Thornton and Ross Ltd is a leading manufacturer of medicines and products for the healthcare, personal care and household markets. Recently the company began development of new pharmaceutical products to be supplied in 5-litre 'jerry can' style containers. However, because the container is rectangular and the axis of the closure is offset from the container's centreline, conventional torque testers are not suitable for measuring the release torque. Crane Electronics has now designed and supplied a bespoke baseplate for use with one of its CapStar II digital torque testers. The first new Thornton and Ross product will be a sugar water solution for use by pharmacists in the preparation of methadone. Other products to follow soon after will be purified water and methadone solution. All of these will be put in 5-litre containers that have an integral handle on the top and a tamper-evident closure offset from the container's centreline. Conventional universal fixtures that centre the container on the torque meter cannot be used, as torque must be applied to the closure when it is directly in line with the axis of the measurement transducer if an accurate reading is to be obtained.

Crane Electronics helped Thornton and Ross to overcome this problem by designing a special baseplate that mounts on the CapStar II instrument to hold the container securely in the correct position - with the closure aligned with the measurement transducer - while the operator applies a torque to the closure. The CapStar II has been mounted on a small stainless steel table that can be readily moved around the production area as required.

So far the CapStar II has only been used on the pre-production trials, during which virtually all of the containers had the closure release torque tested. Once full production has been reached, Thornton and Ross may make use of the advanced features of the CapStar II, such as its capability for performing statistical analyses on the data, and the facilities for printing the results locally and/or transmitting data to a PC via an RS 232 serial communications link.

In addition to testing closures immediately after they have been tightened, Thornton and Ross will be testing samples that have been stored for one day, one week and one month in order to check that the release torque has not dropped below the 19-22 Nm target due to the closure backing off.

Daniel Higgins, a Projects Engineer at Thornton and Ross, explains why the company chose to work with Crane Electronics: "We have a great many CapStars in use around the plant, all of which have performed extremely well over a long period. It was therefore natural that we should approach Crane when we had a container that would not fit a standard fixture. The engineer came on site straight away to discuss our requirements and then took away some sample containers. Very soon they loaned us a prototype to trial - and it worked perfectly. We therefore placed an order for a production-quality fixture and that, too, was delivered promptly. Throughout the entire project, Crane has been extremely responsive and helpful."

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