A wound therapy system comprising: a wound dressing; a pressure sensor; a container having an internal chamber; a vacuum source pneumatically associated with the internal chamber of the container; and a tube set comprising a first tube and a second tube positioned inside a lumen of the first tube, wherein a space between the first tube and the second tube forms a fluid channel, and wherein a lumen of the second tube forms a sensor channel in the tube set; wherein the wound dressing is pneumatically associated with the internal chamber of the container by the fluid channel of the tube set; wherein the wound dressing is pneumatically associated with the pressure sensor by the sensor channel of the tube set; and wherein a crushing force required to occlude the fluid channel is greater than a crushing force required to occlude a fluid channel of a comparison tube set that does not include a second tube positioned inside a lumen of the first tube; characterised by the wound therapy system further comprising a restrictor pneumatically associated with the wound dressing by the sensor channel of the patient tube, wherein the restrictor has a hole that is configured to allow air to leak into the wound therapy system, wherein the restrictor comprises: a body having a first port and a second port; a cap coupled to the first port of the body, the cap having a hole; and a porous material positioned between the cap and the first port of the body; wherein the restrictor is configured to allow air to enter through the hole in the cap and pass through the porous material before entering the first port of the body. a wound dressing; a pressure sensor; a container having an internal chamber; a vacuum source pneumatically associated with the internal chamber of the container; and a tube set comprising a first tube and a second tube positioned inside a lumen of the first tube, wherein a space between the first tube and the second tube forms a fluid channel, and wherein a lumen of the second tube forms a sensor channel in the tube set; wherein the wound dressing is pneumatically associated with the internal chamber of the container by the fluid channel of the tube set; wherein the wound dressing is pneumatically associated with the pressure sensor by the sensor channel of the tube set; and wherein a crushing force required to occlude the fluid channel is greater than a crushing force required to occlude a fluid channel of a comparison tube set that does not include a second tube positioned inside a lumen of the first tube; characterised by the wound therapy system further comprising a restrictor pneumatically associated with the wound dressing by the sensor channel of the patient tube, wherein the restrictor has a hole that is configured to allow air to leak into the wound therapy system, wherein the restrictor comprises: a body having a first port and a second port; a cap coupled to the first port of the body, the cap having a hole; and a porous material positioned between the cap and the first port of the body; a body having a first port and a second port; a cap coupled to the first port of the body, the cap having a hole; and a porous material positioned between the cap and the first port of the body; wherein the restrictor is configured to allow air to enter through the hole in the cap and pass through the porous material before entering the first port of the body.