■Notes to be observed in design and usage■
▼Notes to be observed in design
・Determine the number and size of bolts and gasket dimensions to provide gaskets with sufficient tightening stress, and also design the construction so as to ensure uniform distribution of tightening stress.
・Determine the construction, material and dimensions so that the flange is not likely to cause rotation.
・Consideration shall be given in design to prevent application of excessive thermal stress or piping stress on the joints.
・Piping design shall not allow accumulation of drain or scale at the flange sections.
・Consideration shall be given to prevent transmission of vibration to the joints.
・Although the likelihood of occurrence of cold flow in the VALFLON (PTFE) has been reduced by adopting flexible core materials, prolonged operation or heat cycles may cause bolts to be loosened. Therefore, these gaskets have to be used in locations permitting periodic checks of loose bolts and also allowing appropriate tightening force to be applied.
・When installing these gaskets onto titanium flanges, check to see if fluids to be handled contain chlorine ions, as even a trace amount of chlorine ions may cause crevice corrosion to develop on the titanium surface in contact with the gaskets. To prevent the occurrence of this crevice corrosion, titanium-palladium alloy is recommended.
・The inner diameter of VALQUA No.N7035 Series has a square shape, which serves to eliminate accumulation of liquids, if the gaskets are properly dimensioned to meet the flange inner diameter. For further details, please contact us, as gaskets can be dimensioned to meet the flange inner diameter.
・Even when resin, glass or hard rubber lined flanges comply with JIS flange standards, their inner diameter or the outer diameter in contact with the gaskets are different from the standards. It is therefore necessary to determine the gasket dimensions in conformity with the size of each flange. Further information in this regard is available on request. Also products are available on request, where the joint sheet has a core made of corrugated metallic sheet.

▼Notes to be observed before installation
・Check perpendicularity of the flange and the pipe.
・Shaft alignment of the mating flanges shall be ensured.
・Check for any deformation of flanges.
・When changing only gaskets for the existing equipment or at a piping joint, clean the connecting section and check for any damage, and repair, if required.
・Get off the rust at the flange surface, and repair any dents and dings.
・Pay attention not to give damage to gaskets during storage up to installation, or during installation work.

▼Notes to be observed before installation
・Install the gaskets in a clean environment so as to prevent entry of foreign matters between the gaskets and the flanges.
・If gasket paste is to be used, apply a minimum amount of "VALFLON Paste" uniformly. Also care shall be exercised after application of paste, to prevent adhesion of dust and the like.
・Flange bolts No.1 to 8 as shown on the figure shall be gradually tightened in this order at a time, and repeat this process in four to five steps, so as to finally ensure uniform tightening.
・As the VALFLON™ (PTFE) outer cover is slippery, crush may occur, if an excessive torque has been applied at the time of tightening or if it is not uniformly tightened. And this is particularly the case for smaller diameter ones, so that care should be exercised in tightening so as not to apply gasket stress exceeding 49.0 MPa.
・A small gap between flanges present at the time of gasket replacement would cause the VALFLON™ (PTFE) outer cover to touch the outside diameter of raised face or the flange inside, and fold over. Tightening in this condition may be a cause of leakage. In order to prevent such fold over of the VALFLON™ (PTFE) outer cover, the gasket-outer edge welded type (ODS type) is available. Further information in this regard is available on request.
・ At the time of tightening gaskets, air contained in the core material may be discharged, so that be careful not to mistake it for leakage when a leakage test is performed using soap water. Our recommendation is to check leakage sometime after tightening the gaskets.
・Insufficient tightening force may lead to permeation of soap water for airtightness test or rain water, causing the Non-Asbestos Felt Sheet to soften and squeezed out from the gaskets. In such a case, gasket stress decreases, which may result in leakage.
・At the time of load up or restarting, check for any loose bolts.
・If retightening of gaskets that have once experienced leakage failed in preventing leakage, replace them with new ones.

▼Notes to be observed in storage
・Store these joint sheets in a cool and dark place not subject to direct sunshine, fresh air or ozone.
・Storage selected shall be in a clean environment, free from dust as well as from high temperature & high humidity and corrosive atmosphere.
・If hanged on nails or the like, gaskets may suffer breakage or permanent deformation, so that, as far as practicable, they should be put in a can or wrapped in a polyethylene bag and stored in a paper box.
・Large sized gaskets shall be put between larger plates without rolling and placed horizontal for storage.
・If Felt Sheet got wet with aqueous liquids, its crush strength decreases. It is therefore necessary to keep it dry in a polyethylene bag, and also not to tighten when wet.