Compact variable displacement index valve for screw compressor

Abstract

Accordingly, a screw compressor and a compact variable displacement index valve are provided. The compact variable displacement index valve includes a linear valve member positioned adjacent a compression chamber outlet end of a compression chamber of the screw compressor, an actuator structure coupled to the linear valve member and oriented to move the linear valve member radially along the compression chamber outlet end of the compression chamber to adjust a radial position of gas exiting the compression chamber, wherein the actuator structure is coupled to a gate of a screw valve of the screw compressor such that the actuator structure moves the linear valve based on a position of the screw valve of the screw compressor.

Description

Technical Field

[0001] This disclosure relates to a screw compressor, and more particularly to a screw compressor having a control mechanism capable of changing the compressor volume index. Background Technology

[0002] Screw-type gas compressors are known in the related art. In the related art, a screw compressor may include a compressor housing, and a motor (e.g., a permanent magnet rotor / stator motor) is used to drive one of two compression screws (e.g., a first compression screw). A second compression screw of the two compression screws may be mechanically coupled to the motor-driven compression screw. Thus, the second compression screw may be driven by the first compression screw. In the related art, gas is drawn into the compressor through an inlet, compressed between the two compression screws as they rotate, and output through an outlet located downstream of the gas inlet and the compression screw.

[0003] In some related technologies, a gas compressor may include a mechanical capacity control mechanism that provides one or more bypass ports or valve openings formed in the compressor housing or rotor shroud to allow gas to exit the housing to control or prevent overpressurization or compression along the length of the compression screw. In related technologies, one or more bypass ports or valve openings may be positioned adjacent to a helical valve that controls the opening and closing of the bypass ports or valve openings via a gate that rotates to open the bypass port and allows one or more bypass ports to communicate with a bypass chamber, thereby altering the compression length of the compressor.

[0004] However, in some related technologies, the adiabatic efficiency of a screw compressor equipped with a mechanical capacity control mechanism can be reduced by the amount of power used to recompress the gas supplied back to the compressor (under pressure) from the system. Furthermore, as the compressor capacity decreases via a variable capacity mechanism, the specific power (power / volume unit) increases.

[0005] In related technologies, if the compressor's Vi (volume index) is adjusted to a value suitable for the effective length determined by the capacity control mechanism, the specific power can be reduced. However, the variable Vi mechanism in related technologies is expensive, significantly increases the compressor's size, and requires a complex control system.

[0006] Furthermore, in related technologies, compressor manufacturers sometimes allow their compressors to produce gas pressures different from the gas pressure optimized for Vi, but doing so also leads to a reduction in adiabatic efficiency. Therefore, related technology systems may increase costs or reduce functionality. Summary of the Invention

[0007] Several aspects of this disclosure may include a compact variable volume index valve for a screw compressor. The compact variable volume index valve may include: a linear valve member positioned adjacent to the compression chamber outlet end of the screw compressor's compression chamber; and an actuator structure coupled to and oriented to move the linear valve member radially along the compression chamber outlet end of the compression chamber to regulate the radial position of gas exiting the compression chamber, wherein the actuator structure is coupled to a gate of a screw valve of the screw compressor such that the actuator structure moves the linear valve based on the position of the screw valve of the screw compressor.

[0008] Another aspect of this disclosure may include a screw compressor having a compressor housing, a helical valve, and a compact variable volume index valve. The compressor housing defines a compression chamber having a compression chamber outlet end and a plurality of bypass ports communicating with the compression chamber. The helical valve is positioned adjacent to the plurality of bypass ports communicating with the compression chamber. The helical valve includes a gate configured to selectively open and close one or more of the plurality of bypass ports based on rotational position. The compact variable volume index valve may include: a linear valve member positioned adjacent to the compression chamber outlet end of the compression chamber; and an actuator structure coupled to the linear valve member and oriented to radially move the linear valve member along the compression chamber outlet end of the compression chamber to regulate the radial position of gas exiting the compression chamber. The actuator structure is coupled to the gate of the helical valve of the screw compressor such that the actuator structure moves the linear valve based on the position of the helical valve of the screw compressor.

