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Ferrofluid Amplifier Valve

IP.com Disclosure Number: IPCOM000081450D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Helinski, EF: AUTHOR

Abstract

Fluid ink is supplied under pressure from an ink source through tubes 10 and 11 to an ink jet nozzle. Extension 12 of tube 10 extends into cavity 14 in the valve body 15. A flexible membrane 16 is attached to the valve body 15 over cavity 14, so as to cover the opening in extension 12. A nonmagnetic, resilient pad 17 of sufficient thickness is formed as part of membrane 16 for making contact with the end of extension 12. A constriction 13 in tube 10 has a relatively high impedance to flow of the liquid ink. Constriction 13 is selected to provide a pressure level at the opening of extension 12, so that the opening and closing of extension 12 by operation of membrane 16 and pad 17 functions to vary the pressure in tube 11 between zero and supply pressure.

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Ferrofluid Amplifier Valve

Fluid ink is supplied under pressure from an ink source through tubes 10 and 11 to an ink jet nozzle. Extension 12 of tube 10 extends into cavity 14 in the valve body 15. A flexible membrane 16 is attached to the valve body 15 over cavity 14, so as to cover the opening in extension 12. A nonmagnetic, resilient pad 17 of sufficient thickness is formed as part of membrane 16 for making contact with the end of extension 12. A constriction 13 in tube 10 has a relatively high impedance to flow of the liquid ink. Constriction 13 is selected to provide a pressure level at the opening of extension 12, so that the opening and closing of extension 12 by operation of membrane 16 and pad 17 functions to vary the pressure in tube 11 between zero and supply pressure.

A pool 23 of ferrofluid rests in the upper cavity 18 of valve body 15 and completely covers the membrane 16 and pad 17. The mass of ferrofluid in pool 23 is not great enough to hold pad 17 against the pressure of the fluid in extension 12, and does not result in a substantial increase in fluid pressure to the nozzle.

A C-shaped magnetic core 19 is partially submerged in the ferrofluid pool 23 above the membrane 16 and pad 17, with the core gap 20 located in line with the end of extension 12. A winding 21 on the core, when energized, causes membrane 16 to move downwardly so that pad 17 exerts a force on the opening of extension 12, to limit or stop ink flow into cavity 14 from extension 12 at a rate depending on the magnitude of the energizing current in coil 21. Thus, the rate of flow in tube 11 to the nozzle is varied accordingly. A bypass tube 22 from valve body 15 returns the ink flowing from cavity 14 to the ink source. The energization coil 21 can be under control of a feedback circuit, whi...