LESER GmbH & Co. KG D-20537 Hamburg, Wendenstrasse 133-135 D-20506 Hamburg, P.O.Box 26 16 51 Germany to be completed for your inquiries	Tel: Fax: e-mail: Internet:		049 251 65 100 0049 251 65 500 sales@leser.com www.leser.com
LESER - the company By tradition -always a step ahead "Loyalty by change". With almost 200 years of experience LESER ranks among the pioneers of mechanical engineering in Germany. The company, founded as a brass foundry in 1818, developed its first safety valves for the protection of steam boilers. Even at those days LESER products were designed to protect man and environment. As industrial development has been progressing very rapidly demands for safety valves have increased continuously too. Step by step LESER has developed its safety valves to reflect the state-of-the-art. The company has extended its product range to provide solutions for all sectors of this industry. Investment in research and development is therefore an important impetus for new developments at LESER and in this industry as a whole. LESER sets standards - now and in the future. With its 250 employees in Hamburg [1] and Hohenwestedt (Northern Germany) [2] LESER belongs to the leading manufacturers of safety valves worldwide. The product range comprises a total of 23 valve series (nominal diameter range DN 10 ...400 - NPS 1/2"...16") for applications in all branches of the industry. The annual production currently amounts to 60,000 safety valves. LESER is a member of VDMA, ASME and TÜV-Nord.
Type 441 / 442 444 Full Lift Safety Va/ves vrith flanged connections up to PN 40 / PR #300 Full lift safety valves open rapidly within an overpressure of 5% to the full design lift. They are used in particular for vapours and gases, in appli-cations where the maximum mass flow has to be discharged rapidly. LESER types 441/442/444 are suitable for almost any industrial applica-tion and belong to the best selling spring-loaded flange types of safety valves up to a pressure rating of PN 40/PR #300 worldwide. There are four series available: Type 4417442 DIN: Cast construction with DIN flanges [1]; four body materials: stainless steel, carbon steel, nodular and cast iron Type 4417442 ANSI: Cast construction with ANSI flanges[1]; two body materials: stainless steel and cast steel Centre to face length in accordance with API 526, greater discharge capacity than Standard API valves Type 4417442 "XXL": Robust welded construction [2] with DIN or ANSI flanges; weiding procedures to EN and ASME standards; two body materials: stainless steel and carbon steel Type 444: Welded construction using deep drawn body parts [3] (material: 1.4404/316L; plate thickness >4 mm); a principal characteristic feature is the smooth surface finish		DESIGN FEATURES • High discharge capacity in rela the inlet nominal diameter • Suitability for the relevant servi ditions is ensured by: - Six body materials (stainless carbon steel, stainless steel carbon steel castings, noduli cast iron) - A large variety of accessories - Closely graded flow ratings v wide range of nominal diame 14 steps (DN 20...400, NPS 3/4"...16") Applications: Chemical industry - Process protection (e.g., columns) - Equipment - Heat exchangers - Works supply Steam generators in industry - Water space - Steam drum Compressors - Blowers - Turbo compressors Pumps Mechanica! engineering (OEM) - Dying machines - Filter construction Power stations - Low and medium pressure steam - Condensers
Type 455/456 457/458 459M Safety Valves for high operating pressures >= PN 63/ PR #600 The LESER high pressure safety valves are full lift spring loaded safety valves which are used at high operating pressures (> 40 bar/> 580 psig), often in conjunction with high operating temperatures (> 400 °C/> 752 °F). The high pressure safety valves are designed to withstand these extreme service conditions through their robust construction, selection of materi-als, fit matching for the sliding parts, and the use of high temperature fit-tings. There are three series available: Type 455-456 "semi nozzle" [2]: Medium to large mass flows, high operating pressures (up to 100 bar/1450 psig), flanged connection Type 457-458 "full nozzle" [3]: Medium to very high mass flows, very high operating pressures (up to 400 bar/5800 psig), flanged connection or weiding stubs [4] Type 459M [1]: Small mass flows, very high operating pressures (250 ... 700 bar/3625...10150 psig), threaded, flanged or special connection (e.g., IG f lange)		DESIGN FEATURES • Valve body with brackets resp. ring grooves to provide fixing means to help support the valve and reduce the effect of reaction forces • Torque free adjustment of set pressur with play-free flat needie roller bearing • Bull race disc with lift aid which is detachable for ease of maintenance [5] • Discs with soft seals available up to 100 bar/1450 psig • Stellited, precision machined metal sealing surfaces [6] Applications: • Power stations and industrial superhea-ted steam generation - Drums - Superheaters - Economisers • Petrochemical industry - Protection of reactors and columns - Natural gas extraction and processing • Chemical plant - Process protection (e.g., NH3 synthesis, CO2 extraction) - Protection of pump stations and high pressure water systems • Compressor systems - Protection of compressors with high pressures and capacities • Desalination plants - Full nozzle in special materials
Type 526 Flanged Steel Pressure Reliel Valves according to API 526 Orifice D...T API 526 is a purchase specification in which nominal diameters [1], flange pressure ratings [2], centre to face dimensions [3], flow areas [4], body [5] and spring materials [6], and their service limits are stipulated for "API safety valves". API safety valves are used worldwide in the petrochemical industry, both on- and off-shore. These applications are characterised by standardised plants, blow-down systems and long pipework sections. The capacities of API safety valves are relatively low in relation to their nominal diameters.		DESIGN FEATURES • ASME-NB certified capacities • "Single trim" for steam/gases/liquids • Verslons with open and closed bonnets • Single part spindle, large guide spacings • Adjusting ring to alter the opening and reseating pressure differential ("blow-down-ring") • Back pressure compensating stainless steel ballanced bellows and compensation piston available fror 1 bar/15 psig [7] Applications: • Large scale chemical plant - Tank protection - Blow-down systems • Oil extraction, transport and processing - Drilling platforms - Oilfields ("Christmas trees") - Storage tank facilities - Refineries ---------------------------------------------------------------- The LESER type 526 combines the requirements of the API standards and the ASME Code with the tried and tested service reliability of the LESER product range.
