GB2304526A - Rod smpler and method. - Google Patents

Abstract

The present invention relates to a rod sampler [20] for providing a sample rod which comprises a sample inlet [18] and a sample holding zone [24] separated by a valve [22] which is moveable between a first position in which a sample rod can pass longitudinally through the valve [22] from the inlet [18] to the sample holding zone [24] and a second position in which the valve [22] pneumatically isolates the sample holding zone [24] from the inlet [18], and means for pneumatically transporting a sample in the sample holding zone longitudinally therefrom.

Description

ROD SAMPLER AND METHOD The present invention relates to a rod sampler and method of sampling a rod, in particular a rod sampler and sampling method for cigarettes or cigarette filter rods.

When manufacturing cigarettes and cigarette filter rods (e.g. integral sextuple length filter rods, which are subsequently cut into individual filters) it is important that random samples are tested for the required quality and performance, for example weight, length, diameter, uniformity, density, pressure drop, etc. It is important that samples may be removed during manufacture, such as from a production line, e.g. from a mass flow, and transported to a test site without interruption of the manufacturing process.

According to the present invention there is provided a rod sampler for providing a sample rod which comprises a sample inlet and a sample holding zone separated by a valve which is movable between a first position in which a sample rod can pass longitudinally through the valve from the inlet to the sample holding zone and a second position in which the valve pneumatically isolates the sample holding zone from the inlet, and means for pneumatically transporting a sample in the sample holding zone longitudinally therefrom. The present invention can thus provide a sampler which is more compact than previous samplers, and which can transport sampled rods to a destination, such as a test site, at high speeds without the need for heavy duty valves, pipes or other large pneumatic apparatus.For example, the valve used in the sampler of the present invention may have outside dimensions the order of 50 mm x 60 mm, with a bore the order of 10 mm diameter.

References herein to "pneumatic" do not limit to the use of air as operating gas; any suitable gas may be used.

Positive pressure or partial vacuum (suction) may be used to effect pneumatic transport.

The valve used in the rod sampler of the present invention is preferably an at least 2-way valve. Preferably the valve in the second position provides a conduit which connects the pneumatic transport means and the sample holding zone. The valve is preferably actuated pneumatically.

The valve is preferably rotated between first and second portions by a pneumatic reciprocal rotary actuator. The valve is suitably a ball valve.

The sampler of the present invention preferably further includes a sensor for detecting the emergence or non-emergence of a sample from the valve to the sensor and the clearance or non-clearance of a sample past the sensor into the sample holding zone. Under normal operating conditions the emergence of each sample from the valve to the sensor will be detected, as will its clearance past the sensor to the sample holding zone after which the next stage in the operating sequence will commence. If non-emergence of a sample from the valve is detected, for example due to a fault or at the end of a testing run, the next step in the operating sequence will be postponed and the operating sequence will restart in a second attempt to introduce a sample through the inlet into the sampler after which the next stage in the operating sequence will commence.If non-emergence of a sample is detected after this first restart a predetermined number of further restarts will be made after which if non-emergence is still not detected a fault will register and the sampler operation will shut down. If emergence of a sample from the valve to the sensor has been detected but non-clearance from the sensor to the sample holding zone is also detected, for example if a sample is stuck in the valve, the next step in the operating sequence will be postponed and a second attempt will be made to clear the sample from the sensor to the sample holding zone. If non-clearance is still detected after the first reattempt at clearance, a predetermined number of further reattempts will be made after which if non-clearance is still detected a fault will register and the sampler operation will shut down.

The present invention can further provide, in combination with the rod sampler of the present invention, a sample probe for receiving a sample rod for conveyance to and through the inlet of the sampler, the sample probe comprising concentric inner and outer sleeves each having a longitudinal opening and being axially relatively rotatable to bring the openings into at least partial register for accepting a sample rod therethrough to rest within the inner sleeve and fully out of coincidence form a substantially closed cylinder within which an accepted sample rod can be enclosed, and conveying means connected to the cylinder for conveyance of a sample therein to and through the inlet, and valve of the sample holding zone.

The conveying means of the sample probe is preferably pneumatic; for example it may comprise a supply of compressed air connected to the cylinder by conventional means to push a sample therefrom, or may comprise a vacuum pump similarly connected to the cylinder to pull a sample therefrom.

