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Radial Chevron Baffle

IP.com Disclosure Number: IPCOM000080663D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Lester, WC: AUTHOR

Abstract

A conventional cryo-cooled baffle for a nominal six-inch diffusion pump is about nine-inches high, and is mounted between the pump and high-vacuum isolation valve. The actual speed of the diffusion pump is limited by the conductance of the cross-sectional area of the baffle flange ports, the baffle chevrons, or plates, and the distance of the pump inlet flange from the vacuum chamber.

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Radial Chevron Baffle

A conventional cryo-cooled baffle for a nominal six-inch diffusion pump is about nine-inches high, and is mounted between the pump and high-vacuum isolation valve. The actual speed of the diffusion pump is limited by the conductance of the cross-sectional area of the baffle flange ports, the baffle chevrons, or plates, and the distance of the pump inlet flange from the vacuum chamber.

A radial cheveron baffle has been designed, to provide significantly increased conductance and resultant pumping speed between the diffusion pump and the vacuum chamber. The radial baffle 1 is cylindrical in shape and projects into the vacuum chamber or manifold. The vertical chevron baffles 2 are located on the periphery of the cylinder, providing increased conductance area while maintaining trapping efficiency.

A liquid nitrogen reservoir 3 is located in the top of the cylindrical baffle assembly. The inverted conical lower surface 4 provides a maximized cryogenic oil vapor trapping area and is positioned to enhance the trapping probability. The domed top surface 5 of the reservoir 3 provides a cryo-pumping surface for condensable system residual gases (primarily water vapor). The heat sink rings 6 and 7 at the upper and lower ends of the vertical chevrons 2 insure uniform cooling of the chevrons. A thin wall stainless steel oil return sleeve 8 connects the lower heat sink ring 7 to the baffle assembly mounting plate 9 with minimal thermal conductance.

The li...