NON-RETURN FLAP VALVE MODEL NOREX (unidirectional valve)

Transcription

1 NON-RETURN FLAP VALVE MODEL NOREX (unidirectional valve) Installation, maintenance and user manual for DN800-DN1000 Norex valves Manual number: MAN_NOREX_ _SI_En_13_03 Manual compiled in conformity with enclosure II paragraph of ATEX directive 94/9/EC StuvEx Safety Systems Ltd Tel.: ISMA Abbey Studio, Church Walk, Fax.: StuvEx Chertsey, Surrey, KT13 8RE IExT England

2 Updates Date Page Changes 12/03/2013 all Original 03/04/2013 all General revision 18/04/ , 13, 15, Updated the information about the locking mechanism Added one page with dimension of the flanges 29/04/ Completed the picture of the tag plate with ATEX number All information contained in this document is the exclusive intellectual property of STUVEX International nv BELGIUM. No element of any nature may be transmitted or otherwise given to any third party or person with our prior written permission. This manual contains important information. The manual should be studied and understood carefully before undertaking any activity on any part of a StuvEx system or a StuvEx system in general. If a StuvEx system is not treated and/or installed according to the instructions in this manual, StuvEx can be no means be held responsible for the consequences in any way. Please check carefully if any pages in this manual are missing. If so, please contact StuvEx or its acknowledged representative. In this manual the name StuvEx refers exclusively to StuvEx International nv in Belgium. 2

3 Table of Contents 1. NORMS AND GENERAL INFORMATION... 4 SYMBOLS IDENTIFICATION OF THIS DOCUMENT PURPOSE OF THIS INSTRUCTIONS MANUAL GENERAL INSTRUCTIONS AND MANUFACTURER S LIMITED RESPONSIBILITY STORAGE OF THIS INSTRUCTIONS MANUAL MANUFACTURER IDENTIFICATION DATA WARRANTY TECHNICAL OR MAINTENANCE ASSISTANCE FOR THE SYSTEM OBLIGATIONS AND DUTIES EMPLOYER S DUTIES OBLIGATIONS IN CASE OF INTERVENTION OBLIGATION TO RESPECT REGULATIONS OBLIGATIONS IN CASE OF MALFUNCTION AND POTENTIAL DANGER CUSTOMER S OBLIGATIONS INTRODUCTION TO ATEX DIRECTIVES EXPLOSIVE ATMOSPHERES GENERAL ACCIDENT PREVENTION PRESCRIPTIONS ADDITIONAL RISKS DESCRIPTION OF THE PROTECTIVE SYSTEM TRANSPORT AND STORAGE OF NOREX VALVES INSTALLATION OF NOREX ISOLATION VALVES CHECK UP AND PERIODIC MAINTENANCE CHECK UPS DISASSEMBLY AND SCRAPPING DRAWINGS

4 1. Norms and General Information Symbols The following symbols are used in this manual to focus costumer s attention on: : EXPLOSIVE ATMOSPHERES DANGER This symbol directs attention to prescriptions or indications relevant to the ATEX 94/9/EC directive. Operations with regard to this symbol must be executed by highly qualified personnel, competent in safety themes relevant to zones with a potentially explosive atmosphere. : DANGER / ATTENTION This symbol is used for pointing out operations potentially harmful to the operators. Carefully follow the information indicated beside this symbol before proceeding with these operations. : INDICATION This symbol is used to point out operations which require special attention. Please respect the information beside this symbol before proceeding with these operations. : CAUTION / PRUDENCE This symbol is used to supply useful instructions or special information while executing certain operations. It is advised to follow the supplied instructions before proceeding with these operations Identification of this document This instructions manual is a document issued by StuvEx and is an integral part of the protective system. This manual should be kept for future reference. All rights for reproduction and publication of this document or quoted information are reserved. Copyright by StuvEx Purpose of This Instructions Manual The main purpose of this instructions manual is to supply the customer and his personnel with the necessary information to correctly install the system, interact with the system and use it and maintain it in optimum conditions. It is recommended to strictly observe safety precautions during installation, operation, service and repair of the valve. Every person in the user's plant who is engaged in assembling, disassembling, commissioning, operating or maintaining (inspection, service or repair) the valve must have read and understood these entire operating instructions. The user is recommended to have this confirmed in writing. 4

