Proportional valves with piezo technology in medical technology

Proportional valves with piezo technology in medical technology
Precisely mixing and dosing gases plays a decisive role in many areas. The most important factor is exact and reproducible pressure regulation and flow control. Piezo valves are small, lightweight, extremely precise, very durable, incredibly fast and above all save energy, making them perfect for this task.

You develop high-end medical technology. You expect solutions that meet your specific needs. We deliver customised and value-adding solutions.

More information on piezo valves in medical technology and laboratory automation at: www.festo.com/medtech
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More information on proportional valves for factory and process automation at: www.festo.com/proportional-valve

In focus

Festo is opening up a host of options for you With a choice of various valve series with different working pressures, nominal widths, flow rate ranges and working temperatures, Festo offers you the optimal proportional valve for your needs. When you have special requirements, we can adapt the valves completely to your individual needs. Just ask us!
Your objective: a competitive edge thanks to innovation Medical devices, too, are subjected to fierce and tough competition. The trends are moving towards ever smaller and lighter devices. At the same time, they have to be more cost-effective than previous models and withstand the stress of being used on a daily basis for long periods of time. The market also demands faster and more precise analytical devices as well as state-of-the-art medical equipment.
Our contribution: unique automation solutions with piezo technology Festo is the world’s leading supplier of electric and pneumatic automation technology. In close cooperation with customers, Festo automates motion and sequences for factory, process and laboratory automation as well as for medical devices. Piezo technology is one of several key technologies used by Festo for the efficient control of gas flows in medical devices.
Individually adapted – proportional valves with piezo technology from Festo

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2/2-way proportional valve VEMR, VEAE
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3/3-way proportional valve VEMC, VEMP, VEA1
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E-Box VAVE-P
Pressure and flow regulator VEMD, VEAA/VEAB
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Mode of operation

Flow control: 2/2-way valve The piezo valve has one bender and two ports. The more voltage is applied, the further it opens.

This is how piezo technology works Festo uses the piezoelectric characteristics of certain ceramics that mechanically deform when a voltage is applied.
Bender actuator with p­ iezoceramics
Off

Pressure regulation: 3/3-way valve The piezo valve has two benders and three ports. A complete pressure regulation system can be set up with this compact solution. There’s one bender for pressurisation and a second one for exhausting. The third state is closed, thus maintaining the pressure.

Passive conductive carrier
Contraction On

Function of the bender actuator in piezo valves

Bending

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Benefits of piezo technology

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Low energy consumption – no heat generation In comparison to solenoid valves, proportional valves with piezo technology require virtually no energy to maintain an active state, thanks to their capacitive principle. The piezo valve operates like a capacitor: it needs current only at the start in order to charge the piezoceramics. No further energy is needed to hold its state and it therefore generates no heat. Piezo valves consume up to 95% less energy than solenoid valves, which permanently require an electrical current.

Current [I]

Control start

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Piezo valve
No operating noise Proportional valve with piezo technology are quieter than solenoid valves – the bender actuator moves freely, without any impact noise. In addition, there is no need for pulsewidth modulation which controls the flow rate of a solenoid valve.

Time [t] Solenoid valve

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Long service life Gas flows can be regulated proportionately with proportional valves. Their design makes them wear resistant and capable of achieving an unusually high number of cycles.

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Small installation space and light weight As the piezo valve has no solenoids or electrical coils, its design is light. That, combined with its compact size, makes it ideal for installation in mobile devices.

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High level of safety Proportional valves with piezo technology are characterised by their high level of intrinsic safety, because they can maintain the current state for a while even if there is a power failure.

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Piezo technology in medical technology applications
Improved quality of life for patients and their surroundings Proportional valves with piezo technology are suitable for a huge variety of applications in medical technology. Thanks to their compact design and low power consumption, they are ideal for installation in battery-operated devices.
Mobile ventilator breathing devices • Portable oxygen system devices (oxygen conserver and
concentrator) for people with chronic respiratory ailments • Clinical and mobile ventilator breathing devices • PAP devices for patients with sleep apnoea Oxygen/ventilation therapy • Regulating gas flows and pressures Ophthalmology • Controlling pneumatically operated surgical tools
for cataract surgery Dialysis for kidney diseases • Regulating pressure for controlling the flow of liquids Medical mattresses and compression therapy • Anti-decubitus mattresses against bed sores • Devices for lymphatic drainage and compression
applications
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Piezo technology in industrial applications

Compact and energy-saving: tests to simulate cleaning teeth To simulate people’s behaviour as realistically as possible, 24 proportional pressure regulators VEAB from Festo control the contact pressure here in a constant and gradual process. In comparison with other proportional solutions, they are very reasonably priced, extremely compact and ultra-quiet.

