Mr. Chester Siver

In 1962, Mr. Chester Siver completed designs for a revolutionary line of high-pressure, forged steel valves. Hamilton Standard (now Hamilton Sunstrand), a division of United Technologies Corporation, was asked to use their then-new Electron Beam Welding technology for the joining of parts into valves for subassemblies. Hamilton Standard became intrigued with the valve as an ideal application of the Electron Beam Welding technique and negotiated a contract for the rights to manufacture and sell the valve. Mr. Siver served as manager of the valve project.

The first CLAMPSEAL® valves were introduced to the market by Hamilton Standard in 1964. However, in the mid-1960’s, growing demand for the firm’s popular aerospace products forced Hamilton Standard to make the decision to abandon its industrial products projects. The rights to the CLAMPSEAL valve reverted back to Mr. Siver. Since CLAMPSEAL® valves were born in Connecticut, Mr. Siver founded “Conval” in 1967. Today the valves are still manufactured in Connecticut, a state with a longstanding reputation for technological innovation and manufacturing excellence.

From the early years, the company has steadily expanded its product line to where it now includes: Y, Angle, and T-pattern Globe valves and Gate valves in 900 – 4500 lbs. pressure classes and 1/2″ – 4″ sizes; Whisperjets; Multiple Orifice Blowdown valves; Cryogenic and Bellows Seal valves. Today Conval is the premier manufacturer of high quality, high temperature, and high pressure forged steel valves in the world. Conval has expanded sales in Southeast Asia and developing third world countries.


Conval has become a leader in providing valves for the world’s most demanding applications. We have a global team of experts to meet your most challenging needs. We invite you to contact us today. We offer high-pressure, high-temperature ball, bellows, check, gate, globe, throttling, and urea service valves.

The CLAMPSEAL® valve represents the proverbial better mouse trap. Ingeniously simple, the basic valve is comprised of only nine components. The valves are lightweight and at the same time incredibly tough and durable. Perhaps most significant of many advantages, the CLAMPSEAL® valve is much easier to renew than any other globe valve on the market. The days of use it up and throw it out have been replaced with a desire for quality, renewability, and longevity. Low acquisition cost is not as important as low life-cycle cost. Conval has benefited from this change in perspective.

Conval celebrated its 40th anniversary in 2007 with the launch of the new Camseal® Ball Valve. Sophisticated state of the art techniques are used for applying hard coatings, grinding and lapping the ball and seat of the Camseal®. The extremely high density of the coating and the precise lapping techniques produce a ball-to-seat seal that is bubble tight, and will remain bubble tight during and after installation. The Camseal® ball valve has been subjected to rigorous computer-aided analysis, laboratory testing and field testing during its development. State of the art 3-D computer modeling was used to optimize the details of the valve followed by extensive laboratory testing to verify the results. The valve has consistently passed a very rigorous program of tests.

The future is promising. Conval marked its 50th anniversary with the purchase of a 70,000 sq. ft. facility in Enfield CT. This more than doubled the manufacturing and office space of our former three building campus. We continue to develop new products to satisfy the challenging demands from industry. Inspired leadership and the innovation provided by a new generation of engineers assures our continued success.

Celebrating 50+ years of excellence!

Thank you for your business.