Stainless Steel Lug Butterfly Valve Handle Operated CF8 CF8M Resilient Seated

The stainless steel lug butterfly valve with handle operation is a centreline resilient-seated quarter-turn valve engineered for pipelines that require corrosion-resistant wetted parts, compact lug-type installation and dependable manual shut-off. Manufactured by Trekre Valve, this handle operated stainless steel lug butterfly valve uses CF8 or CF8M body and disc castings with moulded PTFE, EPDM or NBR seat liners, dry-shaft stem design and lug ears for installation between companion flanges. The lug-hole pattern and fastener arrangement must follow the approved valve drawing; any end-of-line or single-flange use requires a documented rating for the exact size and configuration. A lightweight aluminium alloy handle provides 90-degree rotation for fast isolation on water, sewage, air, light oil and general industrial utility headers.

Centreline concentric geometry keeps the disc rotation axis on the body centreline, which simplifies manufacturing and reduces parts count. When fully open, the butterfly disc remains in the flow path; actual pressure loss depends on valve size, disc profile, opening angle, flow rate and the Cv or Kv of the selected valve. Compare flow resistance with gate, globe or other valve types using project-specific flow data rather than assuming a universal lower pressure loss. Resilient seat materials compress against the disc edge at closure, while PTFE, EPDM or NBR seat selection must remain within the verified pressure, temperature and media limits of the selected configuration.

Stainless steel lug butterfly valve construction

Connection type: lug type; lug drilling and fastener arrangement shall match the approved valve drawing and selected companion flange standard. End-of-line or single-flange service requires a documented rating for the exact valve size and configuration.

Structure: centreline concentric butterfly valve, resilient soft seat

Size range: 2″ to 24″ (DN50 to DN600)

Pressure rating: ANSI Class 150, JIS 10K/20K, EN PN10/PN16 (size and standard dependent)

Body material: CF8 (304) or CF8M (316) stainless steel

Disc material: CF8, CF8M, CF3M or duplex 2507 on request

Stem material: CF8/CF8M or SS416 with blow-out proof lower bearing

Seat material: PTFE, EPDM, NBR or VITON moulded resilient liner

Operation: manual handle lever (aluminium alloy); worm gear or actuator upgrade available

Top flange: ISO 5211 pad for field conversion to gear box, pneumatic or electric actuator

Temperature range: -10°C to 180°C depending on seat compound selection

Standards: API 609 Category A, EN 593, MSS SP-67, ISO 5211 mounting interface

Material options and corrosion resistance

CF8 stainless steel (ASTM A351 CF8 / 1.4308) suits food-grade water, HVAC chilled loops, compressed air and neutral chemical services where general corrosion resistance is required without the molybdenum premium of 316 grades. CF8M (316 equivalent) adds improved pitting and crevice corrosion resistance on chloride-bearing water, coastal HVAC plants, pharmaceutical utilities and light chemical blending lines. For more aggressive brine, bleaching liquors or duplex-process streams, CF3M or duplex 2507 disc options can be paired with PTFE or RPTFE seats after engineering review of temperature, pressure and cycle frequency.

Seat selection follows the medium and operating temperature. EPDM liners handle municipal water, wastewater effluent and hot water up to approximately 120°C with good ozone and weathering stability outdoors. NBR seats suit oil, fuel and hydrocarbon condensate within moderate temperature limits. PTFE seats extend chemical resistance on acids, caustics and solvents while maintaining low friction for repeated manual cycling. Trekre Valve documents body and seat material certificates so EPC contractors can reconcile heat numbers with project material specifications during receiving inspection.

Handle operation and ISO 5211 actuator readiness

The aluminium alloy handle attaches directly to the upper stem, providing indexed 0° and 90° positions and low operator effort on nominal bores up to approximately 8″ on water service. Handle length and grip design follow ergonomic requirements for plant walk-down isolation, sample point shut-off and maintenance bypass duties where automated actuation is not justified. For larger diameters or higher differential pressure, the same valve body accepts a worm gear reducer bolted to the ISO 5211 top flange, multiplying input torque while retaining self-locking closure on vertical or inclined installations.

ISO 5211 dimensions on the actuator mounting pad allow direct installation of pneumatic quarter-turn actuators or electric actuators with standardized adapters, converting the manual stainless lug butterfly valve into an automated isolation or modulating node without replacing the in-line valve. This upgrade path reduces spare-valve inventory on multi-unit projects: procurement can standardize on one body design and defer actuator selection until control philosophy is finalized. Trekre Valve confirms stem height, flange thickness and bolt circle for the selected operator torque during technical approval submittals.

Lug type installation advantages

Lug-type bodies use lugs around the valve body for the specified flange-bolting arrangement. Depending on the actual design, lug holes may be tapped or through-hole configurations; these arrangements must not be treated as interchangeable without the approved drawing. If one piping section is to be removed while the valve remains connected on the opposite side, use only a valve size and configuration with a documented single-flange or dead-end rating and follow the approved isolation procedure.

