A heating installation or cooling installation mixing device has a valve housing (14) including a first flow path from a first connection (A-B) to a second connection (A), and a second flow path from the first connection (A-B) to a third connection (B). A movable valve element (24), arranged inside the valve housing (14) in the flow paths, is configured to vary a ratio of cross sections of the flow paths. A valve element drive (36) is arranged on the valve housing (14) and includes an internal control device (38) for movement control of the drive (36) and includes a first communication interface (44) for external control device (40) communication and a second communication interface (46). An internal sensor (48, 50) is arranged in or on the valve housing (14) and is connected to the first communication interface (44) for transmitting a sensor signal to the external control device (40).

An electromagnetic valve as a fluid device is provided with a valve seat and a valve body midway of a flow path where a liquid flows, and closes the valve with the valve body pressed onto the valve seat and opens the valve by causing a gap between the valve seat and the valve body. The electromagnetic valve includes, as electrodes for measuring a degree of electrical conductivity between a liquid on an upstream side and a liquid on a downstream side of the valve seat and the valve body in the flow path, a first electrode electrically conductive to the liquid on the upstream side and a second electrode electrically conductive to the liquid on the downstream side. By using the first and second electrodes, detection of liquid leakage can be easily performed.

An electromagnetic valve as a fluid device is provided with a valve seat and a valve body midway of a flow path where a liquid flows, and closes the valve with the valve body pressed onto the valve seat and opens the valve by causing a gap between the valve seat and the valve body. The electromagnetic valve includes, as electrodes for measuring a degree of electrical conductivity between a liquid on an upstream side and a liquid on a downstream side of the valve seat and the valve body in the flow path, a first electrode electrically conductive to the liquid on the upstream side and a second electrode electrically conductive to the liquid on the downstream side. By using the first and second electrodes, detection of liquid leakage can be easily performed.

The invention relates to a system and a method for injecting liquid odorant into a natural gas pipe, the system comprising: a tank containing the odorant in liquid form; a high-pressure pump connected to the tank; a common injection manifold fed with liquid odorant by the high-pressure pump; a plurality of odorant injectors fed with liquid odorant under pressure by the common injection manifold for the purpose of injecting the odorant into the gas pipe so as to cause it to be atomized in the gas pipe; and an electronic injection computer for controlling the injectors and the high-pressure pump.

A system is configured to generate a pressurized flow of gas comprised of a first gas having a partial pressure that varies in a predetermined manner. This may be used, for example, to simulate a previous and/or theoretical respiratory gas flow that was produced (or could have been produced) by a subject. The system is configured to deliver the pressurized flow of gas to a testing system configured to measure the partial pressure the first gas in flows of gas. This may provide an opportunity to determine the response of individual testing systems to various clinical circumstances.

A system is provided to control fluid flow in a wastewater treatment system through wastewater level manipulation. The wastewater treatment system may include a wastewater treatment plant connected to a plurality of pump stations by a main. Each of the plurality of pump stations may include a wet well with a pump therein. The system may include a central server in communication with a sensor to sense a level of wastewater within the wet well. The pump may be automatically moved to an on position when the level of the wastewater in the wet well is at or above a first level and may be automatically moved to an off position when the level of the wastewater in the respective wet well is at or below a pump cutoff level. The central server may systematically manipulate the first level to selectively set the level of wastewater within the wet well.