{"id":1421,"date":"2026-10-29T01:00:00","date_gmt":"2026-10-29T01:00:00","guid":{"rendered":"https:\/\/wdlvalve.com\/?p=1421"},"modified":"2026-10-27T01:52:01","modified_gmt":"2026-10-27T01:52:01","slug":"large-diameter-trunnion-ball-valves","status":"publish","type":"post","link":"https:\/\/wdlvalve.com\/vi\/large-diameter-trunnion-ball-valves\/","title":{"rendered":"Large Diameter Trunnion Ball Valves: Buyer Guide"},"content":{"rendered":"<article class=\"wdl-seo-article\">\n<p><strong>Updated: October 27, 2026<\/strong> | Technical review by Wong WP, Sales Manager, Xiamen WDL Valve Co., Ltd.<\/p>\n<p><strong>Large diameter trunnion ball valves<\/strong> are selected for pipeline isolation when bore control, low pressure loss, reliable seat sealing and remote operation matter. At large pipeline sizes, design review must go beyond nominal size and pressure class: body deflection, ball support, seat arrangement, cavity-pressure relief, actuator torque, lifting, transportation and field welding can determine whether the valve works as specified.<\/p>\n<section>\n<h2>Why are large diameter trunnion ball valves a current buying topic?<\/h2>\n<p>As of October 2026, major pipeline projects are buying very large ball valves. The <a href=\"https:\/\/www.cpc.ru\/en\/tenders\/pages\/tdetailsetp.aspx?tenderid=3819\" rel=\"noopener\" target=\"_blank\">Caspian Pipeline Consortium tender 7700-OD<\/a>, published October 2, requests DN 1000 and DN 800 ball valves for the Tengiz\u2013Novorossiysk crude-oil pipeline upgrade. A second CPC tender, <a href=\"https:\/\/www.cpc.ru\/en\/tenders\/Pages\/tdetails.aspx?tenderid=3824\" rel=\"noopener\" target=\"_blank\">7696-OD<\/a>, published October 5, requests DN 1000 ball valves for the same pipeline in Kazakhstan. These owner notices are evidence of current project demand; they are not a substitute for each project&#8217;s technical specification.<\/p>\n<ul>\n<li><strong>10\/2026:<\/strong> CPC published DN 800 and DN 1000 crude-oil pipeline ball-valve tenders.<\/li>\n<li><strong>06\/2025:<\/strong> ISO 14313:2025 was published for pipeline valves and supplements API 6D, 25th edition.<\/li>\n<\/ul>\n<\/section>\n<figure><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/wdlvalve.com\/wp-content\/uploads\/2026\/10\/Industrial-Ball-Valve-Selection.jpg\" alt=\"large diameter trunnion ball valves for oil and gas pipelines\" width=\"257\" height=\"257\"><figcaption>Representative WDL industrial ball valve. Final size, construction and actuator are selected to the project data sheet.<\/figcaption><\/figure>\n<section>\n<h2>What changes when a trunnion ball valve becomes large?<\/h2>\n<p>A trunnion-mounted ball is supported by bearings rather than being forced against the downstream seat by line pressure. This limits seat loading and makes large sizes practical. Yet scaling a valve is not a simple geometric exercise. A heavier ball, greater body span and larger end loads can change deformation, bearing loads, stem torque and sealing contact. WDL&#8217;s <a href=\"https:\/\/wdlvalve.com\/vi\/product-category\/cac-loai-van\/van-bi\/\">industrial ball valve range<\/a> provides context for available valve families; a project-specific drawing is still required for any large trunnion design.<\/p>\n<p>The manufacturer should therefore confirm the design basis for pressure loads, piping loads and the selected support arrangement. The purchaser should also state installation orientation, buried or above-ground location, design life, operating frequency and whether the line will be pigged.<\/p>\n<\/section>\n<figure><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/wdlvalve.com\/wp-content\/uploads\/2026\/09\/DM_20260327165721_002.jpeg\" alt=\"large diameter trunnion ball valve pipeline application\" width=\"600\" height=\"450\"><figcaption>Onshore pipeline application context; the large-diameter trunnion configuration must follow the approved project drawing.<\/figcaption><\/figure>\n<section>\n<h2>Full bore or reduced bore?<\/h2>\n<div style=\"overflow-x:auto;width:100%;-webkit-overflow-scrolling:touch;\">\n<table style=\"border-collapse:collapse;min-width:760px;width:100%;\">\n<thead>\n<tr>\n<th style=\"border:1px solid #000;padding:10px;text-align:left;\">Decision factor<\/th>\n<th style=\"border:1px solid #000;padding:10px;text-align:left;\">Full bore<\/th>\n<th style=\"border:1px solid #000;padding:10px;text-align:left;\">Reduced bore<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #000;padding:10px;\">Pigging<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Normally preferred when the valve must pass the specified pig<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">May restrict or prevent pig passage<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #000;padding:10px;\">Pressure