Robco Expert

  In the process of gasket material selection, many inquiries point to the term “fire-safe”. Lets briefly look at the two most commonly used gasket fire testing methods: API 6FA & API 607. API 6FA: The American Petroleum Institute’s 6FA-re test is used to qualify valves for chemical process service.  The flange is assembled using proper bolt-up procedures and all parameters such as stress and torque are recorded. Thermocouples are mounted 1” away from the outside of the flange (Figure 1). The valve is enveloped in flame using four propane burners arranged symmetrically around the outside of the flange. The flame temperature should be 1400ºF to 1800ºF (average of the two thermocouples) for a burn period of 30 minutes from ignition. The temperature is maintained with no reading less than 1300ºF. An internal water pressure amounting to 75% of the flange rating is applied throughout the test and the leakage rate is continually measured. The test rig is then allowed t...

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.

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°...

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 √ √ ...