5 1.3. General Instructions and Manufacturer s Limited Responsibility StuvEx has thoroughly analysed all interactions between the operator and the protective system in case the system is used for its intended purpose. Experience, suitable training and good sense of the people working with the system have been taken into account. In addition to studying this manual these are indispensable qualities for working with this system. Do not make any modifications, additions or conversions to the system that could affect safety without consulting manufacturer. Replacement parts must meet the technical requirements specified by manufacturer. This will be guaranteed by using genuine replacement parts. Any use apart from StuvEx instructions, is considered not to be for the intended purpose. The manufacturer is not liable for any resulting loss or damage to equipment or people. This risk is borne solely by the user. Use for intended purpose also includes complying with manufacturer's instructions for installation and conditions for commissioning, operating and maintenance Storage of This Instructions Manual This document is an integral part of the system and has to be kept for reference during its entire operational life, even if the system is transferred to a third party. Requests for multiple copies of this manual can be made with StuvEx customer service. To preserve this document, please: Use it in such a way as not to damage its content, do not drop it during use and always store in its designated place after consultation. Do not remove, tear or rewrite any part of this manual. You may request copies at StuvEx. Store the manual away from humidity, heat and other environmental agents that may compromise its integrity Manufacturer Identification Data This protection device is manufactured by StuvEx in conformity with current legislation by means of following acts: Declaration of conformity according to addendum X point B of ATEX 94/9/EC. ATEX marking plate on valve Instructions Manual 5

6 Product ID serial number Arrow indicating airflow direction Product series Model & DN Year of construction Maximum air flow Max explosion indexes of the handled dust Maximum reduced explosion pressure Explanation of markings: II D: explosive atmosphere due to presence of dusts (D = Dust) 1.6. Warranty For information on warranty please consult the draw up of the initial sales conditions Technical or Maintenance Assistance for the System In case an intervention is required please contact StuvEx. In case the customer does not respect what is indicated in present publication, we don t respond for inconveniences or anomalies in the correct operation of the equipment. 6

7 2. Obligations and Duties 2.1. Employer s Duties The employer is responsible for supplying the contents of this document to all personnel that will work in the process this system is protecting Obligations in Case of Intervention The operators dealing with this protective system are obliged to adequately study this manual and adhere to relevant specific safety regulations before executing any intervention to the system Obligation to Respect Regulations The operators are obliged to adopt and respect general accident prevention prescriptions stipulated in community and/or national legislation Obligations in Case of Malfunction and Potential Danger The operators should signal the person directly responsible whenever a possible deficiency and/or dangerous situation require verification. If needed contact StuvEx Customer s Obligations Customer is obliged to inform StuvEx if he finds any defects or malfunctions, as well as when he learns of any presumably dangerous situation. It is strictly forbidden to customer and/or third party (duly authorized StuvEx personnel excluded) to modify or overhaul the valve as well as to modify this manual. In case of malfunction or danger due to misuse or maltreatment of the system as mentioned above, StuvEx will not be liable for any consequences. Should you wish to make alterations to the system, please contact StuvEx directly. 7

8 3. Introduction to ATEX Directives 3.1. Explosive Atmospheres ATEX directive 94/9/EC is intended for explosive atmospheres consisting of a mixture: Inflammable substances in gaseous states, vapors, mists and dusts With air In specific atmospheric conditions In which, after ignition, the combustion is propagated to the mix that is not burnt (please notice that in presence of dust, the combustion does not always consume the entire quantity of dust present) An atmosphere that is susceptible to transformation into an explosive atmosphere due to local and/or operation conditions is defined as a potentially explosive atmosphere. These are the specific types of atmosphere the products manufactured according to directive 94/9/CE are designed for. With reference to presence of explosive atmospheres the European Union has issued two directives, one relevant to the construction safety prescriptions of ATEX 94/9/EC products, the other relevant to the safety prescriptions in the working environment: ATEX 99/92/EC. In function of the probability of explosive atmospheres being present, the working environment is classified in zones, in which instruments conforming to the safety requisites of these respective zones may be installed and used. The schedule below indicates the product category suitable for installation in different zones: GAS G Zones DUSTS D Probability of Formation of Explosive Atmospheres Constant presence or for long periods Occasional during normal operation Constant presence or for long periods Occasional during normal operation Very rare and/or short in duration during normal operation Protection Level Very elevated Elevated Product Category Group I M1 M2 Group II Very elevated 1 Elevated 2 Normal 3 8

