A pneumatic plug gauge has been developed in the context of the invention. This plug gauge comprises a first measuring channel which can be connected to a pressure medium source and opens into a first outlet for the pressure medium, which outlet can be directed to a surface of the workpiece to be tested. According to the invention, this plug gauge is designed to determine the tilt angle between a section on the surface thereof and a region opposite this section on the surface of the workpiece by virtue of the first outlet being arranged at one end of the section and at least one second outlet being provided, which second outlet is arranged at the other end of the section. It has been recognized that the admittedly high precision of pneumatic length measurements can be converted in a particularly advantageous manner to high precision of the angle measurement in this manner. The tilt angle can be measured at least with an accuracy of less than one tenth of a degree. At the same time, the measurement is fast enough for 100% control in mass production. The plug gauge is the central element in the measuring system and in the method, to which the invention likewise relates.

A pneumatic plug gauge has been developed in the context of the invention. This plug gauge comprises a first measuring channel which can be connected to a pressure medium source and opens into a first outlet for the pressure medium, which outlet can be directed to a surface of the workpiece to be tested. According to the invention, this plug gauge is designed to determine the tilt angle between a section on the surface thereof and a region opposite this section on the surface of the workpiece by virtue of the first outlet being arranged at one end of the section and at least one second outlet being provided, which second outlet is arranged at the other end of the section. It has been recognized that the admittedly high precision of pneumatic length measurements can be converted in a particularly advantageous manner to high precision of the angle measurement in this manner. The tilt angle can be measured at least with an accuracy of less than one tenth of a degree. At the same time, the measurement is fast enough for 100% control in mass production. The plug gauge is the central element in the measuring system and in the method, to which the invention likewise relates.

A pneumatic plug gauge has been developed in the context of the invention. This plug gauge comprises a first measuring channel which can be connected to a pressure medium source and opens into a first outlet for the pressure medium, which outlet can be directed to a surface of the workpiece to be tested. According to the invention, this plug gauge is designed to determine the tilt angle between a section on the surface thereof and a region opposite this section on the surface of the workpiece by virtue of the first outlet being arranged at one end of the section and at least one second outlet being provided, which second outlet is arranged at the other end of the section. It has been recognized that the admittedly high precision of pneumatic length measurements can be converted in a particularly advantageous manner to high precision of the angle measurement in this manner. The tilt angle can be measured at least with an accuracy of less than one tenth of a degree. At the same time, the measurement is fast enough for 100% control in mass production. The plug gauge is the central element in the measuring system and in the method, to which the invention likewise relates.

A pneumatic plug gauge has been developed in the context of the invention. This plug gauge comprises a first measuring channel which can be connected to a pressure medium source and opens into a first outlet for the pressure medium, which outlet can be directed to a surface of the workpiece to be tested. According to the invention, this plug gauge is designed to determine the tilt angle between a section on the surface thereof and a region opposite this section on the surface of the workpiece by virtue of the first outlet being arranged at one end of the section and at least one second outlet being provided, which second outlet is arranged at the other end of the section. It has been recognized that the admittedly high precision of pneumatic length measurements can be converted in a particularly advantageous manner to high precision of the angle measurement in this manner. The tilt angle can be measured at least with an accuracy of less than one tenth of a degree. At the same time, the measurement is fast enough for 100% control in mass production. The plug gauge is the central element in the measuring system and in the method, to which the invention likewise relates.

A probe for determining the swirl angle of the exhaust gasses of a turbine engine, has an elongate body with a fastener, the elongate body having a tip at its proximal end and a head at its distal end, the elongate body having at least two passageways extending from the tip to the head, each passageway having an aperture at the tip and a port at the head which is connectable to a pressure sensor.

A probe for determining the swirl angle of the exhaust gasses of a turbine engine, has an elongate body with a fastener, the elongate body having a tip at its proximal end and a head at its distal end, the elongate body having at least two passageways extending from the tip to the head, each passageway having an aperture at the tip and a port at the head which is connectable to a pressure sensor.

Various embodiments include approaches for determining a top-dead-center (TDC) of a reciprocating compressor. In some cases, an apparatus includes: a pressure transducer configured to measure pressure fluctuations inside a compressor cylinder and convert the pressure fluctuations into an asynchronous waveform; and at least one computing device operably connected with the pressure transducer, the at least one computing device configured to: extract a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform; remove data representing invalid piston angles from the data set to form a refined data set; determine an average piston angle for the single revolution from the refined data set; and adjust the refined data set to identify a top-dead-center (TDC) position of the piston within the compressor cylinder.

Various embodiments include approaches for determining a top-dead-center (TDC) of a reciprocating compressor. In some cases, an apparatus includes: a pressure transducer configured to measure pressure fluctuations inside a compressor cylinder and convert the pressure fluctuations into an asynchronous waveform; and at least one computing device operably connected with the pressure transducer, the at least one computing device configured to: extract a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform; remove data representing invalid piston angles from the data set to form a refined data set; determine an average piston angle for the single revolution from the refined data set; and adjust the refined data set to identify a top-dead-center (TDC) position of the piston within the compressor cylinder.

An illumination apparatus includes: a light source including an LED and a lens; an illuminated body; and a cover, wherein: the light source is arranged inside the cover; the light from the light source passes between the edge of the cover and the illuminated body; the front edge of the cover defines the illumination range of the light from the light source with respect to the illuminated body; and the light transmittance of such portion of the lens as is near to the illuminated body is higher than that of the remaining portions.

Sensors for measuring rotation about an axis are disclosed, along with methods of making and using the same. The sensors can utilize ionic liquids and electrodes that provide a unique electrical signal at each angle of rotation about an axis. The sensors can include a solid structure with a channel that circumnavigates the axis, electrodes disposed within the channel, and an ionic liquid positioned within the channel.