Valve Seats
for Floating Ball Valves
A valve seat is the precision-machined ring inside a valve that the moving element — in a ball valve, the ball — presses against to form a tight, leak-free seal. ISMAT machines them from PTFE and PEEK engineering plastics in 11+ Novum grades.
Send us your seat dimensions, valve body drawing or fluid specification — our engineers respond within one working day.
Precision contact surfaces that stop the flow
Seats sit on both sides of the ball and provide the contact surfaces that stop flow when the valve closes. Materials — polymers, metals or composites — are selected for fluid, temperature, pressure and wear compatibility.
When closed, line pressure forces the ball into the downstream seat, compressing the contact area for leak-free shutoff. Seat design, surface finish, material choice and machining tolerances control load distribution, wear rate, chemical resistance, abrasion tolerance and deformation.
Floating ball valve operation
How a precision-machined engineering-plastic seat forms and holds a bubble-tight shutoff through the valve cycle.
The ball is not mechanically anchored. Two seats hold it loosely in position while the stem guides rotation. Fluid flows freely through the open bore.
A 90° rotation blocks the flow path. The ball swings across the bore and meets the downstream seat for the first time in that cycle.
Line pressure from upstream pushes the ball firmly into the downstream seat. The engineering plastic deforms slightly, fills micro-gaps and creates the tight contact zone.
The harder the fluid pushes, the tighter the seat holds. This self-energizing behaviour achieves ANSI Class VI performance consistently across thousands of cycles.
The case for PTFE and PEEK valve seats
PTFE and PEEK carry an exceptionally low coefficient of friction. The ball glides rather than drags — low operating torque, effortless actuation and wear rates far below most other seat materials.
From mild acids, solvents and water-treatment chemicals to food-grade fluids and process gases, Novum grades resist chemical attack without any external coating or lining.
The natural conformability of engineering plastics forms intimate contact with the ball surface, yielding ANSI Class VI shutoff for utility, instrumentation and process-control lines.
Virgin PTFE and PEEK grades are non-toxic, non-leaching and non-contaminating — accepted in pharmaceutical, food & beverage and water-treatment applications.
Matched to the right Novum grade for your media and temperature, you get consistent sealing across thousands of cycles. Creep and wear are engineerable and quantifiable — not variable.
With more than eight grades, you match the seat to your exact media compatibility and mechanical load rather than accepting an approximation.
Novum Grades for Valve Seats
Eleven-plus engineering-plastic grades — match the seat to your exact media, temperature and mechanical load.
| Novum Grade | Material | Key Properties | Best Suited For |
|---|---|---|---|
| NOVUM VESP 01 (CR6100) | Vespel® CR-6100 (DuPont Composite — Carbon Fibre Reinforced) | API STD 610 / ISO 13709 compliant; −46°C to 230°C; extremely low creep; compressive strength 174 MPa; near-zero water absorption 0.01% | Severe-service seats in petroleum, petrochemical and natural gas service where PTFE cold flow is a known failure mode and dimensional stability under load is non-negotiable. |
| NOVUM PKCT 01 | Victrex CT 200 (PAEK — Cryogenic Grade) | Cryogenic to −196°C; tensile 140 MPa at −196°C; compressive 250 MPa at −196°C; melting point 343°C | Cryogenic seats for LNG, liquid nitrogen and oxygen, and ultra-low-temperature valve assemblies down to −196°C. |
| NOVUM PCT 01 | NEOFLON PCTFE M-300H (Daikin) | Highest gas barrier of all fluororesins; near-zero permeation; Shore D 80; elongation 189%; melting point 212°C | Gas isolation, instrument and gas metering valves where permeation through the seat body is a critical failure concern. |
| NOVUM PCT 01 | NEOFLON PCTFE M-400H (High Molecular Weight — Daikin) | Higher MW than M-300H; superior stress-crack resistance; near-zero permeation; tensile 47.6 MPa; compression-moulding optimised | Thick-section and large-bore seats requiring heavy cross-sections without cracking; sustained-load gas isolation service. |
| NOVUM PA 01 | DEVLON V-API (Polyamide Composite — James Walker) | API valve service rated; compressive 140 MPa; Shore D 82/85; service to 125°C; low SG 1.14 | API-rated floating ball valve seats for oil & gas; a direct match for OEMs building to API 6D / 608 / 6A (water absorption 3% at saturation). |