[0009] Another aspect of this disclosure may include an actuator structure having a toothed region disposed on a linear valve member and a gear engaging the toothed region of the linear valve member, wherein the gear is coupled to a shaft extending from the gate of a helical valve.

[0010] Another aspect of this disclosure may include a linear valve member having a semi-cylindrical shape.

[0011] Another aspect of this disclosure may include a linear valve member inserted into a radial bore formed in a compressor housing.

[0012] Another aspect of this disclosure may include a linear valve member inserted into a radial bore such that the valve member is offset from the centerline of the bore toward the outlet end of the compression chamber. Attached Figure Description

[0013] General architectures for implementing various features of this disclosure will now be described with reference to the accompanying drawings. The drawings and associated description are provided to illustrate exemplary embodiments of this disclosure, but not to limit its scope. Throughout the drawings, reference numerals are reused to indicate correspondences between reference elements.

[0014] Figure 1 A perspective view of a screw compressor according to an exemplary embodiment of the present disclosure is shown.

[0015] Figure 2 It shows according to Figure 1 The image shows a side view of a screw compressor according to an example embodiment of this disclosure.

[0016] Figure 3 It shows according to Figure 1 The image shows an end view of a screw compressor according to an example embodiment of this disclosure.

[0017] Figure 4 It shows according to Figure 1 The diagram shows a top view of a screw compressor according to an example embodiment of the present disclosure.

[0018] Figure 5 It shows along Figure 3 A cross-sectional view of a screw compressor taken from line V-V'.

[0019] Figure 6 It shows along Figure 3 A cross-sectional view of a screw compressor taken from line VI-VI'.

[0020] Figure 7 It shows along Figure 3 A cross-sectional view of a screw compressor taken from line VII-VII'.

[0021] Figure 8 It shows along Figure 4 A cross-sectional view of a screw compressor taken from line VIII-VIII'.

[0022] Figure 9 It shows along Figure 2 A cross-sectional view of a screw compressor taken from line IX-IX'.

[0023] Figure 10 It shows along Figure 2 A cross-sectional view of a screw compressor taken by line X-X'.

[0024] Figure 11 It shows Figure 8 An enlarged view of the compact variable Vi valve shown.

[0025] Figure 12 It shows Figure 10 An enlarged view of the compact variable Vi valve shown. Detailed Implementation

[0026] The following detailed description provides further details of the accompanying drawings and exemplary embodiments of this disclosure. For clarity, reference numerals and descriptions of redundant elements between the drawings are omitted. The terminology used throughout the description is provided by way of example and is not intended to be limiting. For example, the use of the term "automatic" may refer to fully automatic or semi-automatic embodiments involving user or operator control of certain aspects of the embodiments, depending on the implementation desired by one of ordinary skill in the art in practicing the embodiments of this disclosure. Furthermore, sequential terms such as "first," "second," "third," etc., may be used simply for labelling purposes in the description and claims and should not be limited to referring to actions or items appearing in the described sequence. Actions or items may be ordered into different sequences or may be performed in parallel or dynamically without departing from the scope of this disclosure.

[0027] As mentioned above, in some related technologies, the adiabatic efficiency of a screw compressor equipped with a mechanical capacity control mechanism can be reduced by the amount of power required to recompress the gas supplied to the compressor from the system. Furthermore, as the compressor capacity decreases via a variable capacity mechanism, the specific power increases. To attempt to address this issue, related technology systems can use a mechanism to adjust the compressor volumetric index (Vi) based on the effective length of the compressor determined by the capacity control mechanism. However, the variable Vi control mechanism of these related technologies is expensive, significantly increases the compressor's size, and requires a complex control system.

[0028] To address these issues, exemplary embodiments of this disclosure may include a CVVV (Compact Variable Vi Valve) that can reduce the size of the discharge port by raising the bottom edge of the discharge port (which determines Vi), thereby optimizing Vi for a capacity reduction resulting from a maximum capacity decrease determined by the mechanical capacity control system. In some exemplary embodiments, the CVVV may include a radial spool valve incorporated in the discharge surface of the rotor housing, such that as it moves downward, it effectively lowers the bottom edge of the port, thereby increasing the discharge port size and optimizing Vi for a new, higher capacity determined by the mechanical capacity control system.