The one-cable solution with standard connectors also makes the proportional valves extremely easy to install on a mounting plate. The valves VEAB can be placed close to the application or in a small control cabinet, which saves a significant amount of space. Thanks to their low energy consumption, they generate almost no heat and can be packed extremely closely together.

Faster and more versatile: build-up welding with argon With build-up welding, the material is applied in layers. This is done with the help of a laser that applies layer after layer of metal or plastic powder and fuses them. These additively manufactured, complex components can be produced as a single, cohesive piece. The shape doesn’t matter.
The powder is transported using argon. When dosing the powder in the laser, an appropriate amount of argon is added. The VEMD is suitable for this task when it is recalibrated for use with argon. This solution is significantly more cost-effective than conventional mass flow controllers, enabling enormous cost savings per machine.

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2/2-way proportional valves with piezo technology

Flow control The 2/2-way proportional valve controls, for example, the precise supply and metering of oxygen in oxygen therapy devices during inhalation. In combination with a flow sensor and control electronics it turns into a proportional flow control valve.

Specific opening to feed in/dose gases or gas mixtures

Valve normally closed

Valve open

With a flow sensor and control electronics it becomes a proportional flow control valve This makes piezo valves infinitely adjustable and simplifies the dosing of concentrations.

No voltage No flow rate
Medium voltage Medium flow rate
High voltage High flow rate

Characteristics of the 2/2-way proportional valve A piezo valve is subject to hysteresis characteristics just like proportional solenoid valves. When combined with a flow sensor and control electronics, a linear characteristic can be achieved.

Flow rate [lpm]

Control voltage [V] Flow in relation to the control voltage (sample curve)
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Proportional valve VEMR Valve function Connection type Ambient temperature
Nominal width [mm] Pressure range [bar] Flow rate [l/min] Media

2/2-way valve (normally closed) Flange 5 ... 40 °C (41 ... 104 °F); 0 ... 60 °C (32 ... 140 °F) 0.7; 1.2; 1.3; 1.4 0 ... 1.7; 0 ... 2; 0 ... 3.8; 0 ... 6 0 ... 30 Air, inert gases, oxygen

Proportional valve VEAE Valve function Connection type Ambient temperature Nominal width [mm] Pressure range [bar] Flow rate [l/min]
Media

2/2-way valve (normally closed) Flange −10 ... +85 °C (14 ... 185 °F) 1.2; 1.5; 1.7 0 … 3; 0 … 6 0 … 20 lpm at 0,5 bar 0 … 55 lpm at 5 bar 0 … 80 lpm at 6 bar Air, inert gases, oxygen

Pressure range adaptation Change of the flow rate Adjustment of the operating temperature Appropriate electronics

We modify our products specially foryou in line with your needs. Do you have a specific requirement but cannot find the right product in our product range? You will receive individual product versions from us that precisely meet your needs. Just contact us.
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3/3-way proportional valves with piezo technology

Pressure regulation For controlling pressure, for example in lymph drainage devices. The special bender actuator works on the basis of differential movements and thus provides almost complete compensation for temperature-related errors. In combination with a pressure sensor and control electronics the 3/3-way proportional valve turns into a proportional pressure regulating valve.

Gap-type bending actuator: three functions in one valve

Supply air Pressure is increased

Exhaust air Pressure is reduced

Valve normally closed No air flow Pressure is maintained

With pressure sensor and control electronics it becomes a proportional pressure regulating valve Controlled pressure increase and decrease with soft-start function.

Maintaining pressure

Blocking

Changing pressure

Blocking

Exhausting Pressurising

Characteristics of the 3/3-way proportional valve Flow in relation to the control voltage (sample curve).

Exhausting Pressurising

Flow rate connection side [lpm] Flow rate exhaust side [lpm]

0

Control voltage [V]

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