Robco Expert

What gasket material to use on sheet metal flanges for ventilation systems Jocelyn Vachon - VP B.Dev / Product Specialist Gasket materials require to be compressed, in order to achieve a seal. What materials should you use when flanges are simply made of thin sheet metal? Ventilation systems assembled on-site require gaskets between sections. Sheet metal flanges cannot create a high, evenly dispersed mechanical load on gasket materials, even if internal pressures are low (6 to 12 inch of water on average).   Here are a few suggestions: Closed cell sponges with a durometer of 20 to 60 (shore 00 scale) are good options Neoprene-based sponges (Robco SC-41 soft / SC-42 medium / SC-43 firm) are the most popular. Self-adhesive strips can be formed (round flanges) or cut in lengths (square flanges) for a quick and wasteless assembly PTFE saturated woven glass tapes (Robco GW-305) can be used where temperatures are above 250°F (130°C) and where a ...

   ASME PCC1-2019 : notes techniques sur les performances d'étanchéité Lotfi Grine, Eng. – Spécialiste de produit chez Robco   Dans les notes techniques suivantes, vous trouverez de précieux extraits techniques de l'ASME PCC1 2019 (directives d'assemblage de brides boulonnées (BFJA)) pour aider à mieux comprendre le comportement d'étanchéité et produire une étanchéité positive.   - Le calcul des valeurs de couple cible est basé sur la zone racine. Les zones de racine sont basées sur une série de gros filetages pour les tailles de 1 po et moins avec une série de pas de filetages de 8 pour les tailles de 1 1/8 po et plus (section H).   - La principale valeur à long terme des boulons revêtus est de protéger contre la corrosion des filetages exposés et de minimiser le couple de rupture et de retrait d'écrou, facilitant ainsi le démontage des joints (Section 7).   - La section VIII, division 1 du code ASME sur les chaudières et les appareils à pression e...

  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°...

  DO NOT MACHINE COLD OR HOT THERMOPLASTICS by: RedOps / Robco When receiving thermoplastic sheets, rods, tubes, etc... Do not begin machining them until they have been allowed to sit at room temperature 24 hours. This will allow the thermoplastic to regain its nominal dimensions. This is inherent in thermoplastics, since they expand and contract with temperature.

  HOW TO WRAP PIPE WITH HIGH TEMPERATURE TAPE by: RedOps / Robco Rule of thumb is wrapping the tape for the first turn around, then start the second wrapping halfway over the first and continue this pattern for the entire tape wrapping of the pipe length.   This will create a double wrapping of the pipe and this is the best practice for protection. Just as you would do on a hockey stick!

OVER GREASING KILLS BEARINGS  by: Red Ops / Robco ·      Overfilling bearings with grease is the most common cause of bearing failures. ·      Too much grease in the cavity/bearing will cause more friction to run the bearing and that will result in an increased temperature to levels above the drop point of the grease: oxidation will occur and both the grease and bearing will prematurely fail! ·      Follow the instructions of the bearing manufacturer for greasing quantities as per bearing type and size. ·      Take into consideration the environment, temperature and operating hours.   OVER GREASED BEARINGS PROPERLY GREASED BEARINGS

Both strong with low water absorption and good electrical insulation.  FR-4 (or FR4) is a NEMA grade designation for glass-reinforced epoxy laminate material. FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant (self-extinguishing). "FR" stands for flame retardant, and does not denote that the material complies with the standard UL94V-0 unless testing is performed to UL 94, Vertical Flame testing in Section 8 at a compliant lab. The designation FR-4 was created by NEMA in 1968. FR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate grade with good strength to weight ratios. With near zero water absorption, FR-4 is most commonly used as an electrical insulator possessing considerable mechanical strength. The material is known to retain its high mechanical values and electrical insulating qualities in both dry and humid conditions.  Meets MIL-I-24768/27. G-10 is a high-pressure fibr...

  What does “K” factor mean for Insulation? Thomas Cipriani – Product Specialist at Robco The K factor expresses the amount of heat transferred by a chosen material at a specific temperature. The higher the temperature, the higher the amount of heat is transferred. To determine the K Factor, we use the Thermal Conductivity rating of the material or ability to conduct heat. Usually, insulation materials have a K Factor of less than one. The lower the K factor, the better the insulation. HOT face / COLD face: Exposed side / absorbed heat. When we know the temperature of exposure and the Thermal Conductivity of the material we can determine the temperature on the outside of the insulation that will be exposed. _____________________________________________________________________ Que signifie le facteur « K » pour l'isolation ? Thomas Cipriani - Spécialiste produit chez Robco Le facteur K exprime la quantité de chaleur transférée par un matériau choisi à une...

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...

Is there a rule of thumb to measure the proper amount of cooling water leakage , when using braided packing on rotary equipment (ex: pumps, agitators, mixers, etc.) ?  Jocelyn Vachon - VP B.Dev / Product Specialist In order for braided compression packing to seal and work properly on a dynamic equipment, water is injected through a flush line and distributed inside the stuffing box by a lantern ring. A small amount of this water will therefore leak out from the stuffing box.  The objective is twofold : A positive pressure of clean water has to be created inside the stuffing box, to prevent process fluid from entering the stuffing box To minimize frictional heat, by creating a hydrodynamic lubricating film between the stationary packing rings and the rotating shaft. This is a balancing act between how much compression is exerted on the packing rings set, to reduce to a minimum process fluid leakage versus limiting frictional heat. A...

Whenever Biosoluble wool insulation is an option for your application, go for it. There are many reasons why. Here are the main 8 benefits of Biosoluble Fibre. Text & photo: Jean Melançon - Robco 1. Excellent thermal insulation properties  A Biosoluble needled blanket shows comparable heat loss than a ceramic blanket of the same thickness. 2. No binder The needling process doesn’t require any binder nor transfer lubricant onto the fibers. 3. Good thermal stability Thermal stability is good for a vast array of applications. 4. Low thermal accumulation It offers a low heat storage index and most Biosoluble fibers demonstrate a low shot content. 5. Excellent resistance to most corrosive substances Very good resistance to various chemicals (except phosphoric and hydrofluoric acids and concentrated bases and solvents) 6. Very good flexibility and resilience Very flexible and malleable it allows easy handling and installation and has good resilience to compression. It can be die-cut ...

  Pressure capability guidelines: There are many gaskets materials type, and the pressure ability to withstand for each materials type is different. It starts from low pressure for soft gasket material up to high pressure for metallic and semi-metallic gaskets. So, according to the pressure level high or low we need choose the right gasket material to create a reliable seal. The chart below provides a guide to the suitability of our materials in standard ANSI flanges. Note: It should be noted that the ability to withstand assembly load is also dependent on the temperature of the application, and therefore gasket selection must be cheked with the pressure/temperature graphs given for each material. We use Klinger reference of material styles because those are the ones we know best. Materials Class 150 (20 bar) Class 300 (50 bar) Class 600 (100 bar) Class 900 (155 bar) Class 1500 (260 bar) Class 2500 (4...