Abstract: A system for testing systems which are in turn used to test the leaktightness of a hollow body is suggested. Instead of the hollow body, a test body (2) is placed in the system which generates a defined pressure increase in a measuring chamber (4) within a pre-determined time span. This defined pressure increase corresponds exactly to the pressure increase generated by a hollow body with a small amount of leakage, wherein the hollow body can still just be regarded as leaktight. The test body can be configured as a glass capillary which extends in a sealing manner between two chambers with different air pressure. Alternatively, the test body can comprise a material which can accept a defined amount of moisture from the ambient atmosphere during storage. A vacuum formed around the test body causes moisture to be withdrawn from the test body and at least partially evaporated in the vacuum, which again leads to an increase in pressure in the chamber.

Abstract: A test assembly includes a valve and a piston received in a casing. The valve includes a main passage and a flexible seal film is mounted to an end of the valve. The seal film seals the main passage and has two apertures. A radial passage is defined through the valve and communicates with the main passage. A sub-passage is located in parallel with the main passage and communicates with the radial passage and one of the apertures of the seal film. A control member is rotatably and radially inserted in the valve and has a first path radially through the shank of the control member and communicates with the main passage. A second path is defined in half way of the shank and communicates with the first passage.

Abstract: Apparatus 10 for condition monitoring the integrity of a rivet 12 joint holding together sheets 14 and 16 of a structure 18 includes a substantially fluid impervious pad 20 for covering the heads of the rivets 12 and an adjacent surface 24 of the structure 18. The pad 20 has a first surface 26 for placement over the rivets 12 and the surface 24. An inner portion of the surface 26 is formed or otherwise configured to define a fluid flow region 28 between the pad 20 and the rivets 12/surface 24 across which fluid can flow. The region 28 is coupled to a constant vacuum source 30 via a conduit 32 and a series coupled high fluid flow impedance 34. A transducer 38 and display 44 coupled in parallel across the impedance 34 provides an indication of change in differential pressure across the high impedance which in turn provides an indication of the presence or development of a flaw in the rivets joint.

Abstract: A method for generating indicators relating to the condition of lubricating oil in an internal combustion engine. A set of variables relating to operation of the internal combustion engine serve as proxy variables for brake mean effective pressure developed by the internal combustion engine. Operation of an engine is monitored to develop values for the proxy variables. Soot being added to the lubricating oil from the developed values and accumulated to provide an estimate of total soot in the lubricating oil. Lubricating oil temperature is periodically monitored and a history of the lubricating oil temperature measurements is kept to allow generation therefrom of an estimate of shear of the lubricating oil. Accumulated estimate of soot is kept as a distance remaining until the lubricating oil becomes unsuitable for continued use in the internal combustion engine. Similarly, estimated shear is expressed as a distance until the lubricating oil is to be replaced.

Abstract: A flowmeter for accurately measuring the flowrate of fluids in high pressure chromatography systems. The flowmeter is a porous bed of a material, the porous bed having a porosity in the range of about 0.1 to 0.6 and a pore size in the range of about 50 nm to 1 &mgr;m, disposed between a high pressure pumping means and a chromatography column. The flowmeter is provided with pressure measuring means at both the inlet and outlet of the porous bed for measuring the pressure drop through the porous bed. This flowmeter system provides not only the ability to measure accurately flowrates in the range of &mgr;L/min to nL/min but also to provide a signal that can be used for a servo loop or feedback control system for high pressure pumping systems.

Abstract: The invention relates to a method for measuring lengths pneumatically. According to the invention, the medium used for measuring is conducted through a front nozzle and a measuring nozzle, onto a deflection plate. The distance of the deflection plate from the measuring nozzle is determined from the change in pressure p2 occurring between the front nozzle and the measuring nozzle. The pressure p1 in front of the front nozzle is also measured and the length value resulting from the pressure measurement between the front nozzle and the measuring nozzle is corrected according to said pressure p1. This ensures that a high level of measuring accuracy can be achieved using a small quantity of compressed air.