Measuring and weighing without contact

Par­tic­u­lar­ly in clean­rooms, sur­faces must be sealed, and be able to be eas­i­ly and effec­tive­ly cleaned and dis­in­fect­ed. The items of appa­ra­tus present the biggest chal­lenge here: from test tubes to dis­til­la­tion columns, they are intro­duced from the out­side and can bring in germs. More­over, the con­tact sur­faces on their bases devel­op minute cracks that are dif­fi­cult to keep clean. The use of lev­i­ta­tion tech­nol­o­gy based on mag­net­ic fields – for exam­ple super­con­duc­tor tech­nol­o­gy – can dis­pense with such prob­lems in future.

SupraSensor: measuring and weighing without contact

One of the many pos­si­bil­i­ties is shown by the SupraSen­sor, an appli­ca­tion-ori­ent­ed exhib­it by Fes­to. It demon­strates the func­tion of a con­tact­less bal­ance, which could be used for exam­ple on ster­ile work­bench­es in bio­log­i­cal or chem­i­cal ana­lyt­ics. This con­cept allows var­i­ous phys­i­cal quan­ti­ties, such as weight, den­si­ty, vis­cos­i­ty or tem­per­a­ture, to be mea­sured using a force-based mea­sur­ing system.

An easy-to-clean laboratory environment

“In a lab­o­ra­to­ry envi­ron­ment, work­place sur­faces remain clear of appa­ra­tus and can there­fore be effec­tive­ly and eas­i­ly cleaned, since every­thing except the car­ri­er for the item to be weighed can be screened from the sur­round­ings,” explains Georg Bern­er, Head of Strate­gic Cor­po­rate Devel­op­ment, Group Hold­ing Fes­to and Project Coor­di­na­tor for the SupraMo­tion con­cepts. “Only the weigh­ing pan car­ry­ing the item hov­ers over the table top – with­out the dan­ger of cross-con­t­a­m­i­na­tion via the work­place sur­face or tools.” The entire weigh­ing appa­ra­tus can be decou­pled from the sur­round­ings with­out vibra­tion by means of a frame.
If the pan is not need­ed, it can be removed and the entire work­ing space of the ster­ile work­bench becomes avail­able. This is made pos­si­ble by a spe­cial char­ac­ter­is­tic of super­con­duc­tors: they can hold mag­nets in sus­pen­sion at a fixed dis­tance when cooled to a cer­tain tem­per­a­ture. The exhib­it thus impres­sive­ly demon­strates how a work­room and lab­o­ra­to­ry equip­ment, includ­ing sen­sors, can be cou­pled to each oth­er with­out con­tact despite spa­tial separation.

Applications in medical technology

In addi­tion to pure­ly mea­sur­ing and weigh­ing, this tech­nol­o­gy offers numer­ous fur­ther pos­si­bil­i­ties such as ana­lyt­i­cal deter­mi­na­tion of den­si­ty or vis­cos­i­ty, pre­cise meter­ing or the sur­veil­lance of reac­tive or bio­log­i­cal process­es. “The pos­si­bil­i­ty of han­dling objects with­out con­tact and thus com­plete­ly free of con­t­a­m­i­na­tion is of great inter­est above all in med­ical tech­nol­o­gy. Since no fric­tion aris­es, mea­sure­ments are not fal­si­fied and are absolute­ly pre­cise,” says Dr. Frank Jacob, Head of the LifeTech Project Unit at Fes­to. “The con­cept of the super­con­duc­tive bal­ance is now being realised in close coop­er­a­tion with one of our cus­tomers as a pro­to­type. It shows how we can con­struct easy-to-clean weigh­ing devices in future and inte­grate them into auto­mat­ed sys­tems in com­bi­na­tion with our dri­ve technology.”

Superconductors: materials with special characteristics

Super­con­duc­tors are mate­ri­als that can store the field of a per­ma­nent mag­net at a defined dis­tance below a cer­tain tem­per­a­ture. With this effect, objects can be held in posi­tion and moved free of con­tact. The lev­i­ta­tion gap remains sta­ble even beyond walls. Thanks to its restor­ing forces, the super­con­duc­tive mag­net­ic bear­ing com­po­nents autonomous­ly return to their stored posi­tions, even if one of them is tem­porar­i­ly removed – with­out the need for exter­nal reg­u­la­tion technology.