By generating a vacuum during walking within the socket, the DVS maintains a level of elevation in both swing and stance phase. This sets it apart from passive systems, such as valves, where vacuum is only generated in the swing phase. Developed for easy fabrication, fittings are simplified for both the patient and prosthetist.
Other DVS advantages:
- Works well with standard socket designs to simplify fittings
- A low-profile, lightweight design
- Does not require external tubing that can get tangled in clothing
After a patient steps into the socket, magnetic coupling occurs between the liner and the piston. During swing phase, the piston moves in the proximal direction due to the centrifugal force. The difference in pressure between the cylinder chamber and the inside of the socket results in a flow of air from the socket to the cylinder chamber.
A one-way valve in the piston ensures that the air does not flow back into the socket. When the user places his or her weight on the prosthesis in stance phase, the air is ejected from the cylinder chamber. Another one-way valve in the body of the cylinder prevents the air from flowing back. A vacuum develops after just a few steps.
The DVS generates a vacuum level which adjusts itself dynamically to the increase in movement. With faster walking and higher forces the vacuum will increase accordingly.
