An oil circuit for lubrication and cooling of an oil-free compressor with an oil reservoir and a rotary oil pump to drive oil to the compressor element and/or the motor via an oil pipe. The rotary oil pump has a rotor mounted on a rotation shaft, and is driven by the motor of the compressor. The oil circuit is provided with a bypass pipe and a pressure-actuated bypass valve which guide a portion of the oil back to the oil reservoir without this portion of the oil passing through the compressor element and/or the motor during its way back to the oil reservoir. The oil circuit is further provided with an oil cooler in the bypass pipe. The bypass valve is in the oil pipe.

Device for controlling the oil temperature of an oil-injected compressor installation (1) with a compressor element (2) that is provided with a gas inlet (3) and an outlet (5) for compressed gas that is connected to an oil separator (8) that is connected by means of an injection pipe (12) to the aforementioned compressor element (2), and whereby a cooler (17) is affixed in a part (19) of the injection pipe (12) that can be bypassed by means of a bypass pipe (18), characterised in that the device (20) is provided with an extra pipe (21) that is intended to be connected in parallel with the bypass pipe (18) and the cooler (17), and in which an energy recovery system (22) can be connected, and that the device (20) is provided with flow distribution means (23) through the cooler (17), the bypass pipe (18) and the extra pipe (21), and a controller (28) for controlling these temperature (T.sub.out) control means at the aforementioned outlet (5) of the compressor element (2).

A screw machine, in particular screw compressor, includes a machine housing, screw rotors forming a rotor pair which is mounted in the machine housing, an oil supply system via which bearings and seals of the screw rotors can be supplied with oil for lubricating and/or cooling, wherein the oil supply system has an oil supply and oil feeds, wherein the oil supply system includes a pressure sensor, which detects a pressure in the oil discharge or oil return or a pressure difference between the pressure in the oil discharge or oil return and a pressure in the oil feeds, the oil supply system furthermore includes a control device, which open-loop or closed-loop controls the pressure in the oil feed or the pressure difference dependent on the measurement signal of the pressure sensor.

A sensor casing includes a lower case and an upper case that is fixed to an upper part of the lower case. A valve body includes an upper body including an accommodation space in which a sensor casing is disposed and a lower body in which an oil passage is formed. The upper body includes a stopper that prevents downward movement of the oil pressure sensor along a central axis. The sensor casing includes an engagement portion that engages with the stopper to retain the oil pressure sensor in the accommodation space.

A compressor may include a crankshaft, first and second cylinder housings, first and second rotors, a divider plate, and first and second valves. The crankshaft includes first and second eccentric portions. The cylinder housings define cylindrical recesses. The rotors are disposed within respective cylindrical recesses and engage respective eccentric portions of the crankshaft. The first rotor and the first cylindrical recess define a first compression chamber therebetween. The second rotor and the second cylindrical recess define a second compression chamber therebetween. The divider plate may be disposed between the cylinder housings and may include first and second fluid openings in communication with the first and second compression chambers. The valves may be moveable relative to the divider plate between a first position allowing fluid flow through the fluid openings and a second position restricting fluid flow through the fluid openings.

A liquid-cooled rotary compressor includes a compressor main body having a compression chamber formed by a fixed wall and a rotating wall and compressing gas, and a liquid injection path for injecting a coolant into the compression chamber, and adjusts a discharge flow rate by changing a rotational speed of the rotating wall. The compressor includes a liquid amount adjusting unit that adjusts an amount of the coolant supplied from the liquid injection path to the compressor main body according to a change in the rotational speed of the rotating wall, and a compressed gas supply path that supplies compressed gas to a downstream side of the liquid amount adjusting unit in the liquid injection path. The compressed gas is supplied from the compressed gas supply path to the liquid injection path according to the amount of the coolant supplied to the compressor main body.

The invention relates to a method for controlling the water supply of a water-injected compressor, into the cooling water circuit of which is injected demineralized and non-demineralized water as fresh water. The method according to the invention is characterized in that the fresh water supplied is a mixture of demineralized and non-demineralized water, and the proportions of the demineralized and non-demineralized water in the fresh water are dependent on the conductivity of the demineralized and non-demineralized water. The invention also relates to a water-injected gas compressor that may be operated with such a method.

An oil-injected screw air compressor includes a first stage compression chamber, an air buffering chamber coupled to the first stage compression chamber, a second stage compression chamber coupled to the air buffering chamber, a first oil cooling device for cooling lubricating oil for the first stage compression chamber and the air buffering chamber, a second oil cooling device for cooling lubricating oil for the second stage compression chamber and the first oil cooling device, a plurality sensors respectively located at the first stage compression chamber outlet and the second stage compression chamber outlet, and a control unit respectively and dynamically controlling the first oil cooling device and the second oil cooling device according to preset pressure and temperature data measured by the sensors or pressure and temperature data measured by the sensors, and temperature data and humidity data of an environment.

An oil-injected screw air compressor includes a first stage compression chamber, an air buffering chamber coupled to the first stage compression chamber, a second stage compression chamber coupled to the air buffering chamber, an oil cooling device for cooling lubricating oil for the first stage compression chamber, the air buffering chamber and the second stage compression chamber, a plurality sensors respectively located at outlets of the first stage compression chamber, the air buffering chamber and the second stage compression chamber, and a control unit respectively and dynamically controlling flow rates of the lubricating oil entering into the first stage compression chamber, the air buffering chamber and the second stage compression chamber according to temperature and pressure data measured by the sensors.

A two-stage oil-injected screw air compressor includes an integrated compression casing, and the integrated compression casing further includes a first stage compression chamber, an intermediate cooling channel, and a second stage compression chamber parallel stacked in the integrated compression casing. A straightforward oil injector aims at the intermediate cooling channel to spray lubricating oil into the intermediate cooling channel.