SAFETY VALVES atmosphere. For this reason, during relief, a gas leak occurs through this orifice. Utilized material: EN CW617N brass.

Transcription

1 Safety devices

2 SAFETY VALVES 3030 GENERAL DESCRIPTION Valves series 3030 are safety devices according to the definition given in Article 1, Point 2.1.3, 2nd dash of 97/23/EC Directive and are the subject of Article 3, Point 1.4 of aforesaid Directive. The valves above mentioned are standard tye, unbalanced, direct-loaded safety valves. Valve oening is roduced by the thrust the fluid under ressure exerts on the disc, when said thrust exceeds, under setting conditions, the oosing force of the sring acting on the disc. Valves are identified by means of: a model number formed of an alhanumerical coding that includes: in the first art the family identification (e.g. 3030/44C); in the second art the setting ressure, exressed in bars, multilied by 10 (e.g. 140); an alhanumerical serial number. CONSTRUCTION Body: squared, obtained through die forging and subsequent machining. It houses the following elements: the nozzle with flat sealing seat; the disc guide; the setting sring holder; the threaded seat of the setting adjusting ring nut. In the body, above the disc guide, a small ressure relief hole is rovided through which the sring holder is ut into contact with the TABLE 1: General Characteristics of valves 3030 Connections Catalogue number 3030/44C 3030/66C 3030/88C Flow Diameter [mm] Flow Section [mm 2 ] Lift [mm] Discharge Coefficient Kd PS [bar] TS [ C] Set Pressure Range [bar] Overressure Inlet male Outlet male Blowdown Risk category according to PED 1/2" 3/4" G ,1 3/4" 3/4" G ,1 1" 1.1/4" G 19, ,8 0,90 0,90 0, / / 50 5% of set ressure 15% of set ressure IV atmoshere. For this reason, during relief, a gas leak occurs through this orifice. Utilized material: EN CW617N brass. Disc: obtained through bar machining and equied with gasket, it ensures the required sealing degree on the valve seat. The gasket is made in P.T.F.E. (Polytetrafluorethylene), a material that, during valve estimated service life, maintains a good strength and does not cause the disc to stick on the seat. The disc is roerly guided in the body and the guide action can never fail; there are no glands or retaining rings that hamer the movement thereof. Utilized material: EN CW614N brass. Sring: it ooses the ressure and the fluid dynamic actions and always ensures valve reclosing after ressure relief. The sring coils, when the disc has reached the lift corresonding to the state of relief at full flow rate, are saced aart by at least half the wire diameter and, in any case, by not less than 2 mm. The disc is equied with a mechanic lock and when it attains it, the sring set does not exceed 85% of the total set. Utilized material: DIN steel for srings. Setting system: hexagonal head, threaded ring nut to be screwed inside the body to by comressing the sring below. On setting comletion, the osition attained by the ring nut is maintained unchanged laying, in the threaded couling, a bonding agent with high mechanic strength and low viscosity features to make enetration thereof easier. The setting system is rotected against subsequent unauthorized interventions by means of a ca nut that is screwed outside the body and is sealed with Castel lead to it. 50