Compared with double-flanged bodies, lug valves reduce overall length and weight while still providing stable location between ASME B16.5, EN 1092-1 or JIS flange pairs. Gasket selection follows flange rating and media: EPDM or NBR sheet for water, PTFE envelope for chemical duty, or spiral-wound gaskets on steam condensate when metal components are upgraded. Install the valve with disc slightly open to protect seat edges during bolt tightening, then cycle fully under line pressure to verify smooth rotation and correct handle orientation relative to flow direction arrows cast on the body.

Sealing performance and flow characteristics

Resilient seated centreline butterfly valves achieve low-leakage shut-off suitable for environmental and utility isolation when tested per API 598 or EN 12266-1 seat closure criteria at 1.1 times rated pressure. The disc edge contacts the moulded seat uniformly around the circumference; proper flange alignment and even bolt torque prevent seat distortion that could cause weeping at test pressure. In the partially open position, the disc introduces a predictable pressure drop that can be used for coarse flow balancing on bypass lines, though precise control applications should be evaluated against project control-valve specifications.

When fully open, the butterfly disc remains in the flow stream. Pressure loss should be evaluated from the Cv or Kv and operating flow conditions of the selected valve and compared with alternative valve types on the same project basis rather than by a blanket lower-loss claim. Quarter-turn operation and compact installation can still make stainless steel lug butterfly valves useful where space, weight and corrosion resistance are important selection factors.

Typical applications and industries

Water treatment and desalination plants specify handle operated stainless lug butterfly valves on raw water intake, filter backwash, clear well isolation and chemical dosing headers where 304 or 316 bodies resist chlorinated water and intermittent hypochlorite exposure. HVAC and building services use CF8M lug valves on chilled water, condenser water and steam condensate return with EPDM or PTFE seats matched to temperature and glycol content.

Food, beverage and pharmaceutical facilities deploy stainless lug butterfly valves on process water, CIP solutions and utility air because smooth internal bore surfaces and removable disc-seat assemblies support sanitation protocols. Light chemical and petrochemical tank farms employ PTFE-seated CF8M valves on solvent transfer, loading arm isolation and tank outlet lines where the supplied locking arrangement and the project’s isolation, depressurization, lock-out and confined-space entry procedures must be confirmed; manual handle operation alone does not establish safe isolation for vessel entry. Shipbuilding and offshore modules also use lug-pattern stainless butterfly valves on ballast, fire main and cooling water systems where corrosion resistance and compact weight are design drivers.

Product parameters summary

Model designation: stainless steel lug butterfly valve, handle operated

Nominal diameter: DN50–DN600 (2″–24″)

Pressure class: Class 150; JIS 10K/20K; PN10/PN16

Body: CF8 (304), CF8M (316), optional CF3M

Disc: CF8, CF8M, CF3M, duplex 2507 optional

Stem: CF8/CF8M or SS416, two-piece blow-out proof

Seat: PTFE, EPDM, NBR, VITON

Operator: aluminium handle; worm gear or actuator optional

Flange standard: ASME B16.5, EN 1092-1, JIS B2220 (project specified)

Design standard: API 609 Category A, EN 593, MSS SP-67

Testing: API 598 / EN 12266-1 shell and seat closure

Installation, maintenance and commissioning

Verify flange facing, bolt length and gasket type against the valve rating plate before lifting the stainless lug butterfly valve into the line. Support heavy pipe spans independently so dead weight does not load the valve body beyond manufacturer limits. After installation, exercise the handle through full open and closed positions under static line pressure, then under operating pressure, checking stem packing for leakage and confirming the disc clears the bore without rubbing.

Periodic maintenance includes inspection of seat condition, stem packing adjustment and handle locking hardware if supplied. On PTFE seats in chemical service, monitor for compression set after high-cycle duty and plan seat replacement per site maintenance intervals. Trekre Valve supplies spare seat kits, stem seals and handle assemblies matched to serial numbers recorded on factory test certificates.

Selection and ordering information

When requesting a stainless steel lug butterfly valve with handle operation, provide medium name and concentration, design temperature and pressure, nominal size, flange standard and facing, body grade (304 or 316), seat material preference, leakage class, flow direction if applicable, cycle frequency and any future actuator requirement. Our engineers confirm lug bolt patterns, ISO 5211 top flange size and handle versus gear torque suitability, then issue drawings, data sheets and material certificates aligned with project inspection and test plans.

Custom locking handles, chain wheels, extended stems, grounding lugs and position indication switches are available on request. Contact Trekre Valve with pipeline specifications to receive a quotation for this handle operated stainless steel lug butterfly valve from our Wuxi manufacturing facility.

Quality assurance from factory to site

Each valve undergoes dimensional inspection, assembly verification, shell hydrostatic test at 1.5 times rated pressure and seat closure test at 1.1 times rated pressure before release. Packing lists link serial numbers to test reports and material heat numbers so site inspectors can reconcile deliveries with purchase order line items. Trekre Valve maintains machining, surface treatment and final assembly under documented quality procedures, supporting repeat orders with consistent performance on global water, HVAC, food and light industrial projects.