port arranged at an angular interval from each other, and first and second rotatable ports arranged at said interval from each other, characterized in that a check valve is carried by said rotary valve and arranged to close said second rotatable port.

[0003] Owing to the invention, it is possible to provide apparatus which smoothly and efficiently controls the flow of high viscosity liquids as well as low viscosity liquids.

[0004] According to another aspect of the present invention, there is provided dosing apparatus for emitting liquid doses, comprising an outlet chamber, means for supplying doses of liquid to said chamber and including an inlet valve to said chamber, outlet means from said chamber, and a suction-producing device communicating with said chamber at a location downstream of said inlet valve and upstream of said outlet means and arranged to produce suction in said chamber, said device including a wall portion of said chamber movable inwardly and outwardly to reduce and increase, respectively, the internal volume of said chamber, and adjusting means for adjusting the stroke of said wall portion.

[0005] In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-

Fig. 1 shows a view, mainly in vertical section, of a dosing apparatus for filling liquid into containers,

Fig. 2 shows a view which is mainly a horizontal section taken on the line A-A of Fig. l,

Figs. 3 and 4 are respective views similar to Fig. 1, but diagrammatic and illustrating the apparatus during high viscosity liquid prefilling and filling stages, respectively,

Figs. 5 and 6 are respective views similar to Figs. 3 and 4, but during low viscosity liquid prefilling and filling stages, respectively, and

Fig. 7 shows two half-views of a modification of the apparatus, an upper half-view being substantially a vertical section, and the lower half-view being a sectional side elevation.

[0006] Referring to the drawings, the apparatus comprises a filler body 1 and a metering device 2, the filler body 1 having an upper portion 3 extending through and projecting upwards beyond the bottom wall 4 of a liquid tank 5 and communicating with the tank 5, and an intermediate portion 6 fixed to the upper portion 3 by a threaded nut 20, and a suction-producing device 8. The metering device 2 communicates via a tube 35 with a rotary valve 7 through an end cover 9 of the rotary valve housing 10, the rotary valve 7 including an internal built-in valve seat 11 and a check valve closure member 12 urged towards the valve seat 11 by a helical tension spring 12', a bushing on the valve stem 12 " limiting the downward stroke of the member 12. The rotary valve is rotatable through 113° by an air cylinder 41 or a mechanical drive, itself controlled by a timer, and includes three rotary ports 34, 34' and 39 arranged at intervals of 67° between the ports 34 and 34' and of 113° between the ports 34' and 39, and two fixed ports 36 and 40 at 180° intervals. The device 8 is fixed to a lower cylindrical part of the intermediate portion 6 and includes a vacuum chamber 8' separated from the interior of the filler body 1 by a roll membrane 14 and connected to a vacuum pump (not shown), a membrane piston 15 being pressed towards a stop pin 16 by a spring 17 when the chamber 8' is not under vacuum, and the length of stroke being adjustable by a screw 18 centrally threaded in a vacuum chamber cover 19 of the device 8. The negative pressure in the chamber 8¹ can be adjusted with a bleeder nozzle (not shown).

[0007] The upper portion 3 has inlet openings 21 for high viscosity liquid. Below the openings is an O-ring 37 mounted in an annular groove in the inner surface 22 of the portion 3.

[0008] An inlet piston 23 has, for low viscosity liquid, an inlet check valve 24 built-in. When the filler is used for low viscosity liquid the piston 23 is lowered axially in the portion 3 to seal against the O-ring 37. The piston 23 is operated by an air cylinder not shown in Fig. 1.

[0009] The piston 23 has to be lifted by the air cylinder to release trapped air from the body 1. Vertical grooves 25 are made in the surface 22 to allow the escape of surplus liquid when the piston is lowered.

[0010] The lower portion of the filler body 1 comprises a tubular part 26 which is attached to the intermediate portion 6 by means of a fastening nut 27 screwed on a threaded end 28 of the portion 6. A flexible nozzle 38 is mounted in a groove 29 on the lower end zone of the tubular part 26. The nozzle is made of a resilient material and has outlet lips which are pressed sealingly together by the resilience of the material.

[0011] The metering device comprises a metering cylinder 30 comprised of a cylindrical body 31, a piston 32 and a piston rod 33.

Operating the filler for high viscosity liquid filling

[0012] With the piston 23 permanently in its upper position, the downward stroke of the piston 32 in the metering cylinder 30 permits liquid to flow into the cylinder from the tank 5 through the openings 21, 36 and 34 and the end cover 9 and the tube 35 (Figure 3). When the downward stroke is completed, the rotary valve 7 is turned through 113° by means of the air cylinder 41 or mechanical device to close the port 36 and open the ports 34' and 40 to the nozzle 38. When the metering piston 32 moves upward the liquid flows from the metering cylinder 30 to the nozzle 38 and into a container to be filled (Figure 4).

[0013] As the metering piston 32 reaches its top position the rotary valve 7 turns back 113°. When the port 40 is closed, the vacuum chamber 8' is immediately evacuated and a negative pressure is created in the part 26.