3 TABLE 2: Dimensions and Weights of valves 3030 Dimensions [mm] Catalogue Weight number [g] Ø D L Ch H 1 H 2 H /44C 3030/66C 3030/88C SCOPE Use: rotection against ossible overressures of the aaratuses listed below, with regard to the oerating conditions for which they have been designed: refrigerating system and heat um comonents, for instance: condensers, liquid receivers, evaorators, liquid accumulators, ositive dislacement comressor discharge, heat exchangers, oil searators, iing (reference: EN 378-2: 2008); simle ressure vessels (reference: 87/404/ EEC Directive) D Ch L H2 H1 H3 Fluids: the valves can be used with: refrigerant fluids, in the hysical state of gas or vaour, belonging to Grou II according to the definitions of 97/23/EC Directive, Article 9, Point 2.2 (with reference to 67/548/EEC Directive of June 27th, 1967); air and nitrogen (reference: 87/404/EEC Directive). MARKING In conformity with the rovisions of Article 15 of 97/23/EC Directive, the EC marking and the identification number of the notified body involved in the roduction control hase are reorted on the valve body. Still on the body, the following information is indicated: manufacturer s mark, address and manufacture country; valve model; flow section; Kd discharge coefficient; indication of flow direction; max allowable ressure; allowable temerature range; set ressure; roduction date; serial number. safety devices such as safety valves. Such devices shall revent ressure from ermanently exceeding the max allowable ressure PS of the equiment they rotect. In any case, a short ressure eak limited to 10% of admissible maximum ressure is ermitted. As to the selection and sizing of the suitable rotection device, users shall refer to the secific sector or roduct standards. EN 378-2: 2008 Standard Refrigerating systems and heat ums safety and environmental requirements Part 2: Design, construction, testing, marking and documentation, harmonized with 97/23/EC Directive, rovides a general outline of the rotection devices to be adoted in refrigerating systems and their features (ar 6.2.5). It also indicates the criteria for the selection of the device suitable to the tye and sizes of the system comonent to be rotected (ar ). EN 13136: 2001/A1: 2005 Standard Refrigerating systems and heat ums Pressure relief devices and their associated iing Methods for calculation highlights the ossible causes of overressure in a system and makes available to users the instruments for ressure relief device sizing, among which the safety valves. VALVE SELECTION 97/23/EC Directive requires that ressure equiment, in which ermissible limits are reasonably likely to be exceeded, shall be fitted with suitable rotection devices, for instance 51

4 SIZING OF SAFETY VALVES DESIGNED TO DISCHARGE GAS OR VAPOUR AT CRITICAL FLOW (Ref. EN 13136: 2001/A1: 2005) Critical flow occurs when the backressure b (the ressure existing immediately at the outlet of a safety valve) is below or equal to the critical ressure: [bar abs] with: o = actual relieving ressure, ustream the safety valve; it s equal to the set ressure lus overressure. That is a ressure increase over set ressure at which the disc has its total lift. [bar abs]; k = isentroic exonent of gas or vaour, based on the actual flowing conditions at the safety valve inlet. If k is unknown or anyway difficult to establish it s ossible to suose: [bar abs] A safety valve, which discharges to atmoshere, works in critical flow. The safety valves designed to discharge gas or vaour at critical flow must be sized as follow: A b critical c 2 o k + 1 = 05, k k 1 Qmd = 3, 469 C 09, K [mm 2 ] with: A c = minimum flow area of safety valve [mm 2 ]; Q md = minimum required discharge caacity, of refrigerant, of safety valve [kg/h]; K d = certified coefficient of discharge; o = actual relieving ressure, ustream the safety valve, see definition above [bar abs]; v o = secific volume of gas or vaour at relieving conditions o e T o meaning with T o fluid temerature at valve inlet, settled by the user or by the designer [m 3 /kg]; C = function of isentroic coefficient k calculated from: 2 C = 3, 948 k k + 1 o d ( k + 1) ( k 1) v o o for this calculation the value of k shall be as measured at 25 C. (Section 7.2.3, Standard EN 13136: 2001/A1:2005). Values of k and calculated values of C for some refrigerants are given in table A.1 of the aforesaid standard. Following we show the values of k and C for the more useful refrigerants. Calculation of minimum required discharge caacity of safety valve is closely linked to the tye of system where the valve is installed, with the causes that may arouse the oening of safety valve, i.e.: external heat sources. The minimum required discharge caacity shall be determined by the following: Q Refrigerant R22 R134a R404A R407C R410A R507 md [kg/h] with: = density of heat flow rate, it s assumed to be 10 [kw/m 2 ]; A surf = external surface area of the vessel [m 2 ]; h va = heat of vaorization of liquid at o [kj/kg]; internal heat sources. The minimum required discharge caacity shall be determined by the following: 3600 Qh [kg/h] Qmd = h with Q h = rate of heat roduction [kw]. Excessive ressure caused by comressors. The minimum required discharge caacity shall be determined by the following: Q = V n ρ η [kg/h] md 3600 ϕ A = h va va Isentroic coefficient k 1,17 1,12 1,12 1,14 1,17 1,10 surf v Function of Isentroic coefficient C 2,54 2,50 2,50 2,51 2,54 2,48 52