[0029] As explained in this disclosure, the CVVV can be configured such that it can be applied to one or both sides of the exhaust port and actuated by a rack and pinion gear in contact with a pinion on a conventionally existing helical valve mechanism, or by a stepper motor, linear motor, cylinder, hydraulic cylinder, or similar device. In some example embodiments, using a single valve may provide cost-effectiveness, while two valves may provide better performance. Because the valve opens and closes radially from the exhaust port, it utilizes space that is normally not used, as this area serves as the usual path for the exhaust gas.

[0030] The variable nature of the CVVV also allows for cost-effective optimization of Vi to generate gas at various pressures. For this purpose, the CVVV is most likely to operate not via a rack and pinion mechanism, but via one of the various other methods listed above.

[0031] Figure 1 A perspective view of a screw compressor 100 with a spiral valve structure according to an exemplary embodiment of this application is shown. Furthermore, Figures 2-4 Side view, end view, and top view of a screw compressor 100 according to an exemplary embodiment of this application are shown respectively. As shown, the screw compressor 100 includes a compression chamber 3 surrounding the internal structure of the compressor. Figures 1-4 Not shown in the image. Figures 5-8 The compressor housing 10 (shown in the figure) may include one or more mounting brackets or feet 2 that support the screw compressor 100 and allow it to be secured to a floor or other support platform. For example, the feet 2 may allow the screw compressor 100 to be mounted on a portable support platform or trailer.

[0032] The housing 10 also defines a main airflow inlet 26 and a main airflow outlet 28. Arrows are provided to indicate the airflow through the screw compressor 100. Furthermore, the compressor housing 10 allows the drive shaft 15 to access the compressor's internal structure ( Figures 5-8 (As shown) leads to the area surrounding the compressor 100.

[0033] The drive shaft 15 can be used to mechanically connect the screw compressor 100 to a motor or engine to drive the screw compressor 100. The screw compressor 100 can be driven by an internal combustion engine (IC engine), such as a gasoline engine, a diesel engine, or any other type of engine that is obvious to those skilled in the art. The screw compressor 100 can also be driven by an electric motor, or by any type of machine that provides rotational power that is obvious to those skilled in the art.

[0034] Furthermore, actuator module 5 can be attached to compressor housing 10 and control the spiral valve structure located within compressor housing 10 (in Figures 5-8 (As shown in the diagram). As described below, actuator module 5 may include an electric motor coupled to a gearbox coupled to a helical valve. Furthermore, actuator module 5 may also include an integrated processor assembly that may include onboard control logic that manually controls actuator module 5, partially, semi-automatically, or entirely based on user input. Figures 6-10 As shown, actuator module 5 can also be used to control a compact variable Vi valve (CVVV).

[0035] Figures 5-8 A cross-sectional view of a screw compressor is shown. Specifically, Figures 5-7 They show the following along Figure 3 Cross-sectional views of the screw compressor taken along lines V-V', VI-VI', and VII-VII'. Furthermore, Figure 8 It shows along Figure 4 A cross-sectional view of a screw compressor taken from line VIII-VIII'.

[0036] The compressor housing 10 forms a compression chamber 3 that defines two adjacent holes 6 and 8, each of which, when the unit is assembled and in operation, includes a screw 7 or 9 of a twin-screw gas compressor 100. As shown, one of the screws 7 or 9 (also referred to as the drive screw) is mounted on a driven gear 210 and mechanically coupled to a shaft 15 via a drive gear 205. A motor or engine driving the screw gas compressor is coupled to the shaft 15. The other screw 7 (also referred to as the driven screw) is driven by the drive screw 9. The screws 7 and 9 may each be supported by a bearing assembly 225, such as roller bearings or any other type of bearing or bushing readily apparent to those skilled in the art.