Type 427/429 431/433 435/436 532/534 Relief and Safety Relief Valves with flanged connections Relief valves open in proportion to the pressure rise. They are used wher-ever normally expected mass flows are very small and the medium loss is to be kept as low as possible (e.g., thermal expansion). Safety relief valves are ideal relief valves for medium mass flows. Their large proportional range leads to consistent functioning and relief of pressure peaks, particularly with liquids. Both proportional and safety relief valves are characterised by particularly stable operation. There are four series available: Type 431/433: Safety relief valve spring loaded [1], cast construction with flanged connections for nominal pressure ratings up to PN 40/PR#150; three body materials: stainless steel, carbon steel and nodular cast iron Type 435/436: Safety relief valve spring loaded [1], cast construction with flanged connections for nominal pressure ratings up to PN 160/PR#600; two body materials: stainless steel and cast carbon steel Type 427/429: Relief valve spring loaded [1], cast construction with flanged connections; three body materials: stainless steel, carbon steel and nodular cast iron Type 532/534: In-line relief valve spring loaded, cast construction with flanged connections and in-line design [2]; two body materials: carbon steel and cast iron		DESIGN FEATURES • Adaptation to the relevant service conditions is ensured by: - A large range of additional accessories - Closely graded flow ratings with i wide range of nominal diameters in 11 steps (DN 15-150/NPS 1/2"...6") • Low overall height and low weight • The inlet nominal size is equal to th outlet nominal size Applications: Type 431/433 435/436 • Chemical industry - Production plants: low medium losses - Long pipework systems - Two phase flow - Waste gas cleaning systems (on the outlet side) • Heat transfer oil systems • Protection of liquids - Dosing/metering pumps - Hydraulic systems - Pulsating operating pressures • Mechanical engineering (OEM) - Reciprocating compressors of small and medium capacities Type 427/429 532/534 • Overflow functions • Thermal expansion - Protection of pipeline segments - Enclosed storage tanks
Type 437/438 459/462 Safety Valves with threaded connections Safety valves with threaded connections are used for handling small and medium mass flows. The LESER threaded connection safety valves are notable for their wide range of set pressures, compact overall dimensions and low weight. There are two series available: Type 437/438 Safety relief valve spring loaded [1] for small mass flows (e.g., thermal expansion and overflow); two body materials: chrome steel or stainless steel Type 459/462 Full lift safety valve spring loaded [2] for the medium mass flow range (e.g., small scale or pilot plant); two body materials: stainless steel or chrome steel/nodular cast iron Applications: • Carbon dioxide plants - Manufacture - Vaporisation - Processing • Technical gases - Air separation (cold box) - Cylinder filling • Refrigeration systems - 3K helium systems • Compressors - Diving air - Low, medium and high pressure systems • Steam generators - Flash steam generators - Firetube boilers • LPG/LNG - Terminals - Carriers • Pumps - Dosing/metering pumps - Overflow protection • Pipework protection - Pipelines - Chemical plants • Chemical installations - Technical centres - Reactors		DESIGN FEATURES: • Maintenance friendly with screwed ir nozzle[1] [2] • Metal sealing of all body parts • Variety of connections: - Thread: BSR BSPT, NPT - Flange [7]: DIN, ANSI, IG and speci; • Complete draining of the valve chamber • Short delivery periods, even for special materials Type 437/438 • Extremely compact dimensions • Two-part construction (inlet body and bonnet) • Design combines spring plate and spindle guide [3] • Attractive design, machined on all sides • Type 438: - Soft seal disc - Horizontal installation possible Type 459/462 • Smallest available safety valve with bellows [4] • Smooth surfaces, deep drawn from 5 mm thick plate • Improved leakproofness with enve-loping lift aid [5] • For p >250 bar g/3625 psig stellited sealing surfaces (seat/disc) • Type 462: Soft seal disc [6]