5 with: V = theoretical dislacement of comressor [m 3 ] n = rotational frequency of comressor [min 1 ] ρ 10 = vaour density at refrigerant saturation ressure / dew oint at 10 C [kg/m 3 ] η v = volumetric efficiency estimated at suction ressure and discharge ressure equivalent to the safety valve setting. EXAMPLE OF CALCULATION OF MINIMUM REQUIRED DISCHARGE CAPACITY Q md AND SIZING OF THE SAFETY VALVE FOR THE HIGH PRESSURE SIDE OF A REFRIGERATING SYSTEM System descrition Comact refrigerating system designed to make refrigerated water and consisting of: oen tye recirocating comressor; water-cooled, shell-and-tube horizontally condenser with lower section of shell used as receiver; shell-and-tube horizontally liquid cooler fed with a thermostatic valve; refrigerant fluid R407C. Comressor data Bore 82,5 mm Stroke 69,8 mm Cylinder number 6 Rotational frequency 1450 rm Clearance 4% The theoretical dislacement of comressor is: π 2 V = 0, , = 0, [m 3 ] Maximum allowable ressure of the condenser, refrigerant side: PS = 25 bar. Set ressure of the safety valve installed on the uer shell section of condenser: set = 25 bar Actual relieving ressure of safety valve, choosing one valve tye 3030 with an overressure of 5%: 5 = =, 0 set 1 [bar abs] These conditions, settled in any case by the designer, are considered the most unfavorable for the safety valve in consequence of functional defects as: move mistake; non-working of automatic safety devices, set to oerate before safety valve. It shall be excluded: closeness the refrigerating system, the resence of flammable substances in so large quantities to be able to feed a fire.; inside the vessel, the resence of a heart source. Calculation of minimum discharge caacity Prudentially leaving the vaour overheating at the outlet of the liquid cooler out of account, the volumetric efficiency of comressor is: discharge 27, 25 η v = 1 0, 04 = 1 0, 04 = 083, suction 633, and so the minimum required discharge caacity: Q = V n ρ η = md = 60x0,00224x1450x26,34x0,83 = 4260 [kg/h] with ρ 10 = 26,34 [kg/m 3 ], vaour density of R407C at saturation ressure / dew oint at 10 C. v Working conditions of comressor corresonding to the relieving of safety valve: Condensing temerature: + 64 C (27,25 bar abs) Evaorating temerature: + 10 C (6,33 bar abs) 53

6 Sizing of minimum flow area of the safety valve A c Qmd = 3, 469 C 09, K , 0104 = 3, 469 = , 09, 083, 27, 25 d vo = o [mm 2 ] with: C = 2,51, corresonding to isentroic exonent k for R407C equal to 1,14, according to table A1 of standard EN 13136:2001/A1:2005; K d = 0,83, certified coefficient of discharge for safety valve 3030/88; v o = 0,0104 [m 3 /kg], secific volume of overheating vaour ustream the safety valve during relieving. This value is referred to the following oerating conditions, ustream the safety valve: ressure o = 27,25 [bar abs]; temerature T o = 100 [ C] (recautionary temerature, settled in any case by the designer). Conclusion: the selected safety valve is the model 3030/88 with the following characteristics: certified coefficient of discharge, Kd = 0,83; flow section, A c = 298 [mm 2 ]; set ressure, set = 25 bar. In case of single-screw comressor with injection of ressurized oil, the theoretical dislacement is: V c = π D 4 2 L [m 3 ] with: D = rotor diameter [m] L = rotor length [m] 54

