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Houston, TX, United States of America

Keystone International

USPTO Granted Patents = 49

Trademarks = 1

Forward Citations = 725

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27 inventors (with patents filed for the assignee):

William B Scobie (16 out of 20 patents)

Henry R Killian (5 out of 7 patents)

Edward G Holtgraver (4 out of 9 patents)

4. Michael L Wagberg (4 out of 4 patents)

5. Walter W Powell (3 out of 16 patents)

6. Paul A Yohner (3 out of 5 patents)

7. Larry A Sample (3 out of 5 patents)

8. Joe L Aldrich (3 out of 3 patents)

9. Petrus J Schils (3 out of 3 patents)

10. Cleo M Bickford (3 out of 4 patents)

11. Douglas G Calvin (2 out of 15 patents)

12. Walter T Roush (2 out of 4 patents)

13. Daniel P Kusmer (2 out of 2 patents)

14. William Stahley (1 out of 1 patent)

15. Richard Bryan Lee (1 out of 5 patents)

Core Competencies:

High-Speed Image Transfer

Safety Relief System

Butterfly Valve

Valve Assembly

Corrosion-Resistant Overlay

Check Valve

Manual Control

Material Level Detector

Rotatable Valves

Block and Bleed System

Actuator

Die-Casting

49 patents: Sort by Forward Citations

1. 6771821 - High-speed image transfer system (2004-08-03),

2. 5090658 - Bellows sealed rotary valve and seal assembly (1992-02-25),

3. 5042151 - Method for removing and inserting valve seats (1991-08-27),

4. 4982483 - Valve seat tool for removing and inserting value seats (1991-01-08),

5. 4964432 - Method and means for mounting valve member on valve stem (1990-10-23),

6. 4898201 - Portabl tool for cleaning valve bores and associated inlet passage (1990-02-06),

7. 4870989 - High temperature safety relief system (1989-10-03),

8. 4865074 - High temperature safety relief system (1989-09-12),

9. 4862910 - Check valve with disc centering device (1989-09-05),

10. 4848397 - High temperature safety relief system (1989-07-18),

11. 4846441 - Methods and apparatus for adjusting a valve closure member (1989-07-11),

12. 4846225 - Transmission assembly for use with double block and bleed system (1989-07-11),

13. 4846212 - Bleed valve assembly for double block and bleed system (1989-07-11),

14. 4828221 - Valve assembly (1989-05-09),

15. 4817213 - Method for forming a torus and a piston made therefrom for use in a (1989-04-04),

Keystone International, based in Houston, TX, specializes in advanced valve technologies and high-speed image transfer solutions. The company focuses on the design and manufacture of a diverse range of valve products, including bellows sealed rotary valves, check valves, and fireproof valve assemblies, catering to various industrial applications. With a commitment to innovation, Keystone International aims to enhance safety and efficiency in fluid control systems, leveraging its expertise in high-temperature safety relief and specialized valve construction.

Profile summary based on public USPTO records.

Company Badge

USPTO Data Jan 1 1976 - Sep 29 2026

49 Patents

#115 in Houston, TX

#386 in Texas

#7,133 in US

#14,256 in the World

Houston, TX, United States of America

Keystone International

Forward Citations = 725

27 inventors:

William B Scobie (16 out of 20 patents)

Henry R Killian (5 out of 7 patents)

Edward G Holtgraver (4 out of 9 patents)

4. Michael L Wagberg (4 out of 4 patents)

5. Walter W Powell (3 out of 16 patents)

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