loss<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Lower local loss when fully open<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Higher velocity and pressure loss through the restriction<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #000;padding:10px;\">Size and mass<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Larger ball and body<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Can reduce envelope and mass<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #000;padding:10px;\">Selection rule<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Specify when pigging or minimum restriction is required<\/td>\n<td style=\"border:1px solid #000;padding:10px;\">Consider only after hydraulic and operational review<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Do not use \u201cfull port\u201d as an undefined sales phrase. State the required bore and pig-passage envelope on the data sheet and drawing.<\/p>\n<\/section>\n<section>\n<h2>DBB or DIB seat arrangement?<\/h2>\n<p>Double block and bleed (DBB) and double isolation and bleed (DIB) describe different isolation behavior. The purchaser should specify the required seat directionality and the pressure cases used to demonstrate it. The design review must also show how body-cavity pressure is relieved, because trapped liquid can expand when heated.<\/p>\n<p>Ask for a seat schematic that identifies upstream and downstream sealing directions, cavity relief path, drain and vent points, injection fittings and the effect of a failed seat. Avoid choosing a three-letter label without defining the actual isolation scenario.<\/p>\n<\/section>\n<section>\n<h2>Soft seat or metal seat for a pipeline ball valve?<\/h2>\n<p>A soft seat can provide tight shutoff with comparatively low torque when temperature, pressure, decompression behavior and fluid chemistry suit the polymer. Metal seats are considered for elevated temperature, abrasive solids, erosive service or duties that can damage polymers. A metal seat is not automatically better; leakage acceptance, surface treatment, operating torque and particulate tolerance must be agreed.<\/p>\n<p>For gas service, evaluate explosive decompression of elastomers and pressure-retaining seals. For crude oil or multiphase service, provide sand, scale and wax information. For sour service, specify the governing materials document and environmental limits rather than writing only \u201cNACE.\u201d<\/p>\n<\/section>\n<section>\n<h2>N\u00ean x\u00e1c \u0111\u1ecbnh k\u00edch th\u01b0\u1edbc c\u1ee7a b\u1ed9 truy\u1ec1n \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<\/h2>\n<p>Actuator selection starts with the manufacturer\u2019s torque curve, not a nominal valve size. Check break-to-open, running, end-to-close and maximum differential-pressure torque at the minimum available pneumatic, hydraulic or gas pressure. Apply the project safety factor and account for seat aging, low temperature, infrequent operation and any emergency operating-time requirement.<\/p>\n<p>Large pipeline valves may use electric, hydraulic, pneumatic or gas-over-oil actuators. Specify fail action, opening and closing times, local manual override, partial-stroke testing, position indication, control voltage, hazardous-area certification, enclosure rating and interface responsibilities. For a broader duty comparison, see WDL&#8217;s <a href=\"https:\/\/wdlvalve.com\/vi\/van-dau-khi-tren-bo\/\">onshore oil and gas valve selection guide<\/a> v\u00e0 <a href=\"https:\/\/wdlvalve.com\/vi\/van-dau-khi-ngoai-khoi\/\">offshore oil and gas valve guide<\/a>.<\/p>\n<\/section>\n<section>\n<h2>What should be checked for butt-weld ends and pup pieces?<\/h2>\n<p>Butt-weld valves need end chemistry, dimensions and weld-preparation details that match the line pipe and field welding procedure. Pup pieces can move field welding heat away from the valve body and simplify site fit-up, but their material, length, impact properties, welds and nondestructive examination must be specified.<\/p>\n<p>Agree whether the valve will be pressure tested before or after pup-piece welding, who supplies transition pieces, and how internal cleanliness and seat protection will be maintained. Field welding instructions should state valve position, temperature control and any limits needed to protect nonmetallic seals.<\/p>\n<\/section>\n<section>\n<h2>Which standards and tests belong in the order?<\/h2>\n<p><a href=\"https:\/\/www.iso.org\/standard\/86822.html\" rel=\"noopener\" target=\"_blank\">ISO 14313:2025<\/a> covers the design, manufacture, materials, welding, quality control, assembly, testing, documentation and process control of ball, gate, check, plug and axial valves for pipeline systems. ISO states that it supplements API 6D, 25th edition. The purchase order must state exactly which standard, edition, addenda and errata apply.