7 VALVE INSTALLATION As far as the installation of safety relief valves is concerned, the fundamental oints listed below shall be taken into account: safety valves shall be installed near an area of the system where vaours or gases are resent and there is no fluid turbulence; the osition shall be as uright as ossible, with the inlet connector turned downwards; vessels, joined together with iing rightly selected by the manufacturer and without any sto valve between them, may be considered as only one vessel for the installation of a safety valve; the union between the valve and the equiment to be rotected shall be as short as ossible. Furthermore, its assage section shall not be narrower than the valve inlet section. In any case, EN 13136: 2001/A1:2005 Standard states that the ressure loss between rotected vessel and safety valve, at discharge caacity, shall not exceed 3% of the setting value, including any accessory mounted on the ustream line; in selecting the safety valve location, it shall be taken into account that valve oeration involves the discharge of the refrigerant fluid under ressure, sometimes even at high temerature. Where the risk exists to cause direct injuries to the ersons nearby, an exhaust conveying iing shall be rovided, which shall be sized in such a way as not to comromise valve oeration. EN 13136: 2001/A1:2005 Standard states that this iing shall not generate, at discharge caacity, a back ressure exceeding 10% of ressure o, for standard tye valves, unbalanced. To calculate the ressure loss either in the ustream line (between vessel and safety valve) or in the downstream line (between safety valve and atmoshere) refer to EN 13136: 2001/A1:2005 Standard, Chater 7.4. Pressure loss in the ustream line Calculation of ressure loss is given by: Δ o in 2 A = 0, 032 C Kdr A ζ in with: A = flow area of safety valve [mm 2 ]; A in = inside area of inlet tube to valve [mm 2 ]; K dr = K d x 0,9, derated coefficient of discharge; C = function of isentroic coefficient k; ξ = addition of ressure loss coefficients ξ n of any comonent and iing; The coefficients ξ n are relevant to: ie elements loss, as connections and bends; valves loss; loss along the ie and are listed in EN 13136:2001/A1:2005 Standard, Table A.4. Examle: assume to install, on the condenser of the revious examle, a safety valve tye 3030/88, set to 25 bar, using a steel union with the following characteristics: d in = 28 [mm], inside diameter; A in = 616 [mm 2 ], inside area; L = 60 [mm], length; flush connection to the shell of condenser, with a broken edge. From table A.4 it s ossible to have these data: ξ 1 (inlet) = 0,25 ξ 2 (length) = λ x L/ d in = 0,02 x 60/28 = 0,043 with λ = 0,02 for steel tube ξ T = ξ 1 + ξ 2 = 0,25 + 0,043 = 0,293 Between safety valve and union it s installed a shut-off valve tye 3033/88 (see age 59). The main characteristics of this valve are: d R = 20 [mm], inside diameter; A R = 314 [mm 2 ], inside area; kv = 20 [m 3 /h], kv factor. Pressure loss coefficient ξ R of shut-off valve is given by: ζ R = , = 0, 64 The total ressure loss coefficient is: ξ T + ξ R = 0,933 We remember the main characteristics of safety valve 3030/88 and of refrigerant fluid R407C: A = 298 [mm 2 ] K dr = 0,83 x 0,9 =0,747 C = 2,51 Pressure loss in the ustream line is: 2 Δin = , 2, 51 0, , 933 = 0, 0245 o 2 55

8 The obtained value is admissible because lower than the value of 0,03 forecast in EN 13136:2001/A1:2005 Standard. Pressure loss in the downstream line Calculation of ressure loss is given by: with: - P 1 = inlet ressure to downstream line [bar ass] - P 2 = outlet ressure to downstream line, equal to atmosheric ressure [bar ass] - A = flow area of safety valve [mm 2 ] - A out = inside area of outlet tube to valve [mm 2 ] - K dr = K d x 0,9, derated coefficient of discharge - C = function of isentroic coefficient k - P o = actual relieving ressure, ustream the valve [bar abs] - ξ = addition of ressure loss coefficients ξ n of iing The coefficients ξ n are relevant to: - ie elements loss, bends - loss along the ie and are listed in EN 13136:2001//A1:2005 Standard, Table A.4. Examle: assume to install a discharge ie on safety valve tye 3030/88 of the revious examle, using a steel tube nominal size 2 with the following characteristics: - d out = 53 [mm], inside diameter - A out = 2206 [mm 2 ], inside area - L = 3000 [mm], length - ie bend 90 with bending radius R equal to three times external diameter of tube From table A.4 it s ossible to have these data: - ξ 1 (bend) = 0,25 - ξ 2 (length) = λ x L/ d in = 0,02 ξ 3000/53 = 1,13 with λ = 0,02 for steel tube - ξ T = ξ 1 + ξ 2 = 0,25 + 1,13 = 1,38 Pressure loss in the downstream line is: The obtained value is admissible because lower than the value of 0,10 forecast in EN 13136:2001/A1:2005 Standard. [bar] 56

