Patent Application
20250180001
Compressors are used in various industrial applications. Other than air, some gas compressors can process fluid that may possess properties such as flammability, toxicity, corrosiveness, or environmentally hazardous. Current fluid compressor designs introduce several disadvantages, such as venting to atmosphere and reduced efficiency. One issue is the oscillation of fluid flow in the crankcase vent line, which changes direction twice with each crankshaft revolution, leading to rapid oscillations. These oscillations cause frictional heat to build up in the vent line, heating the fluid. When this heated fluid enters the inlet of a compressor, its reduced density results in a lower mass flow rate due to the compressor's fixed volume intake per stroke, which reduces efficiency. Additionally, the increase in inlet temperature can lead to higher discharge temperatures, negatively impacting the lifespan of key components in the compressor. Furthermore, the constant movement of fluid in the ventilation line may utilize additional power, reducing the compressor's mechanical efficiency, which can lead to higher energy consumption and potentially may require additional fluid aftercooling downstream of the compressor.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key factors or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
In one implementation, a compressor assembly may comprise a crankcase with a suction pipe fluidly coupled with the interior of the crankcase. A crankcase suction valve may be located between the fluid connection of interior of the crankcase and suction pipe, wherein the crankcase suction valve is configured to mitigate (e.g., prevent) backflow of fluid from the interior of the crankcase into the suction pipe. A first piston may comprise a one-way suction valve that allows fluid to flow from the crankcase through the first piston and into a first cylinder. A one-way discharge valve may be connected to a head of the first cylinder, facilitating the expulsion of compressed fluid out of the first cylinder to the cylinder head.
To the accomplishment of the foregoing and related ends, the following description and annexed drawings set forth certain illustrative aspects and implementations. These are indicative of but a few of the various ways in which one or more aspects may be employed. Other aspects, advantages and novel features of the disclosure will become apparent from the following detailed description when considered in conjunction with the annexed drawings.
What is disclosed herein may take physical form in certain parts and arrangement of parts, and will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
The word “exemplary” is used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Further, at least one of A and B and/or the like generally means A or B or both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims may generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter.
Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure.
In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.”
The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are generally used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to facilitate describing the claimed subject matter.
In many compressor designs, the volume of the crankcase (i.e., the volume below or between the piston(s)) changes as the piston(s) move in the cylinder(s). For example, in a simple single cylinder vertical compressor the crankcase volume decreases on a suction stroke, as the piston is drawn out of (e.g., moves downward) in the cylinder. In this example, the crankcase volume increases on a discharge stroke, as the piston is drawn into (e.g., moves upward) in the cylinder. In the case of an air compressor, this may not present an issue as the crankcase is typically vented to the atmosphere and ambient air freely moves in and out of the crankcase, through the vent, as the volume of the crankcase changes. However, in the case of a gas compressor, the crankcase contains process gas, which is often flammable, toxic, corrosive, environmentally unfriendly, etc., and which cannot be routinely vented to the atmosphere. In such gas compressors, the crankcase is typically vented back into the compressor's suction line side, which draws back into the cylinder to be processed.
However, the gas flows back and forth through the crankcase vent line it changes directions twice with each revolution of the crankshaft. This results in a rapid oscillation in flow direction in the vent line. For example, with a compressor speed of 1800 RPM, the flow direction in the vent line must change directions 60 times per second. This method has multiple disadvantages. First, the rapid flow oscillations cause frictional heat to build up in the vent line. As such, the temperature of the gas in the vent line increases, and much of that hot gas is ingested into the compressor's inlet. Hot inlet gas is less dense than cooler inlet gas. Because the compressor ingests a fixed volume of gas on each inlet stroke, the compressor's mass flow rate has to be lower with a hot (less dense) gas compared to the flow rate with a cooler (denser) gas.
Secondly, a higher inlet gas temperature will produce a higher discharge temperature. Higher discharge temperatures can shorten the life of the compressor's primary performance and wear components such as the piston rings and valves. Third, there is a parasitic power load resulting from the rapid gas flow oscillations. That is, moving the gas back and forth rapidly in the vent line requires additional power input to the compressor. This increase in power use will reduce the compressor's mechanical efficiency. Thus, more power is consumed by the compressor which results in higher energy consumption by the power supply (electric motor, engine, etc.). Fourth, higher discharge temperatures can create the need for additional gas after cooling downstream of the compressor, thus adding additional complexity, components, cost, power consumption and more.
An innovation in compressor design is provided, which improves the overall performance of the compressor, by mitigating some of the shortcomings of current and prior compressors. In one aspect, the compressor's suction or inlet line can connect, not to the compressor's head, as is common, but rather to its crankcase. In some implementations, a crankcase suction valve (e.g., a one-way check valve) can be located at the connection point of the suction line to the crankcase. The crankcase suction valve can mitigate back flow from the crankcase into the suction pipe when the crankcase volume is decreasing, merely allowing flow from the suction line to the crankcase. Additional suction valves can be located in the compressor's piston(s) that merely allow gas flow from the crankcase, through the piston, and into the cylinder(s).
