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Our People - Experienced Valve Engineers

Onyx Valve Company
835 Industrial Hwy
Cinnaminson, NJ 08077
Ph: 856-829-2888
Fax: 856-829-3080

Our People. Our Strength.

The Onyx Valve Company is only as strong as its people, and our people have the most experience in the industry.  Our people are experienced and helpful and work day in and day out to please our customers and manufacture best flow control products the industry has to offer.  We encourage you to read through our profiles to get to know us.



david gardellin

David Gardellin, P.E., CEO

Co-founder and President of Onyx Valve Company, David is your primary technical resource for the measurement and control of slurries and other hard-to-handle fluids.  He has been involved in valve engineering since starting as Chief Engineer at RKL Controls/Robbins & Myers in 1975.  He holds a BSME from Drexel University and is a registered Professional Engineer in Maryland and New Jersey.  He holds several patents related to pressure measurement and control, and is the author of numerous technical articles including chapters in the ISA Instrument Engineer’s Handbook and the Encyclopedia of Chemical Processing and Design.

Contact David at david@onyxvalve.com

Chuck Witherow, Vice President of Sales

Extensive background in Supervison, Project Management, Sales and Trade Shows.
Formal training, schooling and experience in Electronic/Electro/Mechanical as well as customer service support.
Chuck manages and supports Onyx Valve Reps and Customers in many countries around the world.
His professional approach, communication and customer service skills and technical knowledge is a great asset to our company and customers.

Contact Chuck at cwitherow@onyxvalve.com

Monica Handley

Monica Handley, Sales Engineer

Technical Sales: A graduate from Rutgers University School of Engineering, Monica is happy to step into her role as Sales Engineer at Onyx Valve. While in school Monica took advantage of every available opportunity, trying her hand at everything from HVAC, commercial architecture, costume design, fundraising, songwriting, customer service, cutting vegetables into perfect cubes, and sustainable energy design. Monica can provide you with pricing and technical support to apply pinch valves, isolator rings, or duckbill check valves for almost any conceivable application.

Contact Monica at mhandley@onyxvalve.com

Elizabeth A. Salmi, Sales Engineer

Technical Sales: Elizabeth Salmi is thrilled to join Onyx Valve Co. as their newest Sales Engineer. A Bachelor of Science degree in Applied Sciences Engineering with a focus in Environmental Engineering, combined with her experience in process control make her the ideal contact person to help you select the right valves and pressure measuring instruments for all of your environmental applications like storm water and waste water. Her goals in life are to sell all the valves and meet Dolly Parton.

Contact Elizabeth at esalmi@onyxvalve.com

Meredith Foster

Meredith Foster, Expediting and Traffic

Contact Meredith to check order status and for help arranging shipments to or from Onyx Valve Co including ground freight and expedited freight options.

Contact Meredith at mfoster@onyxvalve.com


Taylor Mahon

Taylor Mahon, Purchasing Agent

Taylor Mahon is your key contact for Outside Purchasing at Onyx Valve Co. With years of experience in customer service and sales, Taylor is quick to purchase instrumentation and raw materials necessary to complete orders, verify their specification and schedule incoming deliveries, organize any and all documentation, and compare receipts to ensure correct and on-time delivery for final products. If you’re an Onyx supplier, Taylor can clarify any unclear items to make certain we’re getting what’s best for the customer.

Contact Taylor at tmahon@onyxvalve.com

Chris Schmidbauer, Engineer, B.S.M.E.

Chris Schmidbauer is responsible for valve design. He is also your contact person for submittal packages and any other documentation related to pinch valves and duckbill valves.

Contact Chris S. at cschmidbauer@onyxvalve.com


Robert Delfino, Draftsman/Designer

Rob is your first contact for certified pressure sensor drawing submittals and approval drawings.  He is also in charge of processing all pressure sensor orders and the design of all specialty pressure sensor projects.

Contact Rob at rdelfino@onyxvalve.com


Howard Leisner

Howard Leisner, Controller

Contact Howard for issues related to credit approval, wire transfers, customs and special payment terms and conditions.

Contact Howard at hleisner@onyxvalve.com


Katherine Foster, Accounting

Katherine is your first contact for AP, AR and credit card transactions.

Contact Katherine at accounting@onyxvalve.com



Mark Massimilla, Designer

Co-founder and Lead Designer, Mark is responsible for product design, research & development and the company’s manufacturing database.  He has been involved in valve design since he started as a Designer at RKL Controls/Robbins & Myers in 1984.

Contact Mark at massimilla@onyxvalve.com


Robert Schmied, Machine Shop Foreman

Bob is the machine shop foreman, and one of the founders of the Onyx Valve Company. His responsibilities include supervising the daily operation of the machine shop and final parts inspection. Bob was a machinist and shop foreman at RKL Controls/Robbins & Myers, and has over 30 years experience in the pinch valve industry.

Contact Rob at rschmied@onyxvalve.com


Dave Headley, Assembly Foreman and Co-founder

Dave has over 30 years’ experience building pinch valves. He has assembled, installed and repaired valves with pneumatic, electric and hydraulic actuators and positioners, and has assembled, calibrated and repaired pressure gauges, switches and transmitters.