Preferably the inner sleeve and outer sleeve of the sample probe are relatively axially rotatable by a rotary actuator, e.g. with the inner sleeve fixed and the outer sleeve rotatable thereby. A preferred rotary actuator comprises a reciprocally rotatable main gear which is engageable either directly or indirectly via a second gear with a sleeve gear circumjacently attached to the rotatable sleeve. In this way the rotatable sleeve is axially rotatable in either clockwise or anti-clockwise directions according to whether the sleeve gear is directly engaged by the main gear or indirectly engaged via the second gear.For example, when the sample probe is placed within a mass flow of sample rods for acceptance of a sample therefrom it is desirable for the direction of closure of the rotatable sleeve to be the same as the direction of the mass flow to avoid entrapment of samples between the sleeves of sleeve closure, and thus the sample probe can cater for reversal of mass flow direction with only minor adjustment. The main gear may be moveable between a position where it can engage the sleeve gear and a position where it can engage the second gear within a guide or slot.

The rotary actuator is preferably spring-loaded so as to be resiliently biased against the direction of closure of the rotatable sleeve. This feature provides a safety measure in that an item, for example a sample or finger, caught between the outer and inner sleeves on sleeve closure should not suffer significant damage but should merely be trapped therebetween until release (unlike a pneumatically operated actuator which could cause severe damage to samples or personal injury). The bias of the rotary actuator may be changed to suit different conditions or samples by changing the spring for one of greater or less tension, and the degree of rotation of the main gear and hence the rotatable sleeve, for example substantially a right angle, may be limited by a stop. The actuator is suitably electromagnetic.

Preferably the circumferential orientation of the sleeve openings is adjustable by disengagement of the sample probe from the sampler, circumferential reorientation of the sample probe and hence the sleeve openings and reengagement of the sample probe in the reoriented position by re-engaging the sleeve gear with the main gear or second gear as appropriate.

When receiving sample rods from a mass flow the preferred circumferential orientation of the sleeve openings is downstream, for example 30 degrees to the vertical; the "current" of sample rods in the mass flow is disturbed by the sample probe creating an eddy in sample rod flow at the downstream side of the probe and thus allowing sample rods passing over the sleeves to drop into the sample probe with higher probability than if the sleeve openings were facing upstream or vertically. The degree of circumferential orientation down-stream from the vertical may be adjusted according to sample rod diameter.For example, for sample rods of small diameter the openings may be oriented at a greater angle from the vertical than for sample rods of larger diameter; the greater the angle from the vertical the smaller the vertically facing component of the opening width and hence the lower the probability of more than one small diameter sample rod passing into the sample probe.

The opening width "seen" by the sample rods in a mass flow may also be adjusted by adjusting the relative orientations of the inner and outer sleeves at rest so that the sleeve openings are not fully registrable by rotation of the outer sleeve by the rotary actuator. Alternatively, the degree of rotation of the outer sleeve may be restricted by employing a stop (see above) or for fine adjustment by turning the rotary actuator within the guides or slots.

It is to be clearly understood that although the sample probe is preferably used in combination with the rod sampler of the present invention it is not limited to use therewith and that the sample probe with any one or more of the preferred features thereof described above is inventive per se and is included within the scope of the present invention.

The present invention further provides a method for providing a sample rod which comprises longitudinally conveying a sample rod from a sample inlet through a valve in a first position to a sample holding zone, moving the valve to a second position in which the sample holding zone and sample therein are pneumatically isolated from the inlet, and pneumatically charging the sample holding zone to longitudinally transport the sample rod therefrom.

Preferably the removing and conveying steps of the method of the present invention comprise passing a sample rod through at least partially registered longitudinal openings in concentric inner and outer sleeves so that the sample rod rests within the inner sleeve, axially relatively rotating the sleeves to form a substantially closed cylinder within which the sample rod is enclosed, and conveying the sample from within the sleeves through the sample inlet and valve to the sample holding zone.

The sample is preferably conveyed from within the sleeves through the sample inlet pneumatically.

In its second position the valve, for example a ball valve, preferably simultaneously isolates the sample holding zone from the receiver and provides a conduit via which the sample holding zone is pneumatically charged.