| Novum P 01 | Virgin PTFE | Ultra-low friction; full chemical inertness; FDA-compliant; excellent conformability | Water, mild acids, alkalis, general process fluids; food and pharmaceutical applications. |
| Novum M 03 | Modified PTFE (TFM) | Better creep resistance vs virgin; improved weld-seam integrity; lower deformation under load | Utility valves and low-to-medium cycle applications where dimensional stability over time matters. |
| Novum GF 01 | 15% Glass-Filled PTFE | Enhanced wear resistance; improved compressive strength; retains PTFE chemical resistance | Higher cycle-count applications and valves handling mild abrasive carry-over. |
| Novum GF 02 | 25% Glass-Filled PTFE | Higher stiffness than GF 01; superior dimensional stability; reduced cold flow under sustained load | Industrial process lines with sustained differential pressure across the seated valve. |
| Novum MOF 01 | Glass and MoS₂ Filled PTFE | Excellent wear resistance; self-lubricating under dry conditions; dimensional stability under load | Dry-running risk conditions and high cycle-frequency industrial valve service. |
| Novum CF 02 | Carbon-Filled PTFE | High compressive strength; static dissipative; low permeation; API 6A suitable | Chemical and solvent lines where electrical neutrality of the seat material is specified. |
| Novum PK 01 | Virgin PEEK | Outstanding mechanical strength; excellent chemical resistance; very low creep; dimensional precision | Applications demanding tighter tolerances or higher mechanical load resistance in demanding service. |
| Novum PKC Series | PEEK Composite | Tailored strength and wear; stable under load; high-precision machining | High-performance OEM applications and custom seat geometries needing tight batch-to-batch repeatability. |
Grade data is indicative; final selection depends on full operating conditions. Contact ISMAT for application-specific recommendations.
Why specifiers choose ISMAT seats
Every seat is machined to tolerances that ensure full, even contact with the ball. CNC control eliminates the inconsistent geometry that causes early seat leakage.
The natural low-friction surface lets the ball rotate without dragging — lower operating torque and no lubricant contamination risk in sensitive fluids.
Properly specified grades maintain their sealing geometry through high cycle counts, holding shutoff long into service life without re-seating.
The Novum range means you specify a seat matched to your exact media compatibility and mechanical load — not a compromise.
We machine custom seat geometries, non-catalogue bore sizes and special face angles to OEM valve body drawings, with full CNC repeatability across batches.
Every shipment is traceable to raw-material batch and manufacturing date through our ISO 9001:2015 system. Material certificates and inspection reports on request.
40+ years of engineering-thermoplastics expertise
Our team can look at an application, a media specification or a worn-out seat and tell you exactly which Novum grade fits, why it fits and what to expect in service — knowledge that comes from decades of solving real application problems, not catalogue ordering.
In-house CNC machining means a single source for both material expertise and the finished component. Safety stock in raw compounds and standard profiles keeps lead times short, and in-house tooling makes prototyping and first-article inspection fast.
Industries we serve
Engineering-plastic valve seats specified across the most demanding fluid-control applications.
Frequently asked questions
Virgin PTFE is the most widely used material for soft-seat floating ball valves across general industrial, water treatment, food and chemical applications. For better dimensional stability or higher mechanical loads, Modified PTFE (Novum M 03) or glass-filled grades are the typical next step.
Both offer excellent chemical resistance and low friction, but Modified PTFE (TFM) has lower creep — it deforms less under sustained load, giving better shape retention under sustained differential pressure or frequent cycling.
Yes. Our CNC machining covers both standard catalogue profiles and fully custom geometries from drawings, CAD files or physical samples, with full dimensional inspection documentation and batch-to-batch repeatability.
For most floating ball valve applications PTFE grades are the right choice for chemical resistance and conformability. PEEK is better where you need tighter tolerances, higher mechanical load resistance, or where PTFE cold-flow under sustained stress would be a concern.
Yes. We supply precision-machined engineering plastic valve seats directly to valve manufacturers and OEMs, working to OEM drawings, qualifying to incoming inspection requirements and supplying in production volumes with full lot traceability.