US 11,953,006 B2 · Screw compressor and control method therefor

Abstract

A screw compressor (100), comprising a screw rotor (110) and a spool valve (120). The screw rotor (110) comprises a suction head end (111) and an exhaust tail end (112). Gas is sucked in from the suction head end (111) and compressed gas is discharged from the exhaust tail end (112). The spool valve (120) comprises a working side (125) for sealing a compression chamber of the screw rotor (110). The working side (125) comprises a spool valve head end (121) and a spool valve tail end (122) and can do a reciprocating motion along the axis direction of the screw rotor (110). When the spool valve (120) moves to a suction capacity adjusting position (240), the spool valve head end (121) is located at the inner side of the suction head end (111) of the screw rotor (110), and a suction capacity adjusting distance (D2) is formed between the spool valve head end (121) and the suction head end (111) so that the suction capacity of the screw compressor is adjusted. The suction capacity of the screw compressor (100) can be adjusted by means of the spool valve (120), so that the problem of motor temperature and exhaust gas temperature limits of conventional variable frequency screw sets is effectively solved and the operational range and the load regulation ability of the screw compressor are expanded.

Claims12

Dependent claims

A screw compressor comprising:

a screw rotor comprising a suction head end and an exhaust tail end, wherein the screw rotor is configured to suck in gas from the suction head end and discharge compressed gas from the exhaust tail end;
and
a spool valve comprising a working side for sealing a compression chamber of the screw rotor, wherein the working side comprises a spool valve head end and a spool valve tail end, the spool valve head end and the spool valve tail end are arranged in a common direction as the suction head end and the exhaust tail end of the screw rotor along an axis direction of the screw rotor, and the spool valve is configured for reciprocating motion along the axis direction of the screw rotor;
wherein the spool valve is configured to move to a suction capacity adjusting position, wherein, in the suction capacity adjusting position, the spool valve head end is located at an inner side of the suction head end of the screw rotor, and a suction capacity adjusting distance is formed between the spool valve head end and the suction head end, wherein the suction capacity adjusting distance is adjustable to adjust a suction capacity of the screw compressor without changing a speed of the screw rotor.

1 more element

A control method for operating a screw compressor, comprising:

a) setting a working frequency parameter (F) and a working internal volume ratio parameter (Vi) of the screw compressor based on a target load, wherein the working frequency parameter (F) corresponds to a predetermined working suction capacity (R);
b) determining whether the working frequency parameter (F) is lower than a working frequency threshold (Ft), wherein the working frequency threshold (Ft) corresponds to a threshold suction capacity (Rt);
and
c) adjusting a position of a spool valve based on the working frequency parameter al and the working internal volume ratio parameter wherein:
c1) when the working frequency parameter (F) is not lower than the working frequency threshold (Ft),
(i) the working frequency parameter (F) is set as a working frequency of the screw compressor to adjust a speed of a screw rotor of the screw compressor and to adjust a suction capacity of the screw compressor toward the predetermined working suction capacity (R), and a displacement (L1) of the spool valve moving to an internal volume ratio adjusting position corresponding to the working internal volume ratio parameter is determined based on the set working internal volume ratio parameter (Vi), and
(ii) the spool valve is moved to the internal volume ratio adjusting position based on the displacement (L1), and, when the spool valve is in the internal volume ratio adjusting position, a spool valve head end of the spool valve is located at an outer side of a suction head end of the screw rotor of the screw compressor or is aligned with the suction head end, such that the spool valve shields a section of the screw rotor extending from the suction head end to an exhaust tail end of the screw rotor, and
c2) when the working frequency parameter (F) is lower than the working frequency threshold (Ft),
(i) the working frequency threshold (Ft) is set as the working frequency of the screw compressor to adjust the speed of the screw rotor, and a displacement (L2) of the spool valve moving to a suction capacity adjusting position corresponding to the predetermined working suction capacity (R) is determined based on the working internal volume ratio parameter (Vi), and
(ii) the spool valve is moved to the suction capacity adjusting position based on the displacement (L2), and, when the spool valve is in the suction capacity adjusting position, the spool valve head end is located at an inner side of the suction head end of the screw rotor, and a suction capacity adjusting distance (D2) is formed between the spool valve head end and the suction head end, such that the threshold suction capacity (Rt) corresponding to the working frequency threshold (Ft) is adjusted to the predetermined working suction capacity (R).

7 more elements

Dependencies are inferred from the claim text.

Screw compressor and control method therefor

Life of this patent

Screw compressor and control method therefor

Life of this patent

Abstract

Claims12