Machines you can count on

Accurate tablet and capsule counting is a critical step in pharmaceutical packaging halls, but before the counting can begin, the product must arrive safely and in a presentable manner at the counter.

Ensuring the correct number of tablets or capsules end up in the final pack is crucial. Overcounting can have a serious effect on a company's balance sheet, while undercounting may have disastrous consequences for the whole business. But before the counting can start, the dose forms have to reach the counting machine in one piece, presented in such a way that the likelihood of a miscount is at least minimised, and preferably eliminated. As such, one of the critical elements in tablet and capsule handling is the separation of individual products prior to counting to avoid multiples of products being recorded as a single count.

Perhaps the most simple way of achieving this is through a vibratory bowl feeder, which is effective, but not the most rapid. For high speed applications — typically the norm in pharmaceutical production — multi-channel vibratory separators feeding a counting device have become much more common.

However, the introduction of rotating disk technology now provides a further option for high output lines. This achieves separation through the use of rotating disks mounted within the main hopper. Every tablet or capsule is positively spaced in the disk, which the developer, Romaco Bosspak, says ensures separation and complete control of each one from sorting disk through to the final pack.

'This vibration free, single stream filling method, as distinct from dump filling, increases speed, most notably where larger, irregular shaped or difficult to handle products are being counted into bottles with narrow necks,' says Bosspak. It also claims the added benefits of gentle product handling and reduced dust generation.

Positive container handling is facilitated by transferring containers from a conveyor onto a central bottle starwheel set below a rotary counting turret. Each bottle is located beneath a count head, filling and counting while the bottles are rotating to maximise speed and stability. Once the correct count has been reached, the bottles are returned to the conveyor.

A major step forward in counting technology is also claimed with the introduction of an optical matrix or 'quad count'. This detects tablets or capsules around four sides of the counting head, which according to Bosspak, 'increases the count zone by 100% compared with conventional counters'. Most broken or chipped products can also be detected.

An integrated touch screen control panel allows straightforward programming, storage of set-up parameters and the collection of statistics for batch reconciliation. A dust extraction system dedusts before counting and filling. The machine also has an integral single bin elevator and on-demand feed system which is said to reduce dust generation, accelerate cleaning and contribute to the overall compact footprint. Tool-free changeover also reduces downtime.

The RTC range is said to combine speeds previously achieved only by slat counters — the 12-station 200 model has an output of up to 200 one-hundred count bottles/min — with the flexibility and control of an electronic system. On difficult shaped products such as caplets and soft gel capsules, Bosspak says the RTC 'can far exceed the speeds normally associated with vibratory machines'.

Newly introduced is a single station standalone model, the RTC 15. Available in semi- or fully-automatic execution it has an output of up to 15 bottle/min and additional stations can be added to increase output as required. It is said to be ideal for small batch production, operator training and benchtop applications, such as the laboratory.

Bosspak says the RTC 15 can also complement high throughput, in-line counters. For QC purposes, it can be used off-line to verify count accuracy and for existing RTC 200 users it can improve productivity by allowing new formats to be optimised off-line.

continuous feeding

The Italian manufacturer Iman Pack has also employed a continuous feed method in its new tablet and capsule counter, which utilises technology adapted from the company's established range of hardware and parts counting machinery.

The low-cost MVR4 counter, intended for mid-speed range duties — up to 2,000 items/min, for typically 20-40 containers/min — is PLC controlled and equipped with the usual vibrating feed tracks on which frequency and amplitude are adjustable to suit the weight and shape of items to be counted.

However, unlike traditional tablet counters which feed into delivery hoppers that open intermittently to discharge a complete count, the Iman Pack machine feeds continuously directly into the container past fibre-optic photocells that establish the count. Once the count is completed, the product flow is simply diverted back to the feed tracks until the next count commences.

'This method has been proved in machinery for counting hardware such as screws, nuts and bolts over many years,' says Tony Dunleavy of UK agent Sussex & Berkshire Machinery. 'It means that the new MVR4 has fewer moving parts than traditional tablet counters and therefore lower build and maintenance costs, as well as being faster to clean'.

Following 18 months of development work, two new versions of Electro-mec's EMF tablet and capsule feeder have been introduced and 'continuous' is again the theme, as these models have been introduced to operate in conjunction with the latest generation of continuous motion blister packaging machines.

The EMFC operates on the same principles as the existing EMF range for intermittent blister packers, using individual feed tubes to dose a single tablet into each blister form per cycle. However, whereas for intermittent machines the web is static when the blister receives product, with the EMFC range, tablets and capsules are dispensed from a moving slide that synchronises its speed with the speed of the moving web.

The company says that the success of the system is down to the servo motor, which controls the dispensing system and is linked directly to an encoder installed within the machine's drive system. This direct communication means the feeder always knows the exact status of the web at any given time and can adjust its speed immediately to keep pace with the packing sealing operation.