9 SAFETY VALVES 3060 ressure relief duct is rovided through which the sring holder is ut into contact with the outut connection. Utilized material: EN CW617N brass. Disc: obtained through bar machining and equied with gasket, it ensures the required sealing degree on the valve seat. The gasket is made in P.T.F.E. (Polytetrafluorethylene), a material that, during valve estimated service life, maintains a good strength and does not cause the disc to stick on the seat. The disc is roerly guided in the body and the guide action can never fail; there are no glands or retaining rings that hamer the movement thereof. Utilized material: EN CW614N brass. GENERAL DESCRIPTION Valves series 3060 are safety devices according to the definition given in Article 1, Point 2.1.3, 2nd dash of 97/23/EC Directive and are the subject of Article 3, Point 1.4 of aforesaid Directive. The valves above mentioned are standard tye, unbalanced, direct-loaded safety valves. Valve oening is roduced by the thrust the fluid under ressure exerts on the disc, when said thrust exceeds, under setting conditions, the oosing force of the sring acting on the disc. Valves are identified by means of: a model number formed of an alhanumerical coding that includes: in the first art the family identification (e.g. 3060/45C); in the second art the setting ressure, exressed in bars, multilied by 10 (e.g. 140); an alhanumerical serial number. Sring: it ooses the ressure and the fluid dynamic actions and always ensures valve reclosing after ressure relief. Utilized material: DIN steel for srings. Setting system: hexagonal head, threaded ring nut to be screwed inside the body to by comressing the sring below. On setting comletion, the osition attained by the ring nut is maintained unchanged laying, in the threaded couling, a bonding agent with high mechanic strength and low viscosity features to make enetration thereof easier. The setting system is rotected against subsequent unauthorized interventions by means of a ca nut that is housed into the brass body and is fixed in this seat with an edge calking oeration. CONSTRUCTION Body: squared, obtained through die forging and subsequent machining. It houses the following elements: the nozzle with flat sealing seat; the disc guide; the setting sring holder; the threaded seat of the setting adjusting ring nut. In the body, above the disc guide, a small 57

10 TABLE 3: General Characteristics valves 3060 Catalogue number 3060/23C 3060/24C 3060/33C 3060/34C 3060/45C 3060/36C 3060/46C Connections inlet male outlet male 1/4" 3/8" SAE 1/4" 1/2" SAE 3/8" 3/8" SAE 3/8" 1/2" SAE 1/2" 5/8" SAE 3/8" 3/4" G 1/2" 3/4" G Flow Diameter [mm] 7,0 9,5 10,0 Flow Section [mm 2 ] 38,5 70,9 78,5 Discharge Coefficient Kd 0,63 0,69 0,63 0,69 0,45 0,92 0,93 PS [bar] 55 TS [ C] - 50 / St Pressure Range [bar] 9 / 50 Overressure 10% of set ressure Risk Category according to PED IV SCOPE Use: rotection against ossible overressures of the aaratuses listed below, with regard to the oerating conditions for which they have been designed: refrigerating system and heat um comonents, for instance: condensers, liquid receivers, evaorators, liquid accumulators, ositive dislacement comressor discharge, heat exchangers, oil searators, iing. (reference: EN 378-2: 2008); simle ressure vessels (reference: 87/404/ EEC Directive). Fluids: the valves can be used with: refrigerant fluids, in the hysical state of gas or vaour, belonging to Grou II according to the definitions of 97/23/EC Directive, Article 9, Point 2.2 (with reference to 67/548/EEC Directive of June 27 th, 1967); Air and nitrogen (reference: 87/404/EEC Directive). MARKING In conformity with the rovisions of Article 15 of 97/23/EC Directive the following information are reorted on the valve body: manufacturer s mark, address and manufacture country indication of flow direction max allowable ressure set ressure allowable temerature range roduction date serial number The following data are stamed on the ca: EC marking and the identification number of the notified body involved in the roduction control hase valve model flow section Kd discharge coefficient VALVE SELECTION 97/23/EC Directive requires that ressure equiment, in which ermissible limits are reasonably likely to be exceeded, shall be fitted with suitable rotection devices, for instance safety devices such as safety valves. Such devices shall revent ressure from ermanently exceeding the max allowable ressure PS of the equiment they rotect. In any case, a short ressure eak limited to 10% of admissible maximum ressure is ermitted. As to the selection and sizing of the suitable rotection device, users shall refer to the secific sector or roduct standards. EN 378-2: 2008 Standard Refrigerating systems and heat ums safety and environmental requirements Part 2: Design, construction, testing, marking and documentation, harmonized with 97/23/EC Directive, rovides a general outline of the rotection devices to be adoted in refrigerating systems and their features (ar 6.2.5). It also indicates the criteria for the selection of the device suitable to the tye and sizes of the system comonent to be rotected (ar ). EN 13136: 2001/A1:2005 Standard Refrigerating systems and heat ums Pressure relief devices and their associated iing Methods 58