In some implementations, as illustrated in
As illustrated in
Further, as illustrated, the first piston 112 can comprise a first piston port 130 that fluidly couples the crankcase chamber 104 with the first cylinder 108; and the second piston 114 can comprise a second piston port 132 that fluidly couples the crankcase chamber 104 with the second cylinder 110. A first piston valve 134 (e.g., a one-way valve) can be disposed at the first piston port 130 and can be configured to merely allow fluid flow from the crankcase chamber 104 to the first cylinder 108. A second piston valve 136 (e.g., a one-way valve) can be disposed at the second piston port 132 and can be configured to merely allow fluid flow from the crankcase chamber 104 to the second cylinder 110. A suction or inlet port 146 can be disposed between, and fluidly couple, the suction or inlet line 106 and the crankcase chamber 104. A first suction valve (e.g., a one-way valve) can be disposed at the suction or inlet port 136 and can be configured to merely allow flow from the suction line 106 to the crankcase chamber 104.
As an illustrative example, as further illustrated in
During a discharge stroke, as illustrated in
Some implementations of the compressor assembly 100 may utilize reed valves for the respective port valves (148, 142, 134, 136, 144), but other implementations may utilize various types of flow implements including but not limited to butterfly valves, ball valves, check valves, diaphragm valves, globe valves, gate valves or other similar mechanisms. Each of these valve types offers unique characteristics and advantages, making them suitable for specific functions within the compressor assembly 100. In some embodiments, the operational fluids and gases may include but are not limited to methane, ethane, propane, butane, isobutane, pentane, pentanes plus, and mixtures thereof may be used as the operating fluid.
During operation, the first suction valve 148 closes and prevents fluid returning to the suction line 106. Fluid in the crankcase 102 may then be forced through the respective ports 130, 132 of the pistons 112, 114 (although in some implementation there may be just one piston and one piston port utilized), via respective piston valves 134, 136, and into the cylinders 116, 118. In a single stage compressor implementation, during the suction stroke the volume of crankcase chamber 104 may decrease, causing the crankcase suction valve 148 to close as the piston 112, 114 move radially inward. This, in turn increases the volume in the cylinders 108, 110. Thereafter, fluid is forced from the crankcase chamber 104 into the cylinders 108, 110 via the piston valves 134, 136. The first suction valve 148 also functions to prevent backward flow into the crankcase suction line 106, which could cause problems feeding the compressor otherwise.
In other embodiments, the innovative piston and valve design may be implemented in a two-stage compressor, as illustrated in
A crankcase inlet suction port 2060 is disposed at the interface of the suction line 1010 and the crankcase chamber 1020. The crankcase inlet suction port 2060 is arranged to supply fluid into the crankcase 1020. The first stage cylinder 2040 is connected to, and fluidly coupled with, a first cylinder head 2080 such that fluid can flow from the first stage cylinder 2040, through the first discharge port 2050, and into the first cylinder head 2080. Disposed between the first stage cylinder 2040 and the first cylinder head 2080, at the first discharge port (2050), is a first stage discharge valve 2055. The first stage discharge valve 2055 is configured to mitigate backflow of fluid into the first stage cylinder 2040. In some implementations, the first stage piston 2030 may be reciprocally accommodated within the first stage cylinder 2040, and connected by a first connecting rod 2090 to a first crankshaft 2100 within the crankcase 1020.
In some implementations, as illustrated in
As illustrated in
A second stage piston 2295 may be reciprocally mounted within the second stage cylinder 2280, wherein the second stage piston 2295 is mounted such that it may reciprocate axially within the second stage cylinder 2280. The reciprocation of the second stage piston 2295 can create a negative relative pressure to pull fluid into the second stage cylinder 2280 on a suction stroke where the piston is moving radially inward towards the crankshaft 1100. Further, a second stage discharge valve 2315 may be downstream of and in fluid communication with the second stage cylinder 2280. The second stage discharge valve 2315 may be disposed at a second discharge port 2310 fluidly coupling the second stage cylinder 2280 to a second stage discharge line 2340. The second discharge port 2310 fluidly couples the second stage cylinder 2280 to a second stage cylinder discharge head 2275. The second stage discharge valve 2315 is configured to mitigate the backflow of fluid from the second stage discharge head 2320 into the second stage cylinder 2280. A second stage discharge line 2340 may be in downstream fluid communication with and connected to the second stage cylinder discharge head 2320, wherein fluid may flow during a discharge stroke.
