Balance Seals

Metal Bellow Mechanical Seal

All-metal bellow construction withstands high temperatures well beyond the limits of PTFE or elastomer-based designs
Spring-less, welded convolution design eliminates fretting and hang-up common in coil spring assemblies
No secondary elastomer required on the dynamic side, making it ideal for extreme thermal or thermal-cycling service
Precision-formed convolutions maintain consistent closing force across the bellow’s working life
Resistant to coking and carbon buildup in high-temperature hydrocarbon applications
Compact axial design suited for hot oil, thermal fluid, and high-temperature process pumps
Handles both high vacuum and moderate pressure conditions without face separation

PRODUCT DESCRIPTION

Where This Seal Delivers Beyond Standard Designs

A metal bellow seal is fitted by sliding the welded bellow assembly onto the shaft and locking it at the manufacturer-specified compression length, since the bellow's own metal convolutions generate the closing force rather than a coil spring. The stationary seat is set into the gland and aligned before final tightening, and because there's no dynamic elastomer in the design, temperature-driven expansion and contraction don't create the sealing risks they would in a conventional seal. This construction earns its place in hot oil circuits, thermal fluid heaters, and high-temperature process pumps where elastomers would harden or fail outright, and it holds its closing force reliably even through repeated thermal cycling. It's also a strong fit for vacuum or near-vacuum service, where spring-loaded designs can struggle to maintain consistent face contact. For complete step-by-step installation instructions and torque specifications, refer to our detailed installation guide on the blog.

TECHNICAL SPECIFICATIONS