Abstract: A fitting assembly for forming a fluid-tight seal with an end of a stainless steel tube is provided with an adapter that is made of a material that is different from the material that the seal seat is made of. The material selected for the adapter is relatively less expensive than brass and the manufacturing method for making the adapter is relatively less expensive than that for making conventional adapters that are entirely made out of brass. According to an embodiment of the present invention, the adapter may be made of iron. According to an embodiment of the present invention, the seal seat may be made of a material that is softer than the material that the stainless steel tube is made of. According to another embodiment of the present invention, the seal seat may be made of a material that is harder than the material that the stainless steel tube is made of.

Abstract: A fitting assembly for forming a fluid-tight seal with an end of a stainless steel tube is provided with a seal seat that is composed of a material that is harder than the material that the stainless steel tube is composed of. The stainless steel tube may be gripped between a bushing and the seal seat to form a fluid-tight seal with the stainless steel tube. The fitting assembly may be tightened so that the stainless steel tube is deformed between the bushing and the seal seat of the fitting assembly.

Abstract: A fitting assembly for forming a fluid-tight seal with an end of a stainless steel tube is provided with an adapter that is composed of a material that is harder than the material that the stainless steel tube is composed of. The adapter may include an insert that is composed of a material that is harder than the material that the stainless steel tube is composed of. The stainless steel tube may be gripped between a bushing that is connected to a nut and an adapter to create the fluid-tight seal. The fitting assembly can be used to form a double-convolution compression in the stainless steel tube.

Abstract: A sealing device and method for sealing a length of tubing with a fitting is provided, where the sealing device includes at least one sealing surface formed with a plurality of ridges. The ridges include at least one end ridge and at least one internal ridge which are spaced apart by a predetermined distance, and formed with a desired geometry such as U-shaped, V-shaped, or various other shapes and with different sealing faces such as curved or flat. The ridges are spaced apart in a manner to maximize sealing pressure, and produce stress concentrations and localized deformations, in order to create a seal at lower torques or on stiffer tubing or tubing with at least one minor defect such as a dent or weld. The sealing device is particularly useful for sealing an end corrugation of tubing in a fitting used in gas and liquid piping systems.

Abstract: A sealing device and method for sealing a length of tubing with a fitting are provided, where the sealing device includes at least one sealing surface formed with a plurality of ridges. The sealing device is particularly useful for sealing at least an end corrugation of tubing in a fitting used in gas and liquid piping systems. The fitting is sized to maintain a generally circular shape of the end corrugation after the corrugation is collapsed between the ridged sealing surface and another sealing surface. In particular, an inner diameter of one or more components of the fitting can be sized such that the corrugated tubing will have a circular profile to provide an optimal seal.

Abstract: A fitting assembly for forming a fluid-tight seal with an end of a stainless steel tube is provided with an adapter that is composed of a material that is harder than the material that the stainless steel tube is composed of. The adapter may include an insert that is composed of a material that is harder than the material that the stainless steel tube is composed of. The stainless steel tube may be gripped between a bushing that is connected to a nut and an adapter to create the fluid-tight seal.