9 4. General Accident Prevention Prescriptions Customer and operators are obliged to respect and adhere to accident prevention regulations in effect, both in the legal and business levels. In particular it is asked to respect following rules: All working personnel should not at any time be under the influence of sedatives, drugs or alcohol and should be perfectly aware of the operation s characteristics It is absolutely forbidden to disable, open or remove the valve during operation Connect the protective system to the plant s grounding and maintain equipotentiality amongst the parts of the system without inserting any other parts in its configuration that are not described in this manual In case maintenance needs to be performed, make sure that the process in which the system is installed is stopped Always use original replacement parts During maintenance or any other action requiring disassembly of the process installation in which the valve is incorporated, it is obliged to place a special sign on the parts that are being disassembled (interrupters, disconnected switches, valves, etc.) prohibiting anyone to reactivate the machinery. If possible it is recommended that these parts are closed off by (pad)locks. It is allowed to use this protective system in plants in which ignition of a potentially explosive atmosphere can t be reduced to a tolerable minimum according to directive 99/92/EC in presence of dusts Preferably operators in the classified areas should wear anti-static clothes, if possible in a natural fibre Possible interventions in the areas classified as potentially explosive should be carried out using tools that cannot produce sparks Do not use compressed air systems to clean the interstices since the only effect is that dust will be lifted to fall out and create new deposits. Please use an aspiration system The process installation to which the non-return flap valve is mounted should be connected to an efficient grounding system, in order to be able to disperse possible electrostatic currents The protective system should be installed respecting relevant safety regulations regarding the protection of equipment and people 9

10 It is strictly forbidden to use flames or open fire in the proximity of the process to which the protective system is mounted and in every working zone in general Smoking is strictly prohibited Use of cell phones not marked ATEX and not belonging to the working installation in the classified hazardous area is prohibited according to directive 99/92/EC. 10

11 5. Additional Risks The accurate analysis of the risks by the manufacturer as listed in the technical brochure ensures that most risks associated with the valve usage have been eliminated. The manufacturer recommends to meticulously follow the instructions, procedures and recommendations described in this manual and to adhere to valid safety regulations. Additional risks associated with the application of this valve may be: Risk of wrong interpretation of the safety pictograms The manufacturer has provided safety tags on the valve, in accordance with relevant regulations concerning the graphic symbols. The user should replace illegible and/or damaged safety tags immediately. ATTENTION It is absolutely forbidden to remove the safety tags from the valve. The manufacturer is not liable in any way if this prohibition is not observed. 11

12 6. Description of the Protective System The non-return flap valves with counterweight and locking mechanism of the series NOREX, are designed by StuvEx for isolation of dust explosions. They have to be used as an ATEX protection system in accordance with the applicable European Directive. They are capable to isolate a deflagration between a vessel and the interconnected system. Concerning the protective systems for isolation of dust explosions identified as non-return flap valves series NOREX produced by StuvEx, this manual addresses following issues: - Evaluation of the risks associated with the use of the protective system in potentially explosive atmospheres - Conformity of the protective system with the minimum requirements concerning health and safety subjects described in directive 94/9/CE. The counterweight system with locking mechanism consists of a moving bar with counterweight and it is fixed to the flap by a breaking element having a pre-determined rupture point. The scope of the counterweight is to balance the flap. The scope of the breaking element is to determine the separation between the moving bar with the counterweight and the flap when an instantaneous force/pressure acts on the flap. After the rupture of the breaking element, the counterweight is blocked in a support specifically fixed on the body of the valve. The scope of the locking mechanism is to block the flap in case of explosion and prevent any possible backflow or backfiring. This series NOREX consists of 3 different sizes of explosion isolation non-return flap valves. They only differ in diameter size. The basic philosophy of isolating an explosion leads to the system s objective: to avoid propagation of the pressure wave and flame produced by an explosion. By this methodology it is possible to isolate in a process, a vessel and the interconnected systems. The non-return flap valves for explosion isolation are passive systems, so they do not need a detection system nor controls or functional indicators. These valves, same as the pipes where they have to be installed, need to be selected for the maximum reduced explosion pressure (P red max ) expected during the explosion. The distance between the vessel where the explosion is to be expected and the non-return flap valve, directly depends on the maximum speed of flame front propagation and of the protective system s response time. The main factors that influence the performances of an explosion isolation system are: - Explosion characteristics of the dust - Type of explosion protection installed as protection of the vessel to be isolated - Diameter, length and mechanical resistance of the pipes - Air speed of the mixture (dust+air) inside the pipes - Speed of the flame front - Closing time of valve. The speed of the flame front, taking into account the airflow inside the pipe, is: V F = V airflow +S F where: V F total speed of the flame front [m/s] V airflow air speed in the pipe [m/s] S F speed of the flame front in absence of airflow in the pipe [m/s] 12

