Setting and maintaining proper pre-charge air pressure in a diaphragm or bladder-type expansion tank of any fluid system is essential for safe and efficient operation of that system. In usual practice, pre-charge air pressure checks are done by emptying the system of fluid and connecting an analog air gauge to the air input of the expansion tank. In this invention a pressure sensor that is permanently coupled to the fluid volume of the expansion tank is used to also evaluate the pre-charge air pressure in the tank. By employing a single sensor for both fluid and pre-charge air pressure evaluation, the problem of inconsistent calibration between fluid sensing and air pre-charge measuring devices is eliminated. Using the same permanently installed sensor for every test or adjustment in a given system eliminates the problem of variations in calibration between different sensors or gauges used at different testing times.

A method is provided for detecting leaks in a disposable medical fluid cassette that includes a base and a flexible membrane attached to the base in such a way that the base and the flexible membrane cooperate to at least partially form a fluid passageway. The method includes applying a first force to the flexible membrane, measuring a first physical property of a system that includes the medical fluid cassette a medical fluid pumping machine, removing the first force from the flexible membrane, applying a second force to the flexible membrane, measuring a second physical property of the system, and determining whether the medical fluid cassette leaks based on a comparison of the first physical property and the second physical property.

The invention relates to a film chamber for receiving a test object to be tested for the presence of a leak, including at least two film layers and at least two frame elements, each of which has a sealing surface so that the two frame elements lie against each other in a gas-tight manner in order to hermetically seal the film chamber. Each of the two film layers has at least one retaining profile in a wall region, and each of the two frame elements has at least one retaining groove in the frame element sealing surface in order to receive a retaining profile such that the two film layers are held between the two frame elements substantially by a formfitting connection.

A method for calibrating a test chamber, which encloses an interior volume (20), is designed as a film chamber (12) comprising at least one flexible wall region (14, 16), and is connected in a gas-conducting way to a pressure sensor (30), to a vacuum pump (26), and via a calibration valve (34) to a calibration chamber (36) enclosing a calibration volume (37), comprising the following steps: evacuating the film chamber (12); measuring the pressure difference inside of the film chamber (12); after the evacuation has been completed, connecting the calibration volume (37) in a gas-conducting manner to the interior volume (20) of the film chamber (12) while measuring the pressure change, wherein the pressure in the calibration chamber (36) is greater than the pressure in the film chamber (12) before the connection to the film chamber (12). A corresponding device is likewise disclosed.

A method for testing the sealing tightness of a specimen, containing a gas, in a film chamber made from flexible material. The film chamber is evacuated by a vacuum pump and the gas flow flowing out of the film chamber and generated by the vacuum pump is measured during the evacuation and is examined with respect to a possible leak of the specimen.

A test system and a corresponding method for testing the seal of a glove which is installed in a port of an isolator, including a test disc which can be connected in a hermetically sealed fashion to the port. The glove and test disc define a sealed glove volume which can be placed under excess pressure. The test disc has a pressure-measuring device with a microprocessor and a memory for recording and storing a pressure profile in the glove volume and a data interface. The glove and port have identification elements which are read by a reading device of the test disc and information concerning the pressure profile along with the identities of the glove and port are transmitted wirelessly to an evaluation unit which estimates and records a residual period of use of the glove. A plurality of gloves in ports can be tested simultaneously.

A method is provided for detecting leaks in a disposable medical fluid cassette that includes a base and a flexible membrane attached to the base in such a way that the base and the flexible membrane cooperate to at least partially form a fluid passageway. The method includes applying a first force to the flexible membrane, measuring a first physical property of a system that includes the medical fluid cassette a medical fluid pumping machine, removing the first force from the flexible membrane, applying a second force to the flexible membrane, measuring a second physical property of the system, and determining whether the medical fluid cassette leaks based on a comparison of the first physical property and the second physical property.

A method for performing a leak-tightness test on a test object (16) in a foil chamber (10) which has at least one flexible wall region (12, 14), having the steps: using a gas or gas constituent contained in the test object as test gas for the leak-tightness test, introducing the test object into the foil chamber, evacuating the foil chamber to a pressure lower than the test gas pressure within the test object and than atmospheric pressure, introducing a carrier gas into the foil chamber into the region outside the test object, and measuring the test gas concentration of the gas mixture that forms in the foil chamber in the region outside the test object.

The invention relates to a simplified method for detecting leaks on a non-rigid test specimen, comprising the steps of: introducing the test specimen into a film chamber, lowering the pressure in the film chamber outside of said test specimen, and detecting a leak in the test specimen on the basis of a spatial change in the film of said film chamber.

A film chamber for receiving a test object which is to be tested with respect to the presence of a leak, wherein the film chamber has walls enclosing a film chamber volume, said walls having at least one flexible wall region, wherein a measuring volume adjoining the flexible wall region is arranged on the side of the flexible wall region which is situated opposite the film chamber volume and is hermetically separated from the film chamber volume.