[0037] Furthermore, in some example embodiments, one of these screws may have an internally threaded blade structure, and the other of these screws may have an externally threaded blade structure. In other words, one of these screws may be an internally threaded compression screw, and the other screw may be an externally threaded compression screw that engages with the internally threaded compression screw. For example, the drive screw 9 may be an externally threaded compression screw and the driven screw 7 may be an internally threaded compression screw. As will be apparent to those skilled in the art, the example embodiments of this application are not limited to this configuration, and some example embodiments may have alternative configurations (e.g., the drive screw 9 may be an internally threaded compression screw, and the driven screw 7 may be an externally threaded compression screw).

[0038] The end of the compressor housing 10 includes an outlet 28 in fluid communication with the inlet 26. Figures 1 to 4 (As shown in the figure). Airflow passages 215, 220 can connect each orifice 6, 8 to inlet 26 to allow gas to flow into each orifice 6, 8. Each orifice 6, 8 also includes one or more bypass ports collectively represented by numerals 12a-12e. The bypass ports 12a-12e shown are formed in orifice 6 associated with driven screw 7. In addition, similar bypass ports are formed in orifice 8 associated with drive screw 9, but are not shown herein. As shown, each bypass port 12a-12e is in fluid communication with bypass chamber 22, which contains a helical valve 20 rotatable along axis 24. The length of each orifice 6, 8 associated with bypass ports 12a-12e may be referred to as bypass window 245.

[0039] As described above, the compressor housing 10 has a gas inlet 26 and a gas outlet 28. Within the compressor housing, airflow passages 215 and 220 provide fluid communication between the inlet 26 and the compression chamber 3. When the screws 7 and 9 rotate within the corresponding holes 6 and 8 of the compression chamber 3, the gas is compressed within the compression chamber 3. The compression chamber 3 has a length extending between the compression chamber inlets 230 and 235 and the compression chamber outlet end 240. The compressed gas is then output through the gas outlet 28. The arrows indicate the airflow through the compression chamber 3.

[0040] like Figures 6-8 As shown, the spiral valve 20 includes a gate 335 that selectively blocks (closes) or opens bypass ports 12a-12e depending on the rotational position of the spiral valve 20. When the spiral valve 20 rotates to a point that allows one or more of the bypass ports 12a-12e to be in fluid communication with the spiral valve chamber 22, the effective compression volume of the compression chamber 3 may be reduced due to the shorter compression chamber length.

[0041] like Figure 6 As shown, bypass ports 12c-12e indicate flow, while bypass ports 12a and 12b do not indicate flow. With at least one bypass port 12c-12e open, the effective compression length of the compression chamber 3 is defined by the distance between the open bypass port closest to the compression chamber outlet end 240 and the compression chamber outlet end 240 itself.

[0042] When the effective compression volume decreases in this way, the torque decreases, which saves power, improves efficiency, and extends the life of the gas compressor components. However, as the compression capacity decreases, the adiabatic efficiency may be affected by the power required to recompress the gas returning from the system.

[0043] The screw valve 20 is coupled to an actuator module 5, which controls the rotation and position of the gate 335 of the screw valve 20. As shown, the actuator module 5 includes a motor 325 mechanically coupled to a gearbox 330. The gearbox 330 mechanically connects the motor 325 to the screw valve 20. Therefore, torque from the motor can be transmitted through the gearbox 330 to the gate 335 of the screw valve 20, thereby causing the gate 335 to rotate. The motor 325 may be an electric actuator motor, which provides precise control over the rotational speed and position of the screw valve.

[0044] Actuator module 5 can be attached to compressor housing 10 to control a spiral valve structure located within compressor housing 10. Furthermore, actuator module 5 may also include an integrated processor assembly that may include onboard control logic that controls motor 325 module automatically, semi-automatically, or entirely manually based on user input.

[0045] The spiral valve 20 can be rotated (or actuated) along its axis 24 from a fully open position (where all bypass ports are open) to a fully closed position (where all bypass ports are closed) and all points in between. Figures 6-8 In this diagram, the flow is indicated as if the helical valve 20 were rotated to a point that allows gas to bypass from the compression chamber 3 to the bypass chambers 215 and 220. Specifically, bypass ports 12c-12e allow gas to flow from the compression chamber 3 to the bypass chambers 215 and 220. The airflow is indicated by arrows.