Type 447 546 449 Safety Valves for critical service In chemical plants critical service conditions and media may occur which place special demands on the design of safety valves, e.g., • Highly corrosive media • Highly toxic media • High back pressures LESER has developed three series of safety valves for these applications: Type 546: Safety valve with PTFE nozzle and protective coating in the outlet area for protection from highly corrosive media in systems with relatively rare acti-vation of the safety valve. The PTFE nozzle avoids product contam-ina-tion and adherence. By implementing stainless steel bellows operation with up to 50% back pressure is possible. Type 447: Safety valve with full PTFE lining for protection from highly corrosive media. The PTFE bellows is gastight and back-pressure compensated. Adherence is avoided by the smooth PTFE surfaces, (max. Rz 16 urn). Type 449: Safety valve in block form for protection from highly toxic media. A duet system for inert gas shrouding and analysis prevents the medium from getting into the atmosphere [4]. Applications: Type 546 • Multiple product systems Type 447 • Chlorine manufacture and processing • Reducing acids (e.g., hydrochloric acid, acetic acid) • Alkalis (e.g., NaOH solution) Type 449 • Phosgene systems • M Dl systems		DESIGN FEATURES Type 546: • Piped body: carbon steel or nodular cast iron • Nozzle: stabilised by support ring optionally in -PTFE - PTFE - carbon • Bellows: optionally - PTFE bellows - Stainless steel bellows • Sealing element: sealing disc in - Borofloat - glass (thermal shock resistant) - PTFE - carbon Type 447: • Piped body: cast steel • Lining: vacuum-proof, isostatic lini in virgin PTFE [2] • Seat nozzle: PTFE/glass sintered under inert gas • Nozzle, sealing disc and inlet bodi [3] can be replaced separately and are available in special materials fc specific applications Type 449: • Block body: Manufactured from a single block, material 1.4571 or sp cial materials such as Hastelloy
Type 411 421 522 543/544 440 424 450 460 Safety Valves according to special standards and regulations There are special rules and regulations in many countries for the pro-tection of land-based steam boilers, marine steam boilers and heating systems. These specifications are fulfilled by LESER's special series: Safety valves with lever and weight (Types 411 421 522) [1]: The main application for safety valves with levers and weights is the protection of land-based steam boilers. Further applications result from their small overall height and the ease of set pressure adjustment. Doublé safety valves (Types 543/544) [2]: Two independent safety valves - in some cases with a govern-ment ring - are specified for the protection of ship's boilers. In the constricted space on ships doublé safety valves fulfil this requirement ideally with only one connector on the steam boiler. Safety valves for heating plants, low pressure steam boilers (Types 424 440 450 460) [3]: For heating plants up to 120 °C and low pressure steam boilers up to 1 bar TRD 721 requires safety valves with soft sealing and elastomer bellows to protect the sliding parts.		DESIGN FEATURES Type 411 421 522: • Low overall height • Direct lifting • Simple adjustment of set pressure • Hardened edge guides Type 543 544: • Two independently functioning sa( valves • Common vessel connector • Common discharge pipe Type 440 460 and 424 450: • Fixed set pressure steps in the rar of 0,5 .... 10 bar • Elastomer bellows to profeet the sliding parts • Soft sealing o-ring disc
Type 310 311 Change-over Valves Change-over valves will be used if a plant shutdown is impossible or undesirable for process engineering or commercial reasons. With change-over valves it is possible to switch over between parallel safety valves without interrupting operation, so as, for example, to perform maintenance work. The design of the change-over valves ensures: • Low pressure losses on discharge flow (3% criterion) • Adequate open passage in any position during the change-over process • Stable operation of the downstream safety valves The combination [2] of LESER change-over valves and safety valves has been comprehensively tested on full flow test labs. There are two series available: Type 310: cast construction DN 25...50/NPS 1"...2" [1] Type 311: welded construction DN 80...400/NPS 3"...16" Applications: • Continuously functioning plant - Bitumen refineries - Oilfields - Ethylene plants • Non-drainable systems - Natural gas caverns, large storage facilities - Storage tanks for technical gases (e.g., ethylene reservoirs) • Application required by national standards - TRB 801 Nr. 14 for refrigeration systems - TRB 801 Nr. 26 for technical gases below -10°C - TRB 801 Nr. 27 for liquid gas systems		DESIGN FEATURES • Compact, low weight design • Full flow area on change-over • Flow area designed in such a way that no flow constriction takes plac and drag coefficients of resistance are therefore low: -Type 310 C= 0.6...1.0 -Type 311 C= 1.0...2.0 • Conical seal surfaces increase functional leak tightness • Optionally available with stuffing bc or stainless steel bellows with safei stuffing box Type 310: • Two body materials: cast steel and cast stainless steel • Can be combined with safety valve of the same nominal diameter [2] Type 311: • Two body materials: steel and stainless steel • Reducers can be directly welded on Accessories: - Pressure relief valve - Bypass with non-return valves - Limit switches