<\/p>\n<p>Also define pressure testing, seat-leakage acceptance, fire-safe qualification, fugitive-emission requirements, sour-service materials, impact testing, NDE and third-party witnessing where applicable. A certificate number should be checked against the ordered design, material, size and pressure range; a generic claim is not enough.<\/p>\n<\/section>\n<section>\n<h2>Large diameter trunnion ball valve RFQ checklist<\/h2>\n<ol>\n<li>Line size, pressure class, design pressure and temperature.<\/li>\n<li>Fluid composition, water, H\u2082S, CO\u2082, solids and cleaning chemicals.<\/li>\n<li>Full or reduced bore, pig type and minimum passage.<\/li>\n<li>Side-entry or top-entry construction and body joint preference.<\/li>\n<li>DBB or DIB seat arrangement and cavity-relief direction.<\/li>\n<li>Soft or metal seats, leakage acceptance and fire-safe requirement.<\/li>\n<li>Flanged or butt-weld ends, line-pipe details and pup pieces.<\/li>\n<li>Actuator type, fail action, operating time, utilities and controls.<\/li>\n<li>Installation orientation, buried service, stem extension and coating.<\/li>\n<li>ITP, material certificates, calculations, drawings and final dossier.<\/li>\n<\/ol>\n<\/section>\n<aside style=\"border:1px solid #000;padding:18px;margin:24px 0;\">\n<h2>Request a project review<\/h2>\n<p>Send the line list, valve data sheet, piping class, actuator specification and inspection requirements. WDL Valve will review the requested configuration before quotation; final compliance depends on the approved order documents.<\/p>\n<p><a href=\"https:\/\/wdlvalve.com\/vi\/lien-he-voi-chung-toi\/\" style=\"display:inline-block;background:#1261ad;color:#fff;padding:12px 18px;text-decoration:none;\">Discuss a Trunnion Ball Valve RFQ<\/a><\/p>\n<\/aside>\n<section>\n<h2>Frequently asked questions about large diameter trunnion ball valves<\/h2>\n<h3>When is a trunnion-mounted ball preferred?<\/h3>\n<p>A trunnion-mounted ball is commonly preferred as size, pressure or required operating torque increases. The supported ball reduces pressure-driven seat loading compared with a floating design.<\/p>\n<h3>Are all large diameter ball valves full bore?<\/h3>\n<p>No. Full and reduced-bore designs exist. Specify the bore and pig-passage requirement rather than assuming it from valve size.<\/p>\n<h3>Can a trunnion ball valve throttle flow?<\/h3>\n<p>A standard pipeline isolation ball valve is generally intended for fully open or fully closed operation. Throttling requires a design and trim evaluated for velocity, noise, cavitation, erosion and control stability.<\/p>\n<h3>Why does cavity pressure relief matter?<\/h3>\n<p>Liquid trapped between closed seats can expand as temperature rises. The seat arrangement and relief direction must prevent unacceptable cavity overpressure while preserving the required isolation function.<\/p>\n<h3>What information controls actuator size?<\/h3>\n<p>The valve torque curve, maximum differential pressure, minimum actuator supply, operating time, temperature and project safety factor control actuator selection.<\/p>\n<\/section>\n<footer>\n<p><strong>Conclusion:<\/strong> Large diameter trunnion ball valves should be purchased as engineered packages, not enlarged commodity valves. Bore, seat philosophy, cavity relief, actuator torque, end preparation, logistics, testing and documents must be agreed before manufacture.<\/p>\n<p><strong>T\u00e1c gi\u1ea3:<\/strong> Wong WP, Gi\u00e1m \u0111\u1ed1c Kinh doanh, C\u00f4ng ty TNHH Van WDL H\u1ea1 M\u00f4n.<\/p>\n<p><small>GEO structure informed by Eugen Ullrich\u2019s LLM content framework, CC BY 4.0.<\/small><\/p>\n<\/footer>\n<\/article>","protected":false},"excerpt":{"rendered":"<p>Select large diameter trunnion ball valves for pipelines. Review bore, DBB, seats, actuation, pup pieces, testing and project documentation.<\/p>","protected":false},"author":1,"featured_media":1257,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[52],"tags":[],"class_list":["post-1421","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/posts\/1421","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/comments?post=1421"}],"version-history":[{"count":1,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/posts\/1421\/revisions"}],"predecessor-version":[{"id":1422,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/posts\/1421\/revisions\/1422"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/media\/1257"}],"wp:attachment":[{"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/media?parent=1421"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/categories?post=1421"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wdlvalve.com\/vi\/wp-json\/wp\/v2\/tags?post=1421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}