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Sizing Semi-Metallic Gaskets When Replacing Soft Gaskets When replacing soft gaskets with semi-metallic gaskets, it's important to understand the sizing differences and considerations. The following guidelines provide suggested dimensions based on experience to help you choose the appropriate non-metallic gasket size to replace a soft gasket. These sizings are not mandatory but serve as useful recommendations. 1. When Flange Dimensions Are Provided If the customer provides the dimensions of the flange, the following guidelines can be used to determine the appropriate gasket size: Gasket Inner Diameter (I.D.) : The inner diameter of the gasket should be the bore size of the flange plus a minimum of 1/8". Gasket Outer Diameter (O.D.) : The outer diameter can be up to the bolt hole circle diameter minus one bolt hole diameter. This applies when the proposed gasket width corresponds to the standard width of semi-metallic gaskets, which is typically 1/2", 3/4...

  Dimensionnement des Joints Semi-Métalliques en Remplacement des Joints Souples Lors du remplacement de joints souples par des joints semi-métalliques, il est important de comprendre les différences de dimensionnement et les considérations à prendre en compte. Les lignes directrices suivantes fournissent des dimensions suggérées basées sur l'expérience, afin de vous aider à choisir la taille de joint non métallique appropriée pour remplacer un joint souple. Ces dimensions ne sont pas obligatoires mais servent de recommandations utiles. 1. Lorsque les Dimensions de la Bride Sont Fournies Si le client fournit les dimensions de la bride, les lignes directrices suivantes peuvent être utilisées pour déterminer la taille appropriée du joint : Diamètre Intérieur du Joint (D.I.) : Le diamètre intérieur du joint doit être égal au diamètre de l'alésage de la bride plus un minimum de 1/8" (3,2 mm). Diamètre Extérieur du Joint (D.E.) : Le diamètre extérieur peut aller jusq...

Why use spiral wound gaskets ? Lotfi Grine, Eng. – Product Specialist at Robco Many types of industrial gaskets can be found in the field. Yet, the 2 most popular types of gaskets found are Spiral Wound Gaskets (SWG) and gaskets cut from calendered sheets. SWG are manufactured by spirally winding together a ‘V’ shaped metallic strip and a soft filler, generally g raphite. Calend e red S heet G askets are cut from sheets, which are manufactured by mix i ng, pressing and curing a composite of high temperature and chemically-resistant fibers, fillers and elastomers . Although in some cases, both type of gaskets can be used interchangeably, i t’s essential to choose the right gasket according to the application details. Why would you choose spiral wound gaskets? Benefits of Spiral Wound Gaskets SWG are capable of handling a significant part of the oil and gas industry applications . Below, we list some of advantages of spiral wound gaskets, so you can make a more informed decisi...

  Pourquoi utiliser des joints spiralés ? Lotfi Grine, ing. – Spécialiste de produit chez Robco On peut trouver de nombreux types de joints industriels sur le terrain. Cependant, les deux types de joints les plus populaires sont les joints spiralés (SWG) et les joints découpés dans des feuilles calandrées. Les SWG sont fabriqués en enroulant en spirale une bande métallique en forme de "V" et un matériau de remplissage souple, généralement du graphite. Les joints en feuilles calandrées sont découpés dans des feuilles fabriquées en mélangeant, pressant et durcissant un composite de fibres, de charges et d'élastomères résistant aux hautes températures et aux produits chimiques. Bien que dans certains cas, les deux types de joints puissent être utilisés de manière interchangeable, il est essentiel de choisir le bon joint en fonction des détails de l'application. Pourquoi choisir des joints spiralés ? Avantages des joints spiralés Les joints spiralés son...

  Compression contre charge : que devez-vous utiliser ? Lotfi Grine, ing. – Spécialiste de produit chez Robco  Une question courante concernant l'étanchéité avec des matériaux de joint plat est le pourcentage de compression approprié ou/et la quantité de charge nécessaire pour les comprimer. Il s'agit d'un paramètre de conception critique. Ces deux paramètres peuvent affecter le nombre, le type, la taille et l'espacement des fixations telles que les boulons pour empêcher la déviation du boîtier, la rotation de la bride et les fuites ultérieures. Étant donné que plusieurs matériaux de joint sont constitués d'un composite, comme les matériaux de joint semi-métalliques ou joint aux feuilles calandré, c'est le niveau de couple (charge) plutôt que le niveau de compression du joint exprimé en pourcentage qui compte. Ce niveau de couple sera choisi en fonction de différents paramètres tels que la qualité des boulons, le type de bride, la contrainte d'étanchéité ma...

  Compression versus Load: what should you use? Lotfi Grine, Eng. – Product Specialist at Robco One common question concerning sealing tightness with flat gasket materials is the proper compression percentage or/ and the amount of force needed to compress them. This is a critical design parameter. These two parameters can affect the number, type, size and spacing of attachments like bolts to prevent housing deflection, flange rotation and subsequent leakage. Because several gasket materials consist in a composite, like semi-metallic or compressed sheet gasket materials, it is the level of torque (load), rather than the level of gasket compression expressed in percentage that matters. T his level of torque will be chosen according to different parameters like bolts grade, flange type, maximum and minimum sealing stress, etc.  For Klinger compress sheets and gaskets, Robco uses KLINGERexpert software to assist users for improved scientific calculations of bolt torque requi...