[0046] Furthermore, exemplary embodiments of this disclosure also include a compact variable Vi valve 605 (CVVV), which in... Figures 6-8 Highlighted in an ellipse. CVVV 605 includes a valve member 620 mechanically coupled to a gear 615, which in turn is coupled to a rotating shaft 610 extending from the gate 335 of the spiral valve 20. CVVV 605 is discussed in more detail below.

[0047] Figure 9 and Figure 10 It shows along Figure 2 The cross-sectional view of the screw compressor taken by lines IX-IX' and X-X'. Figure 9 and Figure 10 The cross-sectional view provides an end view of the screw compressor, showing the main airflow outlet 28 and the compression chamber outlet 240. Figure 9 and Figure 10 The compact variable Vi valve (CVVV) 605 is also shown. Furthermore, in Figure 11 and Figure 12 An enlarged view of the CVVV 605 is shown in the image.

[0048] As described above, the CVVV 605 includes a valve member 620 mechanically coupled to a gear 615, which is coupled to a rotating shaft 610 extending from the gate of a helical valve. In some example embodiments, the valve member 620 is a linear member extending vertically upward into the compression chamber 3 near the compression chamber outlet end 240. Furthermore, when extending, the valve member 620 can extend radially across the face of the compression chamber outlet end to change the radial position of the gas exiting the compression chamber 3. The valve member 620 can have a cylindrical or semi-cylindrical shape. For example, the valve member 620 can have a semi-circular cross-section. Additionally, the valve member 620 can be positioned or inserted into a radial hole 625 formed in the compressor housing 10 such that the valve member 620 is offset from the centerline of the hole 625 toward the compression chamber outlet end 240. By offsetting within the hole 625, a good sealing operation against the compression chamber outlet end 240 can be achieved.

[0049] For example, valve member 620 can utilize the inherent sealing properties of a smaller cylinder that can slide within a slightly larger cylindrical bore that is open on a portion of its circumference on opposite sides, thus forming two sealing surfaces on each side of the cylinder. Pressure pushed in either direction seals the smaller cylinder against the larger cylindrical bore, sealing the passage and preventing flow around the valve. Furthermore, the centerline of valve member 620 is offset sufficiently from the discharge surface to provide sealing surfaces that resist pressure from either direction. Therefore, the seal of valve member 620 is included below the desired flow path to prevent any flow in that direction. Thus, valve member 620 can form a seal designed to allow a small amount of radial cylinder movement, enabling it to produce its radial sealing characteristics while providing axial sealing.

[0050] Valve member 620 is flat on one side to allow it to be positioned in the discharge face without creating voids in the discharge face that would reduce compressor efficiency. Because valve member 620 is partially located in the rotor bore, valve plug material can be used to fill any voids in the surface of the rotor bore that would cause gas to leak through the rotor apex to a lower pressure thread. Valve plug material can also be used to maintain valve orientation so as not to interfere with rotor movement. The cavity surrounding the actuated side of the valve can be sealed or opened to release pressure. If opened to release pressure, this will make it easier to manufacture and assemble.

[0051] In some example embodiments, valve member 620 may have an actuator structure including a toothed region 630 that engages with gear 615 to move linearly upward based on rotation of gear 615 when gear 615 is coupled to shaft 610 extending from gate 335 of helical valve 20. This arrangement allows the position of valve member 620 to be controlled by actuator module 5 that controls rotation of gate 335. Furthermore, the position of valve member 620 can be coordinated with gate 335 such that valve member 620 is optimally positioned for each orientation of gate 335 that controls the length of compression chamber 3.

[0052] Example embodiments of CVVV 605 are not limited to actuator structures for valve members having toothed regions 630 of gears 615 meshing with a gate 335 of a helical valve 20. In other example embodiments, CVVV 605 may include actuator structures characterized by linear actuators (such as hydraulic cylinders, pneumatic pistons, or stepper motors) coupled to the gate 335.

