Breathing Deeply with Diaphragms

Diaphragms from Freudenberg Sealing Technologies (FST) handle vital tasks in medical technology and occupational safety, in everything from intensive care units to firefighting. Maximum precision is required in medical technology labs.

You shouldn’t get claustrophobic when you lie down on a flat bed and are pushed “into the tube.” In human medicine, the illumination of organs and/or joints with computer tomography (CT) provides images of ailments and is a foundation for targeted treatment. One of the leading manufacturers of three-dimensional scanners has been a customer of the Lead Center (LC) Diaphragms in Reichelsheim for years.

“We provide volume-compensating diaphragms that, in simple terms, operate like a balloon,” said Daniel Uhl, Manager, Product Marketing at LC Diaphragms. When the scanning heads recording images of your body rotate around it, the oil around them heats up. It also expands and the oil pressure rises. The diaphragms absorb the extra volume and even out the pressure, keeping lines from bursting and the patient safe from a surge of hot oil. “Our diaphragms for computer tomography qualify as safety-relevant products,” said Jolanthe Tekin, Product Marketing.

This type of diaphragm is just one example of a component chalking up wins for the Lead Center. The business trend has been stable for years, although new orders were added on short notice during the COVID-19 pandemic. Units of the Special Sealing Division responded quickly and flexibly. Recall the order from Dräger for diaphragms for pulmonary ventilators. Diaphragms “made in Reichelsheim” are the first choice for anesthesia devices manufactured by the medical technology company. (See box “Not Just Clean But Pure.”)

At the Patient Interface

FST has also been a long time supplier to a Swiss-based manufacturer of ventilators for intensive care units. “Respirators are connected to the ventilator with a tube. Inside the respirator, our diaphragms control the air feed to the patient,” Uhl said. During exhalation, the diaphragm closes the valve and enables patients to breathe out into the ambient air.

As is so often the case in medical technology, the real know-how is in the details. A special RFN coating applied in Reichelsheim ensures that the silicone diaphragm doesn’t stick in the valve if it has not been used for a while. After all, it has to resume flawless operation at the first breath. The acronym RFN stands for Reduced Friction by Nanotechnology. Diaphragms are also used in autoclaves to sterilize objects. They have yet another critical application as well. They are used in magnetic valves that regulate the breathing of premature and newborn infants.

Another example from the medical lab: ­Everyone is familiar with PTFE coatings, widely known as Teflon, from the pans on kitchen stoves. FST uses Teflon in delicate diaphragms that provide exact dosing of minuscule quantities of fluid – sometimes less than a milliliter per minute in the precision pumps used in diagnostic devices. They require the maximum precision in diaphragm production. The PTFE layer protects the rubber from the chemicals used in lab analyses. These kinds of vacuum or dosing pumps are part of the Lead Center’s core business.

Working Safely

Diaphragms also have lifesaving functions that are important for occupational safety. In respirator masks, they protect firefighters from the hazards of smoke inhalation. Much like medical respirators, the diaphragm sits in the mouthpiece and controls inhalation and exhalation. “The material is extremely flexible at low temperatures. The compressed air immediately cools as it flows out. In addition, the walls are extremely thin. Each individual diaphragm is inspected with a magnifier before shipment,” Uhl said. Safety is the top priority: Respiratory masks used in paint shops depend on FST diaphragms and offer another form of health protection. Professional divers are also supplied with breathing air via FST diaphragms.

One of the Lead Center’s new developments is especially in demand among factory fire teams and in disaster management. They not only protect first responders against injuries from smoke inhalation – they have CBRN applications as well. The abbreviation stands for chemical, biological, radiological and nuclear hazards. Dangerous, noxious gases can be produced during fires in chemical plants, diffuse through rubber diaphragms, and unleash their toxic, corrosive effects. “That’s why we developed a special material for these gas masks: an NRBR blend that combines the properties of two types of rubber,” Uhl said. The development is already in series production.

Not Just Clean but Pure

Isofluran, sevofluran, desfluran – anyone who has ever had to undergo an operation has likely inhaled one of these gases. They are three of the popular inhalation anesthetics. In anesthetic equipment, they are stored in liquid form in color-coded containers and are vaporized into the required amounts when needed. Diaphragms send the gas into the lungs along with fresh air and then out again. Diaphragms from Reichelsheim are used in equipment from the medical technology firm Dräger for both the “in” and the “out” action. The company also uses elastomer formed parts and O-rings from Freudenberg Sealing Technologies (FST) in its devices.

“This is a critical and demanding application. In the operating room, you need 100 percent functional reliability and leak-tightness,” said Marcus Starke, Global Key Account Manager, Sales General Industry.

The same applies to FST parts used in pulmonary respiratory devices, like the ones in great demand at the start of the COVID-19 pandemic. The materials inside them must meet extremely high standards. “Cleanliness requirements are another key issue. The customer expects particle-free parts from us,” Starke said.

FST ensures this in different ways. In Kufstein, the parts are washed, inspected and then washed again. They are then packaged immediately. In Oberwihl, many O-rings are “funneled” through a cleanroom that meets international standards and then are shipped as “clean pack items.”