11 for calculation highlights the ossible causes of overressure in a system and makes available to users the instruments for ressure relief device sizing, among which the safety valves. For sizing and installation of safety valves series 3060 see the revious chater of safety valves series ØD H2 H3 Ch H1 L Catalogue number TABLE 4: Dimensions and Weights of valves 3060 Dimensions [mm] Ø D L Ch H 1 H 2 H 3 Weight [g] 3060/23C 21, ,5 46, /24C 21, ,5 46, /33C 21, ,5 46, /34C 21, ,5 46, /45C 24,5 39, , /36C ,5 96, /46C ,5 99,5 380 BALL SHUT-OFF VALVES FOR SAFETY VALVES APPLICATIONS We would like to remember to our customer that the running of ressure equiments and ressure assemblies is excluded by the scoe of Directive 97/23/EC but it s regulated in comliance with national regulations of Member States of Euroean Communities. We think that these regulations, actually on udating with the Cometent Bodies of all the states to avoid conflicts with the ESR of PED, could rovide for eriodical checks on the ressure equiments and assemblies. Any intervention for eriodic checking or relacement of an installed safety valve becomes very difficult if the rotected vessel is not equied with a shut-off valve. The shut-off valves series 3033 and 3063, installed between vessel and safety valve, allow to remove the valve for eriodic checking or relacement without blowing off all the refrigerant from a section of the system. These valves can be used with the same fluids foreseen for safety valves series 3030 and 3060, in articularly: refrigerant fluids, in the hysical state of gas or vaour, belonging to Grou II according to the definitions of 97/23/EC Directive, Article 9, Point 2.2 (with reference to 67/548/EEC Directive of June 27 th, 1967); air and nitrogen (reference: 87/404/EEC Directive). CONSTRUCTION Castel sulies to its customers the valves series 3033 and 3063 in oen osition and the ball sindle is rotected by means of a ca screwed to the body and sealed with lead to it. Any closing intervention on the valve forcedly causes the tamering of the seal and then these interventions shall be erformed exclusively by: 59

12 staff authorized to work on the system; ublic servant of a Cometent Body. These ersons will be resonsible for the next valve reoening and the new ca sealing with their own lead. The main arts of these valves are made with the following materials: hot forged brass EN CW 617N for body; hot forged brass EN CW 617N, chromium lated, for ball; steel, with roer surface rotection, for the sindle; P.T.F.E. for seat ball gaskets; chlororene rubber (CR) for outlet seal gaskets; glass reinforced PBT for ca that covers the sindle. SEAL VALVE 3030/.. BALL VALVE 3033/.. SEAL TABLE 5: General Characteristics, dimensions and Weights of valves 3033, 3063 Catalogue number Designed for valve Kv Factor [m 3 /h] min TS [ C] max PS [bar] Dimensions [mm] Ø D A C L H 1 H 2 H 3 Weight [g] Risk Category according to PED 3063/ /45C 3060/46C /2" ,5 84, / /44C Art / /88C " CHANGEOVER DEVICES FOR SAFETY VALVES APPLICATIONS The changeover device tye 3032 is a service valve for dual ressure relief valves that allows using one valve while isolating the other from the system. This device allows the user to work on the isolated valve, for eriodic checking or relacement, while the system is comletely oerative and the other valve is in service. N.B.: each safety valve laced on a changeover device must have sufficient caacity to rotect the vessel alone. Valve tye 3032/44 is sulied with: two female threaded connections 1/2 with swivel nut, code Castel 3039/4; two O-Ring. These comonents ensure the erfect alignment of two safety valves 3060/45. The valves series 3032 can be used with the same fluids foreseen for safety valves series 3030 and 3060, in articularly: refrigerant fluids, in the hysical state of gas 60

