Abstract: An assembly having a first compressor train and a second compressor train for compressing a process fluid, wherein the first compressor train has a first drive and a first compressor, wherein the second compressor train has a second drive and a second compressor, wherein the first compressor train is not mechanically coupled to rotating parts of the second compressor train for transmission of torque, wherein the two compressors of the different compressor trains are directly connected to each other fluidically by a connecting fluid line such that the first compressor is arranged upstream of the second compressor. The first compressor compresses at a pressure ratio between 1.1 and 1.6 before the process fluid is fed to the second compressor.

Abstract: An assembly having a first compressor train and a second compressor train for compressing a process fluid, wherein the first compressor train has a first drive and a first compressor, wherein the second compressor train has a second drive and a second compressor, wherein the first compressor train is not mechanically coupled to rotating parts of the second compressor train for transmission of torque, wherein the two compressors of the different compressor trains are directly connected to each other fluidically by a connecting fluid line such that the first compressor is arranged upstream of the second compressor. The first compressor compresses at a pressure ratio between 1.1 and 1.6 before the process fluid is fed to the second compressor.

Abstract: A coated tool consisting of a cermet body and a refining layer thereon. The refining layer is a wear resistant layer of (Ti, Me) N, wherein Me is at least one metal which forms a stable oxide at a temperature above 700.degree. C.

Abstract: The hard coating includes mainly (Al,Cr).sub.2 0.sub.3 mixed crystals and a chrome content higher than 5 at %. The coating is deposited at a temperature lower than 900.degree. C., preferably lower than 500.degree. C. The hard coating is deposited by a CVD or PVD process.

Abstract: The hard coating includes mainly (Al,Cr).sub.2 O.sub.3 crystals and a chrome content higher than 5 at % wherein the (Al, Cr).sub.2 O.sub.3 is a single crystal. The coating is deposited at a temperature lower than 90.degree. C., preferably lower than 500.degree. C. The hard coating is deposited by a CVD or PVD process.

Abstract: A coated tool or instrument has a wear-resistant hard coating (7) which is preferably titanium nitride for working organic material which is disposed on a separating layer (9) applied on a basic body (3). The separating layer (9) comprises a ceramic electrically non-conducting material. Such a material is preferably an oxide, nitride or oxynitride of silicon. The separating layer (9) protects the basic body (3) of the tool or instrument of e.g. a non-corrosion resistant steel. During the coating of the basic body (3) with the ceramic material, a pulsating dc voltage is applied to the basic body (3) or its holders. The pulse height is changed during the vapor deposition from high negative values to low negative values.

Abstract: Coated highly wear-resistant tools have an Me.sup.1.sub.1-x (.alpha..sub.2 Me.sup.2 * .alpha..sub.3 Me.sup.3 * . . . .alpha..sub.n Me.sup.n).sub.x N.sub.u C.sub.v O.sub.w coating, wherein Me.sup.1 is a metal of the chemical group IVb of the periodic system, and Me.sup.2, Me.sup.3, . . . , Me.sup.n are other metals. The values u+v+w=1 and the Me concentration changes at least once continuously over the layer thickness to .alpha..sub.2 Me.sup.2 * .alpha..sub.3 Me.sup.3, . . . .alpha..sub.n Me.sup.n. The value for x is preferably between 0.1 and 0.7, the values for v and/or w can be approximately zero or w<0.3, and the further metal Me.sup.2, Me.sup.3, . . . , Me.sup.n is another metal of the chemical group IVb of the periodic system and/or vanadium and/or preferably aluminum. In working tasks with the tools according to the invention as compared to known tools, a significantly increased service life is obtained.