13 The NOREX non-return flap valves are for explosion isolation; they are made in carbon steel thickness 30/10mm or 40/10mm (depending on the nominal size of the valve). Optionally they are available also in stainless steel. Technical characteristics of the DN800-DN1000 Norex series non-return flap valves: Model Norex 800 Norex 900 Norex 1000 Max. admitted reduced explosion pressure P red max [bar] Distance between the vessel to be isolated and the Norex valve [m] 0,25 3 0,25 3 0,25 3 K st max A B C D E F G H kg 299 [bar.m/s] 299 [bar m/s] 299 [bar m/s] dwg. 1 outline dimensions eyebolts Iid lifting handles grounding counterweights (2x) grounding D N inspection door locking mechanisms in safety block (2x) The ambient conditions in which the non-return flap valve may be installed are limited to 60 C and a relative humidity of 90%. The non-return flap valve is a thermic passive object, its maximum surface temperature depends entirely on the process to which it is mounted. 13

14 7. Transport and Storage of Norex Valves Every Norex non-return flap valve is equipped with an external fitting flange. To avoid damage during transport the valve is protected by polystyrene inserts. Before unpacking the non-return flap valves, please verify the integrity of the package and if it corresponds to the equipment ordered by checking the order documentation. Open the package on one side and remove the valve from its box, taking care not to damage it. Verify its integrity by removing all the polystyrene inserts and checking the state of the valve. Once its integrity is verified, put the non-return flap valve back in its box until the moment of use. Packed this way, store the valve in a dry place. Shelter it from atmospheric influences or other possible causes of damage. 14

15 8. Installation of Norex Isolation Valves The protective systems of the Norex series are fit to operate under the expected conditions as specified on the tags fixed to the valve and the CE declaration of conformity (static pressure activation, characteristics of the ambient environment, nature and state of processed dusts, etc.). ATTENTION The installation of the protective system must be performed in absence of a potentially explosive atmosphere by stopping the plant s process. Wear individual protection devices Directions for installation - The direction of the airflow during the normal process should respect the direction of the arrow depicted on the identification label - The inspection hatch should always be set upward - The valves come equipped with eyebolts for lifting (necessary due to the relevant weight) The installation distance from the vessel to be isolated is equal to 3 meters. The non-return flap valve series Norex may be installed in an area where the maximum explosion reduced pressure, reduced by the installation of explosion venting devices, will not exceed the P red max value of 0.25 bar as indicated on the tag plate. - Make sure that the valve is supported or otherwise thoroughly kept in place. - Fix the flanges on the entry and exit sides of the valve to the flanges on the piping in which the explosion may take place. Respect the flow direction on the tag plate and in the dwg. 3 on page Connect the ground cables of the non-return flap valve to the aspiration pipe with 4 mm cable. PLACEMENT AND INSTRUCTION TO ASSEMBLE THE COUNTERWEIGHTS (refers also dwg. 2, page 16) ATTENTION! For safety reasons and means of reducing bulk during transport, the counterweights are shipped separated from the diaphragm pin. 1. Unscrew the bolt (4), insert the moving bar (1) with the counterweight (3) and fix again the bolt (4) and the washer (5). 2. Check that the distance (A) of the counterweight (3) from the pin centre is: mm for DN800 valve; mm for DN900 valve; mm for DN1000 valve. 3. To fix the breaking element (B): - block the fixed bar (2) in the safety block by the locking mechanism; - take the moving bar (1) with the counterweight in line of the fixed bar (2) and insert the pin fixed to a chain (E) on the holes of flanges (D-D1) s that the moving bar (1) stay fixed to the fixed bar (2); - fix the breaking element (B) to the 2 holes (C) on flanges (D-D)1 with M5 screws (C) using hexagonal key 4 mm (pay attention to avoid any damage of the breaking element); 15