In a first operating sequence of the rod sampler, a first sample rod is received (e.g. from a production line) and longitudinally conveyed through the inlet and valve in the first position to the sample holding zone. The valve is then moved to the second position pneumatically isolating the sample holding zone and sample therein from the inlet, and the sample holding zone is then pneumatically charged to longitudinally transport the sample therefrom. The valve is then returned to the first position and a second sample rod is received and longitudinally conveyed through the inlet, and the sequence is repeated.

In a second operating sequence, when the first sample is being longitudinally transported from the sample holding zone a second sample is simultaneously being received, so that when the valve returns to the first position the second sample can be longitudinally conveyed through the inlet and valve without delay. Thus, this second sequence can receive and transport sample rods with greater frequency than the first sequence.

The appropriate mode of operation of the rod sampler will depend on the particular sampling circumstances. For example, in circumstances where sample rods are being removed from a production line for testing, for maximum efficiency the time taken from removal of a sample from the production line to arrival at the test site should equal the time taken to test a sample, and the operating sequence should be chosen accordingly.

For operation of the rod sampler at optimum efficiency, the rod sampler components, for example valve and pneumatic transport means, may be synchronised using appropriate hardware and software, together with the sample probe components when in combination therewith , for example sleeve axial relative rotation means and pneumatic sample conveying means.

When a sensor is employed as described above, detection by the sensor of sample presence and clearance will trigger the subsequent operations of the rod sampler described above, i.e. the valve will be moved to the second position, etc.

Thus, the operation sequence of the rod sampler and combination of rod sampler and sample probe can be controlled, as can any appropriate delays and other timing operations required.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which FIGURE 1 is a plan view of a combination of a rod sampler and sample probe according to the present invention; FIGURE 2 is a side view of the combination of Fig.l; FIGURES 3a and 3b show said first and second positions of the ball valve used in the present invention; The sample probe [2] of the combination illustrated in Figs.l and 2 comprises inner [4] and outer [6] sleeves and an air-inlet [8]. The inner [4] and outer [6] sleeves both have longitudinal openings (not shown) of sufficient width and length for a sample rod to pass therethrough.The opening of the inner sleeve [4] is angled towards the viewer of Fig.l (i.e. downstream in a mass flow of sample rods) and the outer sleeve [6] is rotatable about the inner sleeve [4] such that when the opening of the outer sleeve [6] is brought into coincidence with the opening of the inner sleeve [4] an opening is formed in the sample probe [2] through which a sample rod can drop.

The outer sleeve [6] is rotatable using a reciprocal rotary actuator [10] having a main gear [12] which engages sleeve gear [14] circumjacently attached to outer sleeve [6].

A second gear (not shown) is positioned laterally of and engages the sleeve gear [14], although in the embodiment shown in Figs.l and 2 the main gear [12] engages the sleeve gear [14] directly and the second gear (not shown) does not actively participate in axial rotation of the outer sleeve [6]. Thus, looking towards the main gear [12] from the air inlet [8], if the main gear [12] is rotated clockwise using rotary actuator [10], sleeve gear [14] and hence outer sleeve [6] are rotated anti-clockwise.

The rotary actuator [10] is slidably engaged by slots [16] so as to be laterally moveable from the illustrated position in which it engages the sleeve gear [14] directly to a position in which it engages the second gear (not shown) which in turn engages the sleeve gear [14], and turnable within the slot for fine adjustment of outer sleeve rotation.

In the latter arrangement, clockwise rotation of the main gear [12] causes clockwise rotation of sleeve gear [14] and hence outer sleeve [6].

The sample probe [2] is threadedly engaged with inlet [18] of rod sampler [20]. The rod sampler [20] further includes a 2-way ball valve [22] which is movable between a first position (shown in Fig.l and Fig.3a) in which a sample rod can pass longitudinally therethrough from the sample probe [2] and inlet [18] and a second position (shown in Fig.3b) in which it simultaneously pneumatically isolates sample holding zone [24] from inlet [18] and provides a conduit through which air may be injected from a source of compressed air (not shown) via air inlet [26]. The sample holding zone [24] forms part of a transport tube (not shown) along which sample rods are longitudinally transported from the sample holding zone [24] in the direction of arrow A towards a test site.

The ball valve [22] is moved between said first and second positions by reciprocal pneumatic actuator [28].

