Lapping Solutions For Cryogenic Pumps, Seals & Valves
Our diamond lapping process for cryogenic valves, seals, and pump assemblies delivers surface finishes as fine as Ra 0.025 µm alongside flatness tolerances reaching 0.001 mm. We commence every project with component assessment to establish an appropriate lapping approach according to material composition, component configuration, and operational demands. Our processes employ diamond compounds spanning 0.1 to 25 microns, We always aim for a single stage process when possible.
We utilise our 50 years’ experience of lapping processes to obtain surface finishes down to Ra 0.005 µm and flatness of less than 0.5µ.
Our capabilities extend to spherical and annular groove lapping for intricate geometries. Automated match-lapping technology produces mated spherical surfaces for cryogenic ball valves. Special bespoke Kemet composite laps enable lapping of shaft mounted sealing surfaces whilst preserving the necessary profile characteristics and surface quality.
We supply portable lapping kits suitable for field refurbishment of valves and mechanical seals, minimising operational downtime by removing the requirement for complete system dismantling. These kits, accompanied by training programmes, allow maintenance personnel to deliver quality results on-site. Our technical laboratory offers component assessment and process development for specialised applications.
Specialist Material Processing
Our experience encompasses materials used in cryogenic applications, with processes developed for each material category to deliver the required surface finish and flatness.
Stainless Steel (300 Series)
Popular grades including 304, 316, and 347 feature in cryogenic valve construction. Our lapping techniques deliver down to mirror-like finishes.
Tungsten Carbide
A common choice for mechanical seal faces, tungsten carbide's hardness requires diamond lapping for cryogenic-grade finishes.
Silicon Carbide
Both reaction-bonded and sintered variants are common materials for Kemet. Specialised diamond formulations combined with controlled pressure techniques produce quality sealing surfaces despite the material's hardness and fragility.
Stellite and Hard-Faced Components
Valve seats featuring Stellite 6 or 12 hard-facing require careful lapping to remove the coarse overlay finish whilst maintaining seal geometry. Our processes generate precision sealing surfaces without edge degradation or dimensional changes.
Advanced Ceramics
Alumina, zirconia, and silicon nitride seal faces undergo lapping using refined diamond slurries and purpose-designed plates to achieve high flatness and surface characteristics. Controlled-pressure help prevent microcracking whilst ensuring consistent outcomes.
PTFE and Composite Materials
Soft materials including PTFE and filled PTFE variants benefit from gentle lapping to enhance surface consistency and sealing characteristics. Our adapted techniques improve seal performance without compromising the polymer structure.
Cryogenic Components We Regularly Process
Ball Valve Seats and Seals
LNG ball valves require spherical seats to maintain sealing performance throughout temperature fluctuations. Smooth ball rotation must be coupled with reliable sealing in the closed position. Our range of Spherical Lapping Machines can generate matched ball and seat assemblies. The process establishes a spherical radius on both components for contact across the sealing area.
Gate Valve Sealing Surfaces
Gate valve seats operating in liquid oxygen, nitrogen, and argon environments require both flatness precision and superior surface finish. We process valve discs and seats for metal-to-metal sealing at cryogenic temperatures. Gate valves present challenges as sealing faces must maintain flatness across their complete diameter whilst in the open and closed position. It’s typical that these gate valves may not be used for long periods of time, but need to work effectively when needed. Our flat lapping methodology preserves flatness within 0.001mm whilst delivering Ra 0.05µm surface finish.
Mechanical Seal Faces
Cryogenic pump mechanical seals—whether carbon-versus-tungsten carbide or silicon carbide-versus-silicon carbide configurations—require high surface quality. We process both rotating and stationary seal faces to industry specifications.
Relief Valve Seats
Safety relief valves safeguarding cryogenic vessels and pipework must reseat following discharge events. We process both valve disc and seat components to help ensure reliable resealing at cryogenic temperatures. The precision sealing surfaces we develop support the proper function of these safety mechanisms. Our portfolio includes relief valve components for LNG installations, liquid hydrogen facilities, and liquid oxygen production plants.
Why Partner with Kemet for Cryogenic Applications?
With more than 85 years of precision lapping experience, we've handled components for a wide range of applications. Our clientele spans global energy corporations, industrial gas manufacturers, aerospace companies, research facilities, and valve producers. Partnering with Kemet means accessing specialist knowledge and established processes. Our engineers understand the challenges of cryogenic sealing and can suggest appropriate strategies for your particular components.
Through our worldwide distributor network and portable equipment available for hire or purchase, we support operations in many locations. Equipment and consumables reach customers globally, with technical assistance provided. For projects requiring on-site support, we coordinate training and commissioning at your premises. Whether you require equipment, consumables, training, or refurbishment services, Kemet provides lapping solutions for cryogenic applications.