The pipes are calling

Part of the backbone of any hospital laboratory - pneumatic tube delivery systems are no longer the poor relation when it comes to automation

Virtually all hospital laboratories now rely on Pneumatic Tube Systems (PTS) to deliver samples and other small payloads, and whilst the transport of samples to the laboratory is undoubtedly one of the most important aspects of the sample processing operation, in many respects PTS remain the poor relation when automation and robotic technology is considered.

For at least the last ten years, there has been a desire to introduce automation to PTS equipment to reduce the amount of manual handling of PTS carriers within busy specimen receptions. As the prevalence of larger 160mm PTS has grown, the importance of looking at ways to improve the process has increased. The problem is exacerbated by the latest installations since 160mm PTS carriers are quite large, and in busy laboratories where high volumes in excess of 50-60 carriers per hour may be received, repetitive manual handling becomes extremely onerous. Recent advances in robotic equipment have finally presented a solution and the first fully automated carrier handling robot was installed in the specimen reception at St Olav’s University Hospital in Trondheim, Norway in early 2010 where the equipment has subsequently demonstrated efficient and reliable performance.

However, automation has not been an easy nut to crack; the variability in the size and weight of payloads together with the fact that traditionally carriers have been designed only for manual handling has meant that automation solutions have had to address several facets of the PTS installation.

There are three principal aspects of the operation of processing PTS carriers that have had to be tackled to arrive at a robust and practical solution. These are the design of the carrier; the design and construction of a robotic unit for physically handling the carriers and payloads; and the implementation of new software and control systems for auditing and managing the process.

To introduce automation, carriers have to be suitable for both robotic and manual handling. The new style carriers will be familiar to anyone who is used to handling traditional swivel-lid PTS carriers; the operation of manually opening and closing the lid is almost identical to standard carriers. However, positive snap open and close springs help to ensure that the lids are operated correctly by the robotic unit, and a positioning sensor incorporated into the carrier body locates the rotational orientation of the carrier during automated handling. Finally, embedded transponders are used to interface with the control software for carrier identification.

The heart of the automation process is the robot itself. Relatively small with a footprint of 3.5m x 1.5m, the Auto Carrier Opener (ACO) robot has been developed by Swisslog Healthcare in association with Graniten Engineering; one of Scandinavia’s foremost process automation specialists.

The ACO robot connects to both multiple tube inputs and outputs and has a capacity to handle in excess of 150 carriers per hour which is more than adequate for the largest hospital specimen reception. The problem of variably sized payloads has been overcome by combining gravity extraction with a “pusher” that passes through the carrier within the robot to ensure that it is emptied correctly. In answer to users’ requests to discriminate between urgent and routine samples the robot can discharge the specimen payloads onto either of two output conveyors from which they drop straight into receiving trays.

The complete carrier handling process is automated. The carriers are received, opened, emptied, closed, transported to a return unit and automatically readdressed without any manual intervention.

Apart from the necessary mechanical systems required to automate the processing of the carriers, the transponders and sensors in the carrier ensure that the process is audited by the control software. The arriving carriers are identified using a “track and trace” system to register the arrival of specific payloads, and the carriers unique identity is also used to ensure that it is returned to an appropriate location. This could be back to a specific “home” station, or into general stock for allocation on a most-needed basis.

The enhancements introduced into the PTS control software for carrier auditing and management that have been necessary for robotic automation also benefit standard PTS installations since the transponder controlled carrier identification and auditing features can be fitted to any type of PTS station.

It is worth noting that similar robots also operate in St Olav’s within the Automated Pharmacy where drugs and other payloads are automatically loaded into the robotic “smartopen” carriers for automated despatch.

The robotic solutions that have now been operational for nearly a year in St Olav’s are the culmination of several years’ research and development. Commissioning and testing has demonstrated that automatic handling of PTS carriers is reliable, robust and efficient. With a PTS carrier opening robot now available on the market, hospital laboratories are able to easily calculate the cost and benefit of automating carrier handling compared against the manual alternatives.

In busy specimen receptions, it is usual for a significant part of many people’s working day to be taken up opening, emptying and returning the PTS carriers, therefore it can be expected that investment in robotic equipment can realise a realistically short amortisation period with the benefit increasing directly in proportion to the size and throughput of the specimen reception served.

Pneumatic tube systems might have been invented in the 19th century, but today they are more important than ever in meeting the logistics demands for small payload transportation across ever larger hospital campuses. Technological advances ensure their place as an essential part of hospital laboratory operations for many years to come.