The rod sampler further comprises a sensor [30] which detects the emergence or non-emergence of a sample rod from the ball valve [22] and the clearance or non-clearance of a sample rod past the sensor [30] to the sample holding zone [24]. The consequences of the sensor [30] detecting absence and/or non-clearance of a sample are discussed below.

A first operating sequence of the combination of sample probe [2] and rod sampler [20] shown in Figs.l and 2 is as follows: 1). Rotary actuator [10] is activated rotating outer sleeve [6] (via main gear [12] and sleeve gear [14]) and bringing the outer sleeve longitudinal opening (not shown) into reference with the inner sleeve longitudinal opening (not shown) to create an opening in sleeves [4] and [6].

2). A sample (e.g. a filter cigarette or integral sextuple length filter rod) passes through the opening to rest within inner sleeve [4], and, a predetermined time after stage 1 above (e.g. 2 seconds), outer sleeve [6] is rotated back to its previous position, bringing the longitudinal openings (not shown) out of coincidence thereby enclosing the sample within the sleeves [4] and [6], which now form a substantially closed cylinder.

3). A compressed air source is activated and air is injected through air inlet [8] thereby conveying the enclosed sample along the sample probe [2] and through inlet [18) and ball valve [22] in a first position (as shown in Fig.l and Fig.3a) to sample holding zone [24]. Sensor [30] has by now detected both the emergence and clearance of the sample which triggers step 4 below, and consequently the operating sequence will continue.

4). Pneumatic actuator [28] is activated and ball valve [22] is moved to a second position (as shown in Fig.3b) pneumatically isolating the sample holding zone [24] and sample therein from the inlet [18], and a compressed air source is activated and injects air through air inlet [26] and ball valve [22] into sample holding zone [24] pneumatically transporting the sample therein therefrom in the direction indicated by arrow A.

5). The sample arrives at its destination, e.g. a test site.

Typical transport time -up to 10 seconds (e.g.

approximately 8 seconds) for 50 metres of transport tube.

6). Pneumatic actuator [28] is activated (triggered when the sample rod has reached its destination) moving ball valve [22] from the second position back to the first position, and rotary actuator [10] is activated to rotate outer sleeve [6] as in step 1 above to restart the sequence.

A second operating sequence of the combination of sample probe [2] and rod sampler [20) initially follows steps 1 to 4 above.

However, while the sample is being transported to its destination (i.e. between steps 4 and 5 above) steps 1 and 2 above are repeated to enclose a second sample within the sleeves [4] and [6]. When the first sample reaches its destination (step 5 above) and the ball valve [22] is returned to the first position (step 6 above), a second sample is already enclosed within the sleeves [4] and [6] and the sequence can proceed from step 3 above. Thus, in the second operating sequence a second sample is enclosed within sleeves [4] and [6] ready to be conveyed through inlet [18] when ball valve [22] is returned to the first position, thereby allowing samples to be transported to their destination with greater frequency than by the first operating sequence.

It is important that the operating sequence steps described above are correctly timed and the various sample probe [2] and rod sample [20] apparatus are properly synchronised to attain optimum efficiency. This is achieved using appropriate hardware and software to control the rotary actuator [10], pneumatic actuator [28] and compressed air sources (not shown); the hardware is programmed to ensure apparatus is switched on and off at the correct points in the operating sequence, and to insert the appropriate delays into the operating sequence (e.g. the length of time allowed for a sample to pass between the openings in the sleeves [4] and [6], and the length of time for which the ball valve [22] remains in the second position to allow a sample to reach its destination).

The operating sequence of the sample probe [2] and rod sampler [20] is triggered by external control, such as the above-mentioned control hardware and software. If the sensor indicates that no sample has emerged from the ball valve [22], or that a sample has emerged but its clearance past the sensor [30] to the sample holding zone [24] is incomplete then no further signal is sent and the subsequent operations are postponed.