16 - raise a little bit the moving bar (1) and - IMPORTANT - remove the pin (E) and leave slowly the moving bar (1) with the counterweight in order to prevent any damage of the breaking element. Pay attention not to damage the breaking element, handle with care, is calculated to break with an overload of 5 6 kg. The non-return flap valve is manufactured with the flap divided in two parts and a central terminal cross bar. In order to be able to inspect the inside of the valve on materials that may interfere with its function, it is recommended to inspect regularly the valve from the side inspection door. IMPORTANT: Before starting aspiration, release the 2x locking mechanisms in safety blocks (see dwg. 1, page 13). Attention: significant sudden changes in pressure may damage the breaking elements and consequently they need to be replaced. Rupturing of the breaking elements reduces the passage of air in the pipe without causing any damage to the customer s plant. dwg. 2 detail of the (2x) moving bars with breaking elements DETAIL X X Effect the connection of mass to earth of the non-return flap valve in the points depicted in the following pictogram. Personnel performing the installation should use anti-spark utensils ATTENTION Personnel performing the installation should wear dissipative clothing and footwear Antistatic clothes: clothes made of a material with superficial resistance of less than 5x10 10 Ω Antistatic footwear: footwear that guarantees to a person standing on a conductive or dissipative floor a resistance towards earth superior to 10 5 Ω, but less than 10 8 Ω. 16

17 To render the pressure relief as effective as possible, the non-return flap valve must be placed in proximity of the area or the zone in which the explosion will take place, giving the flame front the most direct trajectory with the least number of obstacles. Only qualified personnel adequately educated in the content of this manual is allowed to perform installation of the Norex non-return flap valve. This safety device must be installed according to the manufacturer s instructions and in no way should any of its parts be modified. dwg. 3 flow direction horizontal mounting, only 17

18 9. Check Up and Periodic Maintenance Attention: before starting any check-up or intervention on the non-return flap valve it is imperative that the equipment it protects is not under pressure and inside there are no substances which may produce an explosive, toxic or otherwise harmful atmosphere. The lifespan of a Norex non-return flap valve usually depends on the conditions it is submitted to once in use in the customer s plant. A visual check on the integrity of the valve and its parts is not sufficient to determine the condition of the apparatus. In all cases a visual check should be done every month to identify possible corrosion, breaks or deformation that may influence the valve s correct functioning. In addition verify that the gasket seal is still intact and check if all screws and couplings on the valve are still tightened well. ATTENTION Maintenance and cleaning of the valve must always be executed in absence of potentially explosive atmospheres by stopping the plant s process Check periodically the breaking elements. In case of failure and/or rupture, these elements need to be promptly replaced. From operational point of view, this will reduce the airflow of the aspiration system and might jeopardize the safety function of the valve. In case of explosion, it is necessary to open the upper inspection lid, verify the status of the flaps and of the other moving parts. In case damages are noted, please refer to the manufacturer of the plant. In case of positive results of the inspection, it is necessary to replace the breaking elements fixing the counterweights (about position of the counterweights, refer to paragraph 6). 18

19 10. Check Ups Operation to perform Frequency Procedures Verify state and tightness of nuts Verify the state of the valve Verify the earth connection of the protective system Periodically verify that there are no excessive dust accumulations in the valve Verify status of the breaking elements and operation of the locking mechanisms monthly Visually check possible breakings, releases and vibrations during operation Check opening and closing with the counterweights; in case of doubt, open the upper lid and inspect the inside of the valve. When finished, close and tighten the nuts with torque wrench 40 Nm When finished, verify that the locking mechanisms are released 19

20 11. Disassembly and Scrapping In case the Norex non-return flap valve is to be dismantled all the materials must be disposed of in suitable dumping sites in accordance with local legislation. Before proceeding with the scrapping of the valve, please separate the plastic and rubber parts from the metallic materials. The parts constituted of just plastic, aluminium or steel can be recycled if left at the right dump site. 20

21 12. Drawings dwg. 4 flange dimensions 21