13 or vaour, belonging to Grou II according to the definitions of 97/23/EC Directive, Article 9, Point 2.2 (with reference to 67/548/EEC Directive of June 27 th, 1967); air and nitrogen (reference: 87/404/EEC Directive). CONSTRUCTION The valve 3032 is designed so that it is never ossible to close off both orts at the same time, excluding all the two safety valves. Under working conditions, the shutter must be clamed against one of the two seats of the valve, front ort or back ort, in order to ensure always full discharge to the corresonding safety valve. Intermediate ositions of the shutter are not accetable in order not to affect the oeration of both safety valves. The valve ensures a ressure dro erfectly comatible with the safety valve oeration under conditions of discharge of saturated vaour as well as overheated vaour. The main arts of these valves are made with the following materials: hot forged brass EN CW 617N for body; steel, with roer surface rotection, for the sindle; chlororene rubber (CR) and aramidic fibers for gland seal; chlororene rubber (CR) for outlet seal gaskets; glass reinforced PBT for ca that covers the sindle. TABLE 6: General Characteristics, Dimensions and Weights of valves 3032 Catalogue number Designed for valve Kv Factor [m 3 /h] min TS [ C] max PS [bar] D A B Dimensions [mm] H 1 H 2 L 1 L 2 L 3 Weight [g] Risk Category according to PED 3032/ /45C 3060/46C 3,3 13 1/2" 1/2" / / /44C 3030/66C 9,0 9, ,5 17,5 3/4" 3/4" 1/2" 3/4" Art / / /88C 14,5 20,0 22,0 31, /4" GASKET 61

14 SAFETY VALVES UNIONS Unions series 3035 allow assembling safety valves series 3030 and 3060 or shut-off valves series 3032, 3033 and 3063 close to the ressure equiments to rotect, set u in a refrigerating system. These unions are designed for installations according to the following two ways: Make a coer tube jointing the ressure equiment to the union, fit the end of this tube into the solder connection of the union and then make a caillary brazing. Drill the inner/outer ie close to the ressure equiment (if ossible make a collar on the ie), ut the end of the union into this drill and then make a braze welding. The unions series 3035 are machined by brass bar EN CW614N coer Tubo di rame tube Coer tube TABLE 7: General Characteristics, Dimensions and Weights of unions 3035 Connections Dimensions [mm] Catalogue number ODS Ø [mm] PS [bar] D L Ch Weight [g] 3035/2 1/ /3 3/ , ,5 3035/4 1/ /6 3/ / /10 1.1/4"

15 FUSIBLE PLUGS GENERAL DESCRIPTION Fusible lugs series 3080/.C and 3082/.C are safety devices according to the definition given in Article 1, Point 2.1.3, 2 nd dash of 97/23/EC Directive and are the subject of Article 3, Point 1.4 of aforesaid Directive. According to the definition given in Point of EN 378-1:2008 Standard, fusible lug is a device containing material that melts at a redetermined temerature and thereby relieving the ressure. Castel has resolved to classify fusible lugs series 3080/.C and 3082/.C in the Category of Risk I therefore fixing their use, as rotection devices, on secific ressure equiments, roer to the same Category of Risk I, in comliance with Annex II, Point 2, of 97/23/EC Directive. In consequence of this choice, fusible lugs series 3080/.C and 3082/.C cannot be used, as sole rotection devices, on ressure equiments roer to Categories of Risk higher than first. CONSTRUCTION The body of the fusible lug is an lug drilled with a taer hole. A redetermined quantity of fusible alloy, with checked melting oint, is oured inside this hole. The arts of the fusible lugs are made with the following materials: Brass EN CW 614N, hot tinned, for the lug. Eutectic alloy with several comonents, cadmium and lead free, for the fusible material. SCOPE Use: the fusible lugs are basically used to rotect the comonents in a refrigerating system or heat um against ossible overressures, with regard to the oerating conditions for which they have been designed, in case of an excessive external heat source, such as fire. Fluids: the fusible lugs can be used with refrigerant fluids belonging to Grou 2 according to the definitions of 97/23/EC Directive, Article 9, Point 2.2 (with reference to 67/548/EEC Directive of June 27 th, 1967). MARKING In conformity with the rovisions of Article 15 of 97/23/EC Directive and of Point of EN 378-2:2008 Standard the following data are reorted on the hexagonal nut: EC marking; Manufacturer's logo; Max allowable ressure PS; Melting oint. INSTALLATION If a fusible lug is mounted on a ressure vessel or any other art which it rotect it shall be laced in a section where suerheated refrigerant would not affect its correct function. Fusible lug shall not be covered by thermal insulation. Discharge from fusible lugs shall take lace so that ersons and roerty are not endangered by the released refrigerant. EN 378-2:2008 Standard, harmonized with the 97/23/EC Directive, establishes that a fusible lug shall not be used as ressure relief device on vessels containing refrigerants roer to A2, B1, B2, A3 e B3 grous. The same Standard establishes that a fusible lug shall not be used as the sole ressure relief device between a refrigerant containing comonent and the atmoshere for systems with a refrigerant charge larger than 2,5 kg of grou A1 refrigerant (ex. R22; R134a; R404A; R407C; R410A; R507). FUSIBLE PLUG SELECTION 97/23/EC Directive requires that ressure equiment, in which ermissible limits are reasonably likely to be exceeded, shall be fitted with suitable rotection devices, for instance safety devices such as fusible lugs. Such devices shall revent ressure from ermanently exceeding the max allowable ressure PS of the equiment they rotect. In any case, a short ressure eak limited to 10% of admissible maximum ressure is ermitted. As to the selection and sizing of the suitable rotection device, users shall refer to the secific sector or roduct standards. EN : 2008 Standard Refrigerating systems and heat ums safety and environmental requirements Part 2:Design, construction, testing, marking and documentation rovides a general outline of the rotection devices to be adoted in 63

