Digital oxygen valve paves the way to the future

Oxygen is the most abundant element in the Earth's crust and the second most abundant element on Earth as a whole. Without oxygen, people cannot survive, and medical professionals cannot save lives. The supply of medical oxygen requires extensive logistics and a large workforce. Linde Healthcare is one of the leading suppliers of medical gas, and in partnership with KELLER AG für Druckmesstechnik, has taken oxygen cylinder regulation to a new level.

Advanced gas supply worldwide

Linde Healthcare supplies medical gas to clinics and hospitals in more than 50 countries worldwide. When it comes to medical care, it is vital that diagnostic and therapeutic technologies operate reliably, meeting the highest standards of safety, quality, and efficiency worldwide. Gaseous oxygen is stored under excess pressure in cylinders. Medical oxygen for mobile use is generally available in cylinders ranging from two to five liters. At a pressure of 200 bar, one liter of medical oxygen is equivalent to 200 liters of oxygen at normal air pressure.

Oxygen cylinders with analog pressure gauges have been used to supply medical gas for more than 20 years. The user reads the remaining oxygen level on a physical scale and calculates it based on residual pressure, cylinder size, and the set oxygen flow. This requires a huge amount of human resources, as hospitals use up to 1000 gas cylinders every day, with each cylinder operating for about three hours when used at maximum flow rate. This colossal supply technique is carried out by the junior medical staff themselves.

Linde Healthcare came up with the idea of using a digital display on oxygen cylinders to simplify hospital logistics. The project preparation involved developing a digital valve compatible with existing robust oxygen cylinders. Linde contacted KELLER AG für Druckmesstechnik through an official project tender.

A new level of professional compliance through a comprehensive starting point

KELLER AG für Druckmesstechnik is a leading European manufacturer of pressure sensors and transmitters. Many years of experience in providing customized solutions and a willingness to take on new challenges made the company an ideal partner for Linde. For many years, KELLER has been expanding level measurement with specially designed sensors for all kinds of challenging environments. However, within the project for Linde Healthcare, KELLER made a conscious decision to take on this new challenge to further develop its internal infrastructure and technological processes for products in the medical industry.

Oxygen cylinder with analog pressure gauge

Besides ensuring compatibility with the used cylinder, no changes in the design of the new digital valve were allowed. At the same time, the sensors had to meet the high quality standards required for medical oxygen applications. To meet these standards, KELLER had to develop a completely new sensor fully adapted to the specific environment. The sensor had to be capable of measuring pressure ranges up to 300 bar and had to be manufactured in a sterile environment.

From analog to digital

To meet these strictly defined requirements, the project team tested various designs and prototypes until they found the perfect combination. The newly developed pressure sensor is very robust, reduced to the essentials, and made from materials that tolerate oxygen very well. Thanks to these qualities, the PA-5 sensor from KELLER stands out with its very compact design and is currently becoming a core component of Linde's digital oxygen cylinders.

Innovative gas cylinder system with digital display and acoustic signal

The analog sensor integrated into the valve measures the pressure of gaseous oxygen in the cylinder and transmits this information to the electronics behind the display via a detachable connection. The patient can access the following prepared data at any time using clear symbols.

Remaining oxygen and flow

  Display of remaining time with selected flow setting

  Fill level

  Current flow rate

Warning Symbols

  Critical condition

  Gas flow below set level

  Temperature too high or too low

  Low battery level

  No audible signal

  Magnetic field detected

Status

  New, unused cylinder

Along with the digital display, the valve also has audible and visual alarm signals. The alarm indicates a critical condition, such as low fill level or restricted gas flow caused by a kinked hose. When patients monitor the cylinder themselves, it provides them with greater safety.

This new and innovative gas cylinder system is called LIV® IQ (Linde Integrated Valve), and it has proven itself very well on the market. The main advantage of this system lies in the aspect of self-monitoring and better mobile oxygen delivery, for example, during patient transport. Additionally, it greatly assists medical staff, as they spend less time taking readings since they know to the minute how long the oxygen will last with the current settings.

Experience Exchange in the Field of Digital Oxygen Cylinders

Optimization of medical gas supply will go even further in the future. There are plans to develop LIV® IQ into IoT (Internet of Things). In the future, the valve's digital data will be integrated into the hospital's internal network via radio communication and prepared according to customer needs.

Junior medical staff can access all digital, audible, and visual information from any workstation in the hospital network. Again, this significantly reduces the additional effort of checking each oxygen cylinder on site.

This step towards the Internet of Things is currently being developed by Linde Healthcare. With this planning solution, the next generation of LIV® IQ will revolutionize the handling of oxygen cylinders in hospitals.

Linde Healthcare - a global division of Linde Group specializing in comprehensive artificial lung ventilation worldwide, covering everything from pharmaceutical gas supplies and medical products that go with them to patient care at home and in specialized centers. Safety, quality, and innovation in treatment and services have always been core focuses. Linde Healthcare also operates in more than 60 countries worldwide.

At KELLER AG für Druckmesstechnik , 450 people work, and the company has been producing piezoresistive measurement technologies for over 40 years. Since its founding, the company has developed custom
pressure sensors for a wide range of tasks. An important bonus is the company's great flexibility, which allows it to appropriately meet customer requests.

Bernd Ricker

Global expert in medical equipment at Linde Healthcare

«When you open up new technological possibilities, as Linde did with LIV® IQ, it is very pleasant to have the best experts on your team. When it came to pressure measurement technology, there was no doubt that KELLER perfectly meets these requirements. In our case, it is important not only that our suppliers have the necessary technical expertise but also that they are ready to offer customized solutions. And last but not least, when it comes to medical applications, only the highest quality products are acceptable. In KELLER, we have found a partner who decisively supports us in this endeavor.»

Michael Mack

Product Manager KELLER AG für Druckmesstechnik

“Thanks to close cooperation with Linde, KELLER was able to gain valuable insights into market requirements for medical oxygen at the stages of product development and launch. For example, the quality of the working environment in certain KELLER production departments has been raised to a new level. In turn, Linde was able to benefit from KELLER’s extensive experience in pressure sensor measurements, data analysis, and compensation. With the pressure sensors currently being developed, a path is being paved towards the future of intelligent oxygen cylinders.”