Air compressor

• US 10,995,756 B2
• Filed: 03/24/2017
• Issued: 05/04/2021
• Est. Priority Date: 06/28/2016
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kotani, Masanao, Tsuchiya, Takeshi, Kawai, Ryoji, Chiba, Kotaro, Kanada, Minako, Sekiya, Sachio
• Primary Examiner(s): Comley, Alexander B
• Application Number:
  US16/312,382
• Publication Number:
  US 20190242382A1
• Time in Patent Office: 1,502 Days
• Field of Search: 418 84, 418 85, 418 87, 184 616, 184 622
• CPC Class Codes: F04B 39/02 Lubrication of machines or engines in general F01M
• CPC Class Codes: F04B 39/0207 with lubrication control systems
• CPC Class Codes: F04B 39/0238 with oil distribution channels
• CPC Class Codes: F04B 39/0284 Constructional details, e.g. reservoirs in the casing swash-plate compressors F04B27/0878, F04B27/109
• CPC Class Codes: F04B 39/16 Filtration; Moisture separation
• CPC Class Codes: F04C 18/12 of other than internal-axis type
• CPC Class Codes: F04C 18/16 with helical teeth, e.g. chevron-shaped, screw type for non-parallel axes of movement F04C18/48
• CPC Class Codes: F04C 2210/221 Air
• CPC Class Codes: F04C 2270/052 angular
• CPC Class Codes: F04C 2270/19 Temperature
• CPC Class Codes: F04C 29/021 Control systems for the circulation of the lubricant
• CPC Class Codes: F04C 29/026 Lubricant separation
• CPC Class Codes: F04C 29/042 by injecting a fluid injection of fluid for sealing, cooling or lubrication F04C29/0007

Abstract

Provided is an air compressor which helps to attain a proper discharge air temperature and which is superior in energy saving property. There are provided an air line connecting an air compressor, an oil separator, and an after cooler; an oil circulation line connecting the air compressor, the oil separator, and an oil cooler; a bearing oil supply line connecting one end of an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor to a bearing oil supply portion of the air compressor; an intermediate portion oil supply line connecting the other end of the intermediate branching portion to an intermediate oil supply portion of the air compressor; a branching line supplying oil to the bearing oil supply portion and the intermediate oil supply portion; a blower sending air to the oil cooler and the after cooler; a bypass line connecting one end of a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler to the downstream side of the oil cooler of the bearing oil supply line; and a control valve controlling the inflow amount of the lubricating oil to the bypass line.

Claims

1. An air compressor unit comprising:

an air compressor;

an oil separator separating compressed air discharged from the air compressor and a lubricating oil from each other;

an oil cooler cooling the lubricating oil discharged from the oil separator;

an after cooler cooling discharged air from the air compressor;

an air line effecting connection such that the discharged air successively flows through the air compressor, the oil separator, and the after cooler;

an oil circulation line effecting connection such that the lubricating oil successively circulates through the air compressor, the oil separator, and the oil cooler;

an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor;

a bearing oil supply line connecting one end of the intermediate branching portion to a bearing oil supply portion of the air compressor;

an intermediate oil supply line connecting another end of the intermediate branching portion to an intermediate oil supply portion of the air compressor;

a branching line supplying the lubricating oil to the bearing oil supply portion and the intermediate oil supply portion;

a blower sending cooling air to the oil cooler and the after cooler,

wherein the air compressor unit further includes

a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler,

a bypass line connecting one end of the bypass branching portion to the bearing oil supply line at a location downstream of the oil cooler, and

a control valve controlling an inflow amount of the lubricating oil to the bypass line; and

a first detector that detects an air temperature outside the air compressor unit, a second detector that detects a sucked-in air temperature of the air compressor, a third detector that detects an air temperature inside the oil separator, and a fourth detector that detects oil supply temperatures of the lubricating oil at the bearing oil supply portion and the intermediate oil supply portion,

wherein, based on the temperatures detected by the detectors, at least one of a revolution speed of the blower, a revolution speed of the air compressor, and an opening degree of the control valve is controlled.

2. An air compressor unit comprising:

an air compressor;

an oil separator separating compressed air discharged from the air compressor and a lubricating oil from each other;

an oil cooler cooling the lubricating oil discharged from the oil separator;

an after cooler cooling discharged air from the air compressor;

an air line effecting connection such that the discharged air successively flows through the air compressor, the oil separator, and the after cooler;

an oil circulation line effecting connection such that the lubricating oil successively circulates through the air compressor, the oil separator, and the oil cooler;

an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor;

a bearing oil supply line connecting one end of the intermediate branching portion to a bearing oil supply portion of the air compressor;

an intermediate oil supply line connecting another end of the intermediate branching portion to an intermediate oil supply portion of the air compressor;

a branching line supplying the lubricating oil to the bearing oil supply portion and the intermediate oil supply portion; and

a blower sending cooling air to the oil cooler and the after cooler,

wherein the air compressor unit further includes

a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler,

a bypass line connecting one end of the bypass branching portion to the bearing oil supply line at a location downstream of the oil cooler, and

a control valve controlling an inflow amount of the lubricating oil to the bypass line,

wherein an auxiliary oil cooler is provided on an upstream side of the bypass line, and

the auxiliary oil cooler is situated on a downstream side of the oil cooler with respect to an air sending direction of the blower.

3. An air compressor unit comprising:

an air compressor;

an oil separator separating compressed air discharged from the air compressor and a lubricating oil from each other;

an oil cooler cooling the lubricating oil discharged from the oil separator;

an after cooler cooling discharged air from the air compressor;

an air line effecting connection such that the discharged air successively flows through the air compressor, the oil separator, and the after cooler;

an oil circulation line effecting connection such that the lubricating oil successively circulates through the air compressor, the oil separator, and the oil cooler;

an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor;

a bearing oil supply line connecting one end of the intermediate branching portion to a bearing oil supply portion of the air compressor;

an intermediate oil supply line connecting another end of the intermediate branching portion to an intermediate oil supply portion of the air compressor;

a branching line supplying the lubricating oil to the bearing oil supply portion and the intermediate oil supply portion;

a blower sending cooling air to the oil cooler and the after cooler,

wherein the air compressor unit further includes

a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler,

a bypass line connecting one end of the bypass branching portion to the bearing oil supply line at a location downstream of the oil cooler, and

a control valve controlling an inflow amount of the lubricating oil to the bypass line;

wherein the intermediate oil supply portion comprises a plurality of intermediate oil supply portions provided along the air compressor in a direction in which a pressure inside the air compressor increases;

a spray branching portion branching the intermediate portion oil supply line with respect to the plurality of intermediate oil supply portions; and

lubricating oil temperature detection means detecting a temperature of the lubricating oil at the spray branching portion,

wherein a temperature of the lubricating oil is controlled based on a detection temperature of the lubricating oil temperature detection means and a temperature of a compressed air on a side of the plurality of intermediate oil supply portions at a lower pressure.