[Mechanical Equipment Technology Edition] Daily Question 20171023: Energy regulation device for screw compressors
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This post was last edited by YORK Industrial Refrigeration on 2017-10-26 at 09:51. Starting from now, in order to enhance communication among users, a 【Daily Question】 campaign has been launched on the Mechanical Equipment Technology forum. We hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth points for active participation, 10-15 wealth points for correct answers. This question is valid for two days; no scoring will be given if more than two days pass. As shown in the figure below, this depicts the process of energy regulation in the compressor. Please describe in words the operating condition of the compressor. It is easy to see from the figure that this compressor has an adjustable volume ratio. The slide valve determines the capacity, while the slider determines the volume. Figure 1: Both the slider and the slide valve are in their initial positions; at this point the compressor is at zero load (as indicated), with an actual capacity of around 15 percent. Figure 2: The slide valve is in motion, indicating full load. At this point, the capacity is at full load; the York spool is also at full load, and the volume ratio is 2.2. Figure 3: Slider movement – The conditions for slider movement are: the spool being at full load and under-compression. When the slider is moved, the content volume ratio can be adjusted freely within the range of 2.2–5.0. In this diagram, the slider is moved to its maximum position and makes full contact with the working area of the screw! The volume ratio at this time is 5.0 ================================ High-quality promotions: Mobile equipment---York screw compressors – maintenance procedures http://bbs.hcbbs.com/thread-1806833-1-1.html Mobile equipment---York Quinton control centers – upgrades http://bbs.hcbbs.com/thread-1804837-1-1.html Mobile equipment---GEA Grasso screw compressors – major repairs http://bbs.hcbbs.com/thread-1800467-1-1.html Mobile equipment---British HOWDEN screw compressors – disassembly and maintenance http://bbs.hcbbs.com/thread-1832529-1-1.html Mobile equipment---Japanese Maekawa MYCOM screw compressors – disassembly and maintenance http://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1786445
Slide valve regulation: This method of adjustment is used in screw-type chiller units. The procedure involves installing a regulating slide valve on the compressor housing, which becomes part of the compressor structure. It is located at the intersection of the two inner circles on the high-pressure side of the engine, and can slide back and forth in a direction parallel to the cylinder axis. The basic principle of slide valve regulation is that, as the slide valve moves, the elemental volume between the teeth of the male and female rotors in the screw compressor changes. During the period before the contact line on the tooth surfaces shifts from the suction side to the discharge side, the return hole of the slide valve remains connected to the suction port, allowing some gas to flow back to the suction port. In this way, by changing the effective working length of the rotors, energy regulation is achieved. Regulation using plug valves: Another method for adjusting the compressor energy in screw-type chillers is to utilize multiple plug valves for this purpose. The opening and closing of the plug valve is achieved by controlling the inflow and outflow of oil in the hydraulic pump through a solenoid valve. The plug valve can only achieve stepwise regulation of the gas flow rate, with load levels of 70%, 50%, 25%, etc. This type of regulation method is often seen in small screw chillers and compact screw chillers.
The upper image shows the inhalation process, the middle image shows the compression process, and the lower image shows the expulsion process.
Slide valve regulation: This method of adjustment is used in screw-type chiller units. The procedure involves installing a regulating slide valve on the compressor housing, which becomes part of the compressor structure. It is located at the intersection of the two inner circles on the high-pressure side of the engine, and can slide back and forth in a direction parallel to the cylinder axis. The basic principle of slide valve regulation is that, as the slide valve moves, the elemental volume between the teeth of the male and female rotors in the screw compressor changes. During the period before the contact line on the tooth surfaces shifts from the suction side to the discharge side, the return hole of the slide valve remains connected to the suction port, allowing some gas to flow back to the suction port. In this way, by changing the effective working length of the rotors, energy regulation is achieved. Regulation using plug valves: Another method for adjusting the compressor energy in screw-type chillers is to utilize multiple plug valves for this purpose. The opening and closing of the plug valve is achieved by controlling the inflow and outflow of oil in the hydraulic pump through a solenoid valve. The plug valve can only achieve stepwise regulation of the gas flow rate, with load levels of 70%, 50%, 25%, etc. This type of regulation method is often seen in small screw chillers and compact screw chillers.
Slide valve regulation: This method of adjustment is used in screw-type chiller units. The procedure involves installing a regulating slide valve on the compressor housing, which becomes part of the compressor structure. It is located at the intersection of the two inner circles on the high-pressure side of the engine, and can slide back and forth in a direction parallel to the cylinder axis. The basic principle of slide valve regulation is that, as the slide valve moves, the elemental volume between the teeth of the male and female rotors in the screw compressor changes. During the period before the contact line on the tooth surfaces shifts from the suction side to the discharge side, the return hole of the slide valve remains connected to the suction port, allowing some gas to flow back to the suction port. In this way, by changing the effective working length of the rotors, energy regulation is achieved. Regulation using plug valves: Another method for adjusting the compressor energy in screw-type chillers is to utilize multiple plug valves for this purpose. The opening and closing of the plug valve is achieved by controlling the inflow and outflow of oil in the hydraulic pump through a solenoid valve. The plug valve can only achieve stepwise regulation of the gas flow rate, with load levels of 70%, 50%, 25%, etc. This type of regulation method is often seen in small screw chillers and compact screw chillers.
The basic principle of slide valve regulation is that, as the slide valve moves, the elemental volume between the teeth of the male and female rotors in the screw compressor changes. During the period when the contact line on the tooth surfaces moves from the suction end toward the discharge end, the return hole of the slide valve remains connected to the suction port, allowing some gas to flow back to the suction port. In this way, by changing the effective working length of the rotors, energy regulation is achieved. In the first image, the slide valve is at the far right, resulting in the lowest energy level. In the second image, the slide valve is at the far left, resulting in the highest energy level. In the third image, the slide valve is in the middle, giving an energy level of 50%
First image: slider at 2.2, spool at 0/100. Second image: slider at 2.2, spool at 100/100. Third image: slider at 5.0, spool at 100/100
First image: Yabi under unloading conditions with a small volume. Second image: Small volume ratio. Third image: Large volume ratio
Using a slide valve to adjust the energy ratio of a screw machine is a common method employed in screw refrigeration compressors.