0
Design Innovation Paper

Design of High Speed Rotary Valves for Pneumatic Applications

[+] Author and Article Information
Travis L. Brown

Aerospace and Mechanical Engineering,
University of Notre Dame,
Notre Dame, Indiana 46556
e-mail: tbrown14@nd.edu

Prasad Atluri

GM Global Research
Warren, MI 48090
e-mail: vprasad.atluri@gm.com

James P. Schmiedeler

Aerospace and Mechanical Engineering,
University of Notre Dame,
Notre Dame, IN 46556
e-mail: schmiedeler.4@nd.edu

1Corresponding author.

Contributed by the Design Innovation and Devices of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received April 16, 2012; final manuscript received August 12, 2013; published online October 17, 2013. Assoc. Editor: Craig Lusk.

J. Mech. Des 136(1), 015001 (Oct 17, 2013) (7 pages) Paper No: MD-12-1204; doi: 10.1115/1.4025487 History: Received April 16, 2012; Revised August 12, 2013

Valves based on rotating geometry have long been sought by designers for their simplicity, compactness, and desirable dynamic properties. Unfortunately, they generally involve tight sealing surfaces with significant relative motion, making them particularly prone to problems of wear, leakage, and seizure. These inherent weaknesses are easily overcome in applications involving low pressures or low actuation speeds but become more significant in applications with high pressures and/or high speeds. In this paper, a new high speed, high pressure rotary valve design for an experimental reciprocating compressor-expander is presented. A physical prototype is created, and leakage and valving experiments are performed. Sealing performance is verified and shown to be on the order of piston ring leakage, making it suitable for compressor use. Although not intended for combustion applications, it is possible that a modified version of this design could function in that capacity. As shown, this design is useful in pneumatic applications in which temperatures are lower and oil leakage is tolerable.

FIGURES IN THIS ARTICLE
<>
Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Basic valve system geometry (cross-section view). (1) Valve Shaft, (2) Valve Bearings, (3) Valve Seals, (4) Rotary Shaft Seals. The valve seals and valve springs (not shown) move within a cylindrical hole which guides the valve seals into contact with the valve shaft. O-rings are used to seal the valve seals to the head.

Grahic Jump Location
Fig. 2

Simplified cross-sectional view of valve head showing various components of the valve design.

Grahic Jump Location
Fig. 3

Exploded view of the final valve head design. Small fasteners and valve springs are omitted for clarity.

Grahic Jump Location
Fig. 4

Illustration of an intersection line on a hypothetical example geometry. Intersection lines determine the rate of change of valve area.

Grahic Jump Location
Fig. 5

Overlap profile for various valve geometries. The size of all ports was adjusted to result in the same maximum open area and same valve timing. The variable D represents the center-to-center distance at which the valves begin opening. Wide rectangular cross sections lead to the fastest open times but require larger valve seals.

Grahic Jump Location
Fig. 6

External geometry of the compressor expander. (1) Valve Shaft Timing Pulley (2) Valve Timing Adjustment Bolts (3) Valve Belt Tensioner (4) Tensioner Arm (5) Backshaft (6) Crankshaft Timing Pulley. Timing belt is not shown.

Grahic Jump Location
Fig. 7

Experimental setup (1) Rotary Encoder (2) Compressor (3) DC Motor (4) Air Tank (5) Temperature and Pressure Sensors (6) Rotary Valve Head

Grahic Jump Location
Fig. 8

Pressure decay and calculated leakage rate for 1 h starting at approximately 120 psi gauge (927 kPa absolute). The time derivative of pressure, necessary for finding the leakage rate, is calculated by fitting an exponential curve to the pressure data and differentiating this curve.

Grahic Jump Location
Fig. 9

Leak rates for 4 different speeds of operation. Solid lines represent actual experimental data, dotted lines are extrapolations.

Grahic Jump Location
Fig. 10

Results of a compressor functionality test. With the valve shaft in place, the compressor was able to charge the tank up to 900 kPa absolute pressure. This shows that the valve system both opens and closes properly under operating conditions.

Grahic Jump Location
Fig. 11

The prototype valve shaft next to two bronze valve seals. Some discoloration on the valve shaft is visible after tens of operating hours. These marks are bronze colored and appear to be metal transfer from the valve seals. No wear of the valve shaft is detectable.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In