16 refrigerating systems and their features (ar 6.2.5). It also indicates the criteria for the selection of the device suitable to the tye and sizes of the system comonent to be rotected (ar.6.2.6). EN : 2001/A1:2005 Standard Refrigerating systems and heat ums Pressure relief devices and their associated iing Methods for calculation, harmonized with 97/23/EC Directive, highlights the ossible causes of overressure in a system and makes available to users the instruments for ressure relief device sizing, among which the fusible lugs. SIZING OF FUSIBLE PLUG (REF. EN 13136: 2001/A1:2005) As the fusible lugs discharge to atmoshere, they always work in critical flow (to know the definition of critical flow, see the chater of safety valves series 3030). The fusible lugs must be sized as follow: A c Q md = 3, 469 C K dr v [mm 2 ] with: A c = minimum flow area of fusible lug [mm 2 ] Q md = minimum required discharge caacity, of refrigerant, of fusible lug [kg/h] K dr =derated coefficient of discharge of fusible lug, equal to 0,9 x K d o = ressure ustream the fusible lug, inside the equiment to be rotected [bar abs] v o = secific volume of gas or vaour at relieving conditions o e T o,[m 3 /kg] (T o is the fluid temerature at lug inlet, settled by the user or by the designer) C = function of isentroic coefficient k (as measured at 25 C, see Section 7.2.3, EN : 2001/A1:2005 Standard) calculated from: o o ( k+ 1) 2 ( k 1) C = 3, 948 k k + 1 To find the values of k and C for the more useful refrigerants, see the chater of safety valves series 3030 Calculation of minimum required discharge caacity of fusible lug is closely linked to the main cause that may arouse the oening of fusible lug, which is the external heat source. The minimum required discharge caacity shall be determined by the following: 3600 ϕ Asurf Q [kg/h] md = h va with ϕ = density of heat flow rate, it s assumed to be 10 [kw/m 2 ] A surf = external surface area of the vessel [m 2 ] h va = heat of vaorization of liquid at o [kj/kg] EN : 2001/A1:2005 Standard also establishes that the following values for K dr shall be the maximum used deending on how the ie between the vessel and the fusible lug is mounted on the vessel: flush or flared connection: K dr = 0,70 inserted connection: K dr = 0,55. TABLE 8: General Characteristics, Dimensions and Weights of fusible lugs 3080 e 3082 Catalogue number Connections Flow Diameter [mm] Flow Section [mm 2 ] Kd PS [bar] Melting oint [ C] Hexagonal Key Wrench Torque min/max [Nm] Weight [g] Risk Category according to PED 3080/1C 1/8" 4,9 18, / /2C 3080/3C 1/4" 3/8" 5,7 8,5 25,5 56, / / /4C 3082/1C 1/2" 1/8" 9,3 4,9 67,9 18,8 0, / 30 7 / I 3082/2C 3082/3C 1/4" 3/8" 5,7 8,5 25,5 56, / / /4C 1/2" 9,3 67, /