Impregnation and Sealing Equipment Information
Impregnation equipment and sealing equipment uses vacuum, pressure, vacuum and pressure, and/or wicking-action techniques to drive resins or coating materials into parts and seal pores. There are many different types of impregnation and sealing equipment. Dry vacuum pressure (DVP) equipment and vacuum-only impregnation (VOI) equipment uses a vacuum pressure chamber to coat the tiny pores on a part’s surface. Vacuum pressure impregnation (VPI) equipment also uses a vacuum pressure chamber, but forces liquid penetrants into pores with pressure cycles up to 100 psi. Internal impregnation equipment places an impregnant inside a metal casting and applies hydraulic pressure, forcing the liquid through the leak paths in the casting wall. Wet vacuum (VW) impregnation equipment submerges parts in a liquid-penetrant bath and evacuates the air above the bath. Part surfaces are rinsed with water before heat is used to cure the material in the pores. In trickle impregnation systems, surface-tension effects allow resins to be wicked or soaked up by the internal porosity of a part (like a sponge soaking up water). Other types of impregnation and sealing equipment are also available.
Most impregnation equipment and sealing equipment consists of a vacuum/pressure or vacuum-only chamber, vacuum pump assembly, impregnant reservoir, reservoir cooling assembly, agitator, transfer piping, and operator interface. Some impregnation systems include a false bottom, load plate, liner, or rotor shaft extension. Others provide a strainer or filter for the transfer line, a chart recorder, and a capacitance meter. Impregnation and sealing systems with integral software and/or data storage devices are also available. In terms of performance, powdered metal impregnation equipment and metal casting impregnation equipment usually carries specifications such as cubic feet of parts per hour. In general, wet vacuum (WV) impregnation systems provide higher outputs than dry vacuum pressure (DVP) systems. VPI equipment may carry additional specifications.
Applications and Approvals
There are many different applications and approvals for impregnation equipment and sealing equipment. Many DVP, VOI, and VPI systems are used to seal electronic components against corrosion, or to protect automotive parts such as power steering pumps against the ingress of gases or liquids. To meet U.S. military specifications (MIL-SPEC), impregnation equipment and sealing equipment must be designed for use with low-viscosity liquids that do not contain inert solvents or filterable solid materials in suspension. These impregnant properties enable capillary action to penetrate the tiniest openings and deepest cavities.