In normal operation, a sample is enclosed within sleeves [4] and [6] and compressed air is injected through air inlet [8] to convey the sample through inlet [18] and ball valve [22] in the first position to sample holding zone [24]. If these operations are performed but emergence of a sample from the ball valve [22] is not detected by the sensor [30], a signal is not sent to the control system. Compressed air is then reinjected through air inlet [8] a predetermined number of times, e.g. three times, in case a sample is enclosed within the sleeves [4] and [6] but was somehow not conveyed through the inlet [8] and ball valve [22] to the sample holding zone [24] by injection of compressed air through inlet [8] during the normal operating sequence.If after this sequence the emergence of a sample from the ball valve [22] has still not been detected steps 1 and 2 above are repeated thus restarting the operating sequence. If the presence of a sample is still not detected after the restart, compressed air is again injected through air inlet [8] a predetermined number of times and further restarts of the operating sequence are made in an attempt to convey a sample through the ball valve [22] to the sensor [30]. If emergence from the ball valve [22] has not been detected after a predetermined number of restarts, e.g. three restarts, the operating sequence is shut down. If emergence of a sample from the ball valve [22] is detected at any point during the restart sequence then the sensor will send the trigger signal and the operating sequence will continue as normal.

If emergence of a sample from the ball valve [22] to the sensor [30] has been detected but its clearance from the sensor [30] to the sample holding zone [24] is incomplete, no trigger signal is sent by the sensor [30) to the control system, and the operating sequence is postponed. Compressed air is reinjected a predetermined number of times through air inlet [8], e.g. 5 times, in an attempt to shift a sample which may have jammed within the ball valve [22] or for some other reason has not cleared the sensor [30]. If after the predetermined number of injections of compressed air clearance of the sample past the sensor [30] to the sample holding zone [24] has still not been detected then the operating sequence will shut down to allow for the cause of the fault to be determined.

Claims (15)

CLAIMS:

1. A rod sampler for providing a sample rod which comprises a sample inlet and a sample holding zone separated by a valve which is moveable between a first position in which a sample rod can pass longitudinally through the valve from the inlet to the sample holding zone and a second position in which the valve pneumatically isolates the sample holding zone from the inlet, and means for pneumatically transporting a sample in the sample holding zone longitudinally therefrom.

2. A rod sampler according to claim 1 wherein the valve is a 2-way valve.

3. A rod sampler according to claim 1 or 2 wherein the valve in the second position provides a conduit which connects the pneumatic transport means and the sample holding zone.

4. A rod sampler according to any preceding claim wherein the valve is a ball valve.

5. A rod sampler according to any preceding claim which further includes a sensor for detecting the emergence or nonemergence of a sample from the valve and the clearance or nonclearance of a sample past the sensor into the sample holding zone.

6. In combination with a rod sampler according to any preceding claim, a sample probe for receiving a sample rod for conveyance to and through the inlet of the rod sampler, the sample probe comprising concentric inner and outer sleeves each having a longitudinal opening and being axially relatively rotatable to bring the openings into at least partial register for accepting a sample rod therethrough to rest within the inner sleeve and fully out of coincidence to form a substantially closed cylinder within which an accepted sample rod can be enclosed, and conveying means connected to the cylinder for conveyance of a sample therein to and through the inlet and the valve to the sample holding zone.

7. A method for providing a sample rod which comprises longitudinally conveying a sample rod from a sample inlet through a valve in a first position to a sample holding zone, moving the valve to a second position in which the sample holding zone and sample rod therein are pneumatically isolated from the inlet, and pneumatically transporting the sample rod longitudinally from the sample holding zone.

8. A method according to claim 8 wherein the removing and conveying steps comprise passing a sample rod through at least partially registered longitudinal openings in concentric inner and outer sleeves so that the sample rod rests within the inner sleeve, axially relatively rotating the sleeves to form a substantially closed cylinder within which the sample rod is enclosed, and conveying the sample rod from within the sleeves through the sample inlet and valve to the sample holding zone.

9. A method according to claim 8 or 9 wherein a second sample rod is received for conveyance from the inlet simultaneously with a first sample rod being longitudinally transported from the sample holding zone.

10. A method according to claim 8, 9 or 10 wherein the valve in the second position simultaneously pneumatically isolates the sample holding zone from the inlet and provides a conduit via which the sample holding zone is pneumatically charged.

11. A method according to any one of claims 8 to 11 wherein the valve is a 2-way valve.

12. A method according to any one of claims 8 to 12 wherein the valve is a ball valve.

13. A rod sampler substantially as hereinbefore described with reference to the accompanying drawings.

14. A combination of a rod sampler and sample probe substantially as hereinbefore described with reference to the accompanying drawings.

15. A method for sampling a rod substantially as hereinbefore described.