Operating the filler for low viscosity liquid filling

[0014] With the port 34 open, the metering cylinder 30 is filled by a downward stroke of the piston 32. The piston 23 is in its top position to release air. When the filling starts, the piston 23 is moved downwards to seal against the O-ring 37. Surplus liquid in the filler body 1 will then partly escape to the tank 5 through the grooves 25 and partly be pressed out through the check valve 12 (Figure 5). When the piston 32 is moved upwards the check valve 24 closes and the check valve 12 opens and liquid is discharged through the nozzle 38 (Figure 6).

[0015] When the piston 32 ends its upward stroke the spring-loaded check valve 12 closes. 41

[0016] If the check valve 12 does not create the necessary negative pressure in the nozzle 38, the device 8 is operated by an external vacuum control valve (not shown).

[0017] The dosing apparatus described above has an advantage that it can be changed between handling low viscosity liquid and handling high viscosity liquid by simply raising or lowering the piston 23 and by simply rendering operative or'inoperative the rotary valve 7, so that it is not necessary to dismantle and change any part of the apparatus. Another advantage is that the vacuum in the chamber 8' can be readily adjusted without interrupting production.

[0018] In the modification shown in Figure 7, the membrane piston 15 of the device 8 has been replaced by a piston 115 sealingly encircled by an O-ring 110 housed in an annular internal groove in a cylinder 103. The piston 115 includes a central rod 119 on which is held by a nut 116 a piston ring 113 between two clamping rins 104 and 105. The piston 115 is double-acting, compressed air being introduced alternately through parts 106 and 107 at respective opposite sides of the piston ring 113. A set screw 118 screwed axially into the outer end of the cylinder 103 adjustably sets the stroke of the piston and thus the magnitude of the suction produced in the chamber between the valve 7 and the nozzle 38. A boss or a hole 114 for an Allen key or the like is formed in that end of the piston 115 bounding the latter chamber, to permit tightening of the nut 116 without the need to dismantle the device 8.

Claims

1. Apparatus for controlling liquid flow, comprising duct means (1), a rotary valve (7) interposed in said duct means (1) and including a fixed inlet port (36) and a fixed outlet port (40) arranged at an angular interval from each other, and first and second rotatable ports (34,39) arranged at said interval from each other, characterized in that a check valve (11,12) is carried by said rotary valve (7) and arranged to close said second rotatable port (39).

2. Apparatus according to claim 1, and further comprising a metering device (2) communicating with the rotary valve (7) by way of a further port (9) via which said metering device (2) can receive a desired amount of liquid through said fixed inlet port (36) and said first rotatable port (34) and can emit said amount through said second rotatable port (39) and said fixed outlet port (40).

3. Apparatus according to claim 2, wherein said rotary valve (7) comprises a third rotatable port (34¹) which can be brought, by rotation of said rotary valve (7), to a position substantially aligned with said fixed outlet part (40) and through which and said fixed outlet port (40) said metering device (2) can emit said amount, alternatively to through said second rotatable port (39) and said fixed outlet port (40).

4. Apparatus according to any preceding claim, and further comprising liquid-flow throttling means (24) arranged upstream of said fixed inlet port (36).

5. Apparatus according to claim 4, wherein said liquid-flow throttling means (24) is displaceable between an inoperative position in which it is unable to throttle liquid flowing towards said fixed inlet port (36) and an operative position in which it throttles liquid flowing towards said fixed inlet port (36).

6. Apparatus aacording to any preceding claim and further comprising an outlet chamber (6,26) downstream of said fixed outlet port (40), outlet means (38) from said chamber (6,26), and a suction-producing device (8) communicating with said chamber (6,26) at a location downstream of said fixed outlet port (40) and upstream of said outlet means (38) and arranged to produce suction in said chamber (6,26).

7. Apparatus according to claim 6, wherein said suction-producing device (8) includes a wall portion (14,115) of said chamber (6,26) movable inwardly and outwardly to reduce and increase, respectively, the internal volume of said chamber (6,26), and adjusting means (18,118) for adjusting the stroke of said wall portion (14,115).

8. Apparatus according to claim 7, wherein said suction -producing device (8) comprises a piston-and-cylinder device (8), and said adjusting means (18,118) comprises set screw means (18,118) arranged to abut the piston (15,115) of said piston-and-cylinder device (8).

9. Dosing apparatus for emitting liquid doses, comprising an outlet chamber (6,26), means (7,30) for supplying doses of liquid to said chamber (6,26) and including an inlet valve (7) to said chamber (6,26), outlet means (38) from said chamber (6,26), and a suction-producing device (8) communicating with said chamber (6,26) at a location downstream of said inlet valve (7) and upstream of said outlet means (38) and arranged to produce suction in said chamber (6,26), said device (8) including a wall portion (14,115) of said chamber (6,26) movable inwardly and outwardly to reduce and increase, respectively, the internal volume of said chamber (6,26), and adjusting means (18) for adjusting the stroke of said wall portion (14,115).

10. Apparatus according to claim 9, wherein said suction -producing device (8) comprises a piston-and-cylinder device (8), and said adjusting means (18,118) comprises set screw means (18,118) arranged to abut the piston (15,115) of said piston-and-cylinder device (8).

Drawing