[0053] In some example implementations, the CVVV 605 can be implemented with one or two valve members. For example, one valve member can be positioned on the male side of the compression chamber outlet 240, and another valve member can be positioned on the female side of the compression chamber outlet 240. However, if the valve member 620 used is large enough to allow the required flow, only one valve member is needed on one side. Because the externally and internally threaded blades 305 / 310 / 315 / 320 mesh and connect to the same compression chamber, a single-valve configuration can be acceptable.

[0054] While the invention is susceptible to various modifications and alternatives, specific embodiments thereof have been illustrated by way of example in the accompanying drawings and described in detail herein. However, it should be understood that the description of particular embodiments herein is not intended to limit the invention to the specific forms disclosed. Furthermore, the exemplary embodiments are not limited to industrial or fixed locations; portable configurations can be achieved by mounting the screw compressor 100 on a vehicle, trailer, or other portable structure.

[0055] The foregoing detailed description has illustrated various exemplary embodiments of the apparatus and / or process using figures, schematic diagrams, and examples. Within the scope of such figures, schematic diagrams, and examples, which encompass one or more functions and / or operations, each function and / or operation within such figures or examples can be implemented individually and / or collectively by a wide range of structures. While certain exemplary embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of protection. In fact, the novel methods and apparatus described herein can be embodied in a variety of other forms. Furthermore, different omissions, substitutions, and changes to the form of the apparatus and systems described herein can be made without departing from the spirit of protection. The appended claims and their equivalents are intended to cover forms or modifications falling within the scope and spirit of protection.

Claims

1. A compact variable volumetric index valve for a screw compressor, the screw compressor having a compressor housing defining a compression chamber, the compact variable volumetric index valve comprising: A linear valve component, the linear valve component being positioned adjacent to the compression chamber outlet end; as well as An actuator structure is coupled to the linear valve member and oriented to allow the linear valve member to move radially along the compression chamber outlet end of the compression chamber, thereby adjusting the radial position of the gas leaving the compression chamber. The actuator structure is connected to the gate of the screw valve of the screw compressor, such that the actuator structure moves the linear valve component based on the position of the screw valve of the screw compressor.

2. The compact variable volume index valve according to claim 1, wherein, The actuator structure includes: A toothed region, the toothed region being disposed on the linear valve member; and A gear that engages the toothed region of the linear valve member, wherein the gear is coupled to a shaft extending from the gate of the helical valve.

3. The compact variable volume index valve according to claim 1, wherein, The linear valve component has a semi-cylindrical shape.

4. The compact variable volume index valve according to claim 1, wherein, The linear valve component is inserted into a radial hole formed in the compressor housing.

5. The compact variable volume index valve according to claim 4, wherein, The linear valve component is inserted into the radial hole such that the linear valve component is offset from the centerline of the radial hole toward the outlet end of the compression chamber.

6. A screw compressor, comprising: A compressor housing defining a compression chamber having a compression chamber outlet and a plurality of bypass ports communicating with the compression chamber; A helical valve positioned adjacent to the plurality of bypass ports communicating with the compression chamber, the helical valve including a gate configured to selectively open and close one or more of the plurality of bypass ports based on rotational position; as well as Compact variable volume index valve, including: A linear valve component, the linear valve component being positioned adjacent to the outlet end of the compression chamber; and An actuator structure is coupled to the linear valve member and oriented to allow the linear valve member to move radially along the compression chamber outlet end of the compression chamber, thereby adjusting the radial position of the gas leaving the compression chamber. The actuator structure is connected to the gate of the screw valve of the screw compressor, such that the actuator structure moves the linear valve member based on the position of the screw valve of the screw compressor.

7. The screw compressor according to claim 6, wherein, The actuator structure includes: A toothed region, the toothed region being disposed on the linear valve member; and A gear that engages the toothed region of the linear valve member, wherein the gear is coupled to a shaft extending from the gate of the helical valve.

8. The screw compressor according to claim 6, wherein, The linear valve component has a semi-cylindrical shape.

9. The screw compressor according to claim 6, wherein, The linear valve component is inserted into a radial hole formed in the compressor housing.

10. The screw compressor according to claim 9, wherein, The linear valve component is inserted into the radial hole such that the linear valve component is offset from the centerline of the radial hole toward the outlet end of the compression chamber.

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