Two versions of the new range are offered: the EMF1C has been designed to cope with standard sizes and types of tablets and capsules, while the EMF2C incorporates additional features such as awkwardly shaped tablets or those that are prone to chipping and shingling.

The key innovation is said to be the incorporation of an additional 'holding' gate at the base of the feed tubes. With the EMF1C, the entire fed tube system moves along the web. For gentler handling of more difficult product, the EMF2C has a separate final feeding system, and only this part moves along the web, with the holding gate controlling entry of product into this section.

intelligent scrutiny

Turning to pure counting technology, DT Swiftpack says its machine breaks the mould of electronic inspection counters by introducing intelligent scrutiny at the point of count. Using an electrostatic field, the SV2 Intellisense is said to deliver an extremely accurate assessment of a range of tablet parameters — including size, shape and weight — and measures each against all parameters as it falls through the field. Any product varying from the pre-determined parameters is rejected.

This latest generation of counters differs from the company's traditional technology which operates an infra-red system to count each tablet and assess given shape by calculating the time it takes to pass the sensors.

Swiftpack says that, previously, counters were able to check product by shape only, any empty hard gelatin capsules, for example, were counted as correct. Similarly, although badly damaged tablets could be detected by infra-red systems, those with a slight chip or small variance in thickness from the norm could get through.

As the electrostatic technology has the capability to check weight and detect minor physical variances, the company says it provides an accurate measure of product quality in terms of physical variance. 'The new Electrostatic Sensing System adds intelligence and QC to the final package from manufacturers,' it says. 'Already, QC is built into process, production, pre-packaging and post-packaging. Now manufacturers can achieve continuous QC throughout the manufacturing process. There is nothing comparable with the Electrostatic Sensing System in the marketplace.'

higher GMP specification

The counter itself has been redesigned too, Swiftpack claiming a higher GMP specification with improved dust control and quick release fasteners to ease cleaning and maintenance.

Enclosed pipework and cabling also facilitate clean operation. Changepart requirements are minimal as a larger count head not only enables more product to be held in the pre-count, thus improving productivity, it also accepts products of different sizes. Depending on customer requirements, it can be fitted with either the new electrostatic system or traditional infra-red technology.

The IMA Precisa 120 checker can be integrated into the line to give 100% checking of tablets and capsules. The device accepts the dose forms directly from the production machine and transports them to a set of weighing cells, where every capsule is checked and the results fed into the unit's computer. After weighing, any out-of-specification products are ejected while the accepted product carries on to the packaging lines.

The unit uses a drum fitted with suction holes to hold the product as it rotates, and position them onto the weighing cells. One company that is using the machine is Clinical Trial Services in Craigavon, UK. Intended to cut lead times for its contract packaging operation, it has increased capacity from 50,000 capsules/day to over a million.

small footprint feeder

To facilitate the transport of product to packaging lines, the German manufacturer of tablet and capsule sorting and handling equipment, Ottenschlaeger, has introduced a feeder only version of its Sortlift 8. The Feedlift 8 vertical feeder — available in the UK through F.J. Pistol — is a high capacity, small footprint feeder capable of feeding different output heights up to 2.3m in standard format. Custom units can be made for higher output levels.

Major players back blistering success of EMF technology

Two major pharmaceutical companies have recently backed Electro-mec's EMF technology with the installation of machines for feeding capsules and tablets to blister pack lines. Eli Lilly has installed an EMF1 over an Uhlmann UPS300 blister machine to pack a Prozac line for hospitals at its Basingstoke plant and says the feeder has provided ‘the ideal packaging solution". Its individual feed tubes are positioned over each blister ensuring that every capsule is placed directly into the form to avoid missed blister rejects. At the same time, this method ensures the product is handled gently, thus reducing the risk of breakages. ‘Over the years, Electro-mec has consistently proved to be an extremely good supplier and we continue to use them for our tooling requirements", says Eli Lilly packaging technologist, Brian Scott. ‘They understand our particular needs and respond quickly in the design and production of tooling". Meanwhile a special version of the EMF feeder has been developed for Boots Contract Manufacturing which enables the company to alternate between different filling methods depending on the product being packed. The EMF4X has been specified for use with Boots" Senna-based range of tablets. These are dry, dusty and difficult to handle products, and therefore ‘require the gentle, precise placement of the EMF which uses its unique individual feed tube layout to dose each tablet into the blister to ensure accurate and efficient filling with no product damage", says Electro-mec. However, the EMF4X also features a flood box interface which enables the feeder tube layout to be removed and a flood box with paddles to be inserted in its place. Converting between the systems is said to be easily effected, minimising line changeover time. ‘With the EMF4X we have the best of both worlds", comments Ray Whalley of Boots. ‘It provides the gentle, accurate filling required of our senna-based tablets and also the faster throughput of free-flowing coated products".