	US 12,031,537 B2
	Screw compressor with multi-layered coating of the rotor screws
Andreas Foerster, Coburg (DE); and Gerald Weih, Coburg (DE)
Assigned to KAESER KOMPRESSOREN SE, Coburg (DE)
Filed by KAESER KOMPRESSOREN SE, Coburg (DE)
Filed on Apr. 5, 2023, as Appl. No. 18/296,163.
Application 18/296,163 is a continuation of application No. 16/610,291, granted, now 11,649,823, previously published as PCT/EP2018/060673, filed on Apr. 26, 2018.
Claims priority of application No. 17169341 (EP), filed on May 3, 2017.
Prior Publication US 2023/0258180 A1, Aug. 17, 2023
Int. Cl. F04C 18/16 (2006.01); F01C 1/16 (2006.01); F04C 15/00 (2006.01); F04C 18/08 (2006.01); F04C 27/00 (2006.01)

CPC F04C 18/16 (2013.01) [F04C 18/084 (2013.01); F04C 27/009 (2013.01); F04C 2230/91 (2013.01); F04C 2240/20 (2013.01); F04C 2240/30 (2013.01); F04C 2240/50 (2013.01)]

20 Claims

1. A screw compressor comprising:

a compressor housing;

two rotor screws mounted axially parallel in the compressor housing, the two rotor screws meshing with each other in a compression space and synchronized with each other in their rotational movement; and

a drive in communication with the two rotor screws to rotate the rotor screws;

wherein each of the rotor screws comprises a single-part or multi-part base body with two end faces and a profiled surface extending therebetween and shaft ends projecting beyond the end faces, each of the shaft ends comprising a bearing seat and seal seats between the bearing seat and the end face;

wherein:

each profiled surface is coated with a first layer and the first layer is coated with a second layer, wherein the first layer and the second layer both comprise a thermoplastic synthetic material; and

each of the seal seats is coated with only the first layer; and wherein particles or pores supporting a running-in process are embedded in the second layer and the thermoplastic synthetic material defines a matrix for receiving the particles or for forming the pores, respectively.

6. A method for applying a multilayer coating to surfaces of a rotor screw of a screw compressor, the method comprising:

applying a first layer of a first thermoplastic synthetic material to a profiled surface of the rotor screw, the rotor screw comprising a single-part or multi-part base body with two end faces and the profiled surface extending therebetween and shaft ends projecting beyond the end faces, each of the shaft ends comprising a bearing seat and seal seats between the bearing seat and the end face;

coating the first layer of synthetic material on the profile surface with a second layer of a second thermoplastic synthetic material;

applying only the first layer of the first thermoplastic synthetic material to each of the seal seats of the rotor screw;

wherein particles or pores supporting a running-in process are embedded in the second layer and the second thermoplastic synthetic material defines a matrix for receiving the particles or for forming the pores, respectively.

11. A screw compressor comprising:

a compressor housing;

a drive in communication with the two rotor screws to rotate the rotor screws; wherein:

each of shaft ends comprising a bearing seat, each of the bearing seats is uncoated;

wherein particles or pores supporting a running-in process are embedded in the second layer and the thermoplastic synthetic material defines a matrix for receiving the particles or for forming the pores, respectively.

16. A method for applying a multilayer coating to surfaces of a rotor screw of a screw compressor, the method comprising:

coating the first layer of synthetic material on the profile surface with a second layer of a second thermoplastic synthetic material; and

maintaining each of the bearing seats uncoated by either the first layer or the second layer;