A pump assembly suitable for negative pressure wound therapy that includes an internal filter for preventing contamination in various components of the pump assembly, such as the pump unit. The internal filter is located in an isolated filter chamber, and inlet vacuum tubing that could contain fluids or bacteria are located inside a double containment sleeve to prevent contamination of components of the pump. The inlet vacuum tubing may be removed without opening the main pump housing and without contaminating the contents of the pump housing.