Can flanges of various shapes be used together? Lotfi Grine, Eng. – Product Specialist at Robco Flat face flanges should never be bolted to a raised face flange. ASME B31.1 states that when connecting flat face cast iron flanges to carbon steel flanges, the raised face of the carbon steel flange must be removed and a full gasket is required. This is to prevent the cast iron flange (a thin, brittle material) from hanging in the space caused by the raised face of the carbon steel flange.   But there's a solution: if the flanges cannot be remanufactured, add a center ring between the raised face flange and the flat face flange. This ring carries one side with a raised face and another side with a flat face, and uses two gaskets. (Preferably a Maxiprofile type for the raised face).

  Peut-on utiliser ensemble des brides de diverses formes ?   Lotfi Grine, Eng. – Spécialiste de produit chez Robco Les brides à face plate (flat face) ne doivent jamais être boulonnées à une bride à face surélevée (raised face). L'ASME B31.1 indique que lors du raccordement de brides en fonte à face plate à des brides en acier carbone, la face surélevée de la bride en acier carbone doit être retirée et qu'un joint d'étanchéité complet est requis. Cela permet d'éviter que la bride en fonte (un matériel fin et cassant) ne soit suspendue dans l'espace provoqué par la face surélevée de la bride en acier carbone.   Mais il existe une solution :   Si les brides ne peuvent être réusinées, ajouter un anneau central entre la bride à face surélevée et la bride à face plate. Cet anneau porte un côté avec une face surélevée et un autre côté avec une face plane, et utilisent deux joints d'étanchéité, préférablement de type Maxiprofile.

  ASME PCC1-2019 : technical notes about sealing performance Lotfi Grine, Eng. – Product Specialist at Robco   In the following technical notes, you will find valuable technical extracts from the ASME PCC1 2019 ( bolted flange joint assembly (BFJA) guidelines) to help better understand sealing behaviour and produce a positive seal. - Calculating Target Torque Values are based on the root area. The root areas are based on coarse-thread series for sizes 1 in. and smaller with 8-pitch thread series for sizes 1 1/8  in. and larger (Section H). - The major long-term value of coated bolts is to protect against corrosion of the exposed threads and to minimize break-out and nut-removal torque, thereby promoting ease of joint disassembly (Section 7). - Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code requires that nuts engage the threads for the full depth of the nut (Section 8.2).   - Start-up re-torque is performed when the temperature of ...

Choosing the right type of stainless-steel grade to use for spiral wound gaskets is important. Lotfi Grine, Eng. – Product Specialist at Robco The media concentration, temperature and time requirements provide a variety of work conditions for spiral wound gaskets.   The metal components are subject to different types of attack, including pitting, cracking, stress corrosion cracking and intergranular corrosion. It’s important to specify, that the standard stainless-steel used for Robco SWG is normally Type 316L . Other high quality alloys are available (ex : hastelloy, inconel, monel, etc.) for higher temperature or other special applications Here are the particularities of stainless-steel grades used generally in the manufacturing of spiral wound gaskets: Stainless steel type 304 serves a wide range of applications. It resists organic / inorganic chemicals. The main limitation of Type 304 is stress corrosion cracking and intergranular corrosion when the temperature exceeds 800°...

Lotfi Grine, Eng. – Product Specialist at Robco   Causes for bolts to loosen in service: ·         Vibration: it’s an unintentional loosening, and it is the repeated relative displacements between the contact surfaces resulting in relative motion occurring in the threads. ·         Gasket creep: the gasket loses its springiness over time; it is also a permanent deformation and It’s more severe in high-temperature applications. ·          Elastic interactions between multiple bolts: Elastic interactions can either increase or decrease bolt preload. ·         Temperature fluctuation caused as a result of either differences in temperature or differences in clamped materials. ·          Low preload developed at installation: it occurs when there is no sufficient clamp force (under-tightened bolt) present on the joint interface to prevent relative motion...

Style Selection Guide of Metallic Serrated Maxiprofile Gasket: Lotfi Grine, Eng. – Product Specialist at Robco Standard core design is parallel, which offers the advantage of even stress distribution across the gasket face. The LA2 type is used for Male & Female and Tongue & Groove type flanges without outer ring type. LA1 and LA2 types are used for flat face and raised face type flange. Sizes: Standard sizes are offered to fit ASME B16.20 to suit ASME B16.5, ASME B16.47 series A and B pipe flanges. Other non-standard gasket sizes are also available.       Maxiprofile STYLE Cross Section Flange Type Flat Face  Raised Face  Male and Female Tongue and Groove  LA2 Core only-without outer ring.     √ √ LA1 Integral outer ring √ √ ...