Speed control for compressors
First Claim
1. A dynamic speed limiter for a compressor, said compressor having a compressor element with a gas inlet and a gas outlet, a temperature sensor arranged to determine the outlet temperature in the gas outlet, a speed sensor arranged to determine the rotational speed of the compressor element, a motor driving the compressor with adjustable speed, and a speed control device for the motor, wherein said dynamic speed limiter comprises:
- a hysteresis module coupled to the speed control device and to the temperature and speed sensors,wherein the hysteresis module is configured with a hysteresis upper temperature limit, a hysteresis lower temperature limit, and a permitted maximum speed range including a minimum rotational speed and a maximum rotational speed,wherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to lower the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a high speed range appoximately at the compressor element maximum rotational speed, andwherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to lower the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a low speed range approximately at the compressor element minimum rotational speed; and
furtherwherein upon detecting from the temperature sensor that the specified hysteresis lower temperature limit is reached, the hysteresis module is configured to raise the rotational speed of the compressor element via the speed control device when the measured rotational speed is in an upper speed range approximate to the maximum compressor element rotational speed, andwherein the hysteresis module is configured to lower the rotational speed of the compressor element when the measured rotational speed is in a lower speed range approximately at the compressor element minimum rotational speed, and,wherein the hysteresis module is configured such that an increase of the rotational speed resulting from a hysteresis upper temperature limit being detected in the lower speed range of the compressor resulting in an increase of the operational pressure, results in an automatic idle condition of the compressor element.
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Accused Products
Abstract
Improvements to a compressor which consists in that, as soon as the measured outlet temperature (TO) reaches a certain hysteresis upper temperature limit (HMAX), the actual rotational speed of the compressor element is either lowered with a speed jump (DS) when the measured rotational speed is situated in the higher speed range close to the maximum rotational speed (SMAX), or is increased with a speed jump (DS) when the measured rotational speed is situated in the lower speed range close to the minimum rotational speed (SMIN).
40 Citations
20 Claims
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1. A dynamic speed limiter for a compressor, said compressor having a compressor element with a gas inlet and a gas outlet, a temperature sensor arranged to determine the outlet temperature in the gas outlet, a speed sensor arranged to determine the rotational speed of the compressor element, a motor driving the compressor with adjustable speed, and a speed control device for the motor, wherein said dynamic speed limiter comprises:
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a hysteresis module coupled to the speed control device and to the temperature and speed sensors, wherein the hysteresis module is configured with a hysteresis upper temperature limit, a hysteresis lower temperature limit, and a permitted maximum speed range including a minimum rotational speed and a maximum rotational speed, wherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to lower the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a high speed range appoximately at the compressor element maximum rotational speed, and wherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to lower the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a low speed range approximately at the compressor element minimum rotational speed; and
furtherwherein upon detecting from the temperature sensor that the specified hysteresis lower temperature limit is reached, the hysteresis module is configured to raise the rotational speed of the compressor element via the speed control device when the measured rotational speed is in an upper speed range approximate to the maximum compressor element rotational speed, and wherein the hysteresis module is configured to lower the rotational speed of the compressor element when the measured rotational speed is in a lower speed range approximately at the compressor element minimum rotational speed, and, wherein the hysteresis module is configured such that an increase of the rotational speed resulting from a hysteresis upper temperature limit being detected in the lower speed range of the compressor resulting in an increase of the operational pressure, results in an automatic idle condition of the compressor element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 16, 17, 18, 19, 20)
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12. A method for controlling a compressor having a dynamic speed limiter, said compressor having a compressor element with a gas inlet and a gas outlet, a temperature sensor to determine the outlet temperature in the gas outlet, a speed sensor to determine the rotational speed of the compressor element, a motor with adjustable speed driving the compressor, and a speed control device for the motor, comprising:
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providing the dynamic speed limiter with a hysteresis module, the hysteresis module being coupled to the speed control device and to the sensors for the outlet temperature and the rotational speed; detecting the gas outlet temperature of the compressor element; configuring the hysteresis module with a hysteresis upper temperature limit, a hysteresis lower temperature limit, and a permitted maximum speed range within a compressor element minimum rotational speed and a maximum rotational speed; when the gas outlet temperature reaches the specified hysteresis upper temperature limit, causing the hysteresis module to lower the rotational speed of the compressor element via the speed control device by a speed change when the measured rotational speed is in a high speed range approximately at the maximum rotational speed, when the gas outlet temperature reaches the specified hysteresis upper temperature limit, causing the hysteresis module to increase the rotational speed of the compressor element by a speed change when the measured rotational speed is in a low speed range approximately at the minimum rotational speed and further when the gas outlet temperature reaches the specified hysteresis lower temperature limit, causing the hysteresis module to raise the rotational speed of the compressor element via the speed control device when the measured rotational speed of the compressor element is in an upper speed range approximate to the maximum compressor element rotational speed, and lowering the rotational speed of the compressor element when the measured rotational speed is in a lower speed range approximately at the compressor element minimum rotational speed, and, when the increase of the rotational speed resulting from a hysteresis upper temperature limit being detected in the lower speed range of the compressor resulting in an increase of the operational pressure, results in an automatic idle condition of the compressor element.
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13. A dynamic speed limiter for a compressor, said compressor having a compressor element with a gas inlet and a gas outlet, a temperature sensor arranged to determine the outlet temperature in the gas outlet, a speed sensor arranged to determine the rotational speed of the compressor element, a motor driving the compressor with adjustable speed, and speed a control device for the motor, wherein said dynamic speed limiter comprises:
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a hysteresis module coupled to the speed control device and to the temperature and speed sensors, wherein the hysteresis module is configured with a hysteresis upper temperature limit, a hysteresis lower temperature limit, and a permitted maximum speed range including a minimum rotational speed and a maximum rotational speed, wherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to lower the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a high speed range approximately at the maximum rotational speed; wherein upon detecting from the temperature sensor that the hysteresis upper temperature limit of the outlet gas has been reached, the hysteresis module is configured to increase the rotational speed of the compressor element by a speed change via the speed control device when the measured rotational speed of the compressor element is in a low speed range approximately at the minimum rotational speed, and further wherein upon detecting from the temperature sensor that the specified hysteresis lower temperature limit is reached, the hysteresis module is configured to raise the rotational speed of the compressor element via the speed control device when the measured rotational speed is in an upper speed range approximate to the maximum compressor element rotational speed, and wherein the hysteresis module is configured to lower the rotational speed of the compressor element when the measured rotational speed is in a lower speed range approximately at the compressor element minimum rotational speed, and, wherein the hysteresis module is configured such that an increase of the rotational speed resulting from a hysteresis upper temperature limit being detected in the lower speed range of the compressor element resulting in an increase of the operational pressure, results in an automatic idle condition of the compressor element, and wherein the hysteresis module is further configured with a memory for storing gas outlet temperature curves representing the outlet temperature as a function of the rotational speed of the compressor element and the hysteresis upper and lower temperature limits, and a speed jump for the rotational speed that is effected when the hysteresis upper or the lower temperature limit is reached. - View Dependent Claims (14, 15)
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Specification