The compressor assembly may also feature a plurality of cylinders that are offset from one another, improving the system's balance, power, fluid flowrate and operational smoothness. This configuration is also beneficial in reducing vibrations and providing for a more stable operation. In other embodiments, the two-stage compressor 2220 may be configured such that a fluid is first compressed in the first stage cylinder 2040 to an intermediate pressure and then pushed through the interstage line 2240 and through the inline cooler 3052 before being compressed again in the second stage cylinder 2280. In some implementations, the first stage cylinder 2040 and first stage piston 2030 can comprise a larger displacement than the second stage cylinder 2280, as is illustrated. In some implementations, the cylinders may have the same stroke length but different bore diameters, with the smaller second stage cylinder 2280 receiving fluid not from the crankcase 1020 but from the first cylinder head 2080 via the interstage line 2240. In these implementations, the arrangement can reduce the use of a crankcase ventilation line, and may mitigate capacity loss, reduce temperature increases at the inlet and outlet, and reduce parasitic power losses. Consequently, the overall performance, efficiency, and longevity of the two-stage compressor 2220 may be improved by the implementations and variations thereof described herein.
With continued reference to
As illustrated in
In some implementations the second stage suction valve 2290 may be located on or attached to the second stage discharge head with dual chambers for suction 2520 and discharge 2320 rather than on the second stage piston 2295. In this example, this may enable supercharging of the first stage piston 2030 and first stage cylinder 2040. As such, in operation supercharging may occur during the suction stroke, where, after fluid has already entered the crankcase 1020 during the discharge stroke, the radial inward displacement of the second stage piston 2295 further pressurizes the crankcase 1020. This pressure is communicated to the first stage cylinder 2040, resulting in a supercharged first stage cylinder operating at a pressure above the standard first stage suction pressure. This can result in a two-stage compressor 2220 capable of functioning as a three-stage compressor using only two cylinders.
In further embodiments, during the suction stroke operation, both the first stage piston 2030 and second stage piston 2295 move radially inward, and the volume of the crankcase 1020 decreases by the combined displacement of the two pistons. During this suction stroke, the first stage cylinder 2040 is filled with fluid passing from the crankcase 1020 through the first stage piston suction valve 2035 in the first stage piston 2030, and into the first stage cylinder 2040. During the suction stroke, the second stage cylinder 2280 is fed fluid from the second stage suction line 2240. The fluid flows from the second stage suction line 2240 through the second stage suction valve 2290 operating between the second cylinder suction head 2260 and the second stage cylinder 2280, causing pressure to build in the second stage cylinder 2280. This can assist the radial inward displacement of the second stage piston 2295 during the following suction stroke. This pressure assisted displacement of the second stage piston 2295 serves to compress the fluid in the crankcase 1020 to a pressure higher than the compressor's suction pressure. This higher pressure is forced into the first stage cylinder 2040, supercharging it to a pressure above the compressor's inlet pressure (e.g., suction pressure) thereby supercharging the first stage cylinder 2040.
In other implementations, the internal volume of the crankcase 1020 may be altered or sized larger or smaller depending on the application. In some embodiments, implementing a smaller volume may lead to more effective supercharging of the first stage cylinder 2040, while implementing a larger volume may reduce this effect. Some of the benefits derived from this implementation include improved volumetric efficiency, increased compressor capacity (beyond that of a typical two-stage compressor), the ability to achieve higher compression ratios, and the provision of three stages of compression (supercharging, first stage compression, and second stage compression) within a two-cylinder framework.
As an example, an amount of supercharging can be dependent on the relative volumes of the first stage cylinder 2040 and the second stage cylinder 2280, and the volume of the crankcase 1020. First and second stage cylinders with similar sizes can provide a greater supercharging capability than cylinder sizes with a larger displacement difference. For example, a compressor with a 4 inch diameter first stage cylinder 2040 and a 3 inch diameter second stage cylinder 2280 can have a greater supercharging effect than one with a 4 inch diameter first stage cylinder 2040 and a 2 inch diameter second stage cylinder 2280. A crankcase 1020 with a smaller internal volume can allow more supercharging of the first stage cylinder 2040, whereas a crankcase 1020 with a larger volume may partially dampen the supercharging effect. The implementations have been described, hereinabove.
In another implementation, the innovative piston and valve arrangement may be used in a supercharged single stage compressor. In these implementations, the supercharging effect described above for the two-stage compressor can also be applied to a single stage compressor. As illustrated in
A crankcase suction valve 620 is disposed at a suction port 622, which fluidly couples the suction line 616 with the crankcase 618. The crankcase suction valve 620 is configured to merely allow fluid flow from the suction line 616 to the crankcase 618. A piston suction valve 624 is disposed at a piston port 626, in the active or first piston 606. The piston port 626 fluidly couples the crankcase 618 with the acting cylinder 602. The piston suction valve 624 is configured to merely allow fluid flow from the crankcase 618 to the acting cylinder 602. A discharge valve 628 is disposed at a discharge port 630, in between the acting cylinder 602 and the acting cylinder head 610. The discharge port 630 fluidly couples the acting cylinder 602 with the acting cylinder head 610. The discharge valve 624 is configured to merely allow fluid flow from the acting cylinder 602 to the acting cylinder head 610.
In operation, in this implementation, during the compressor's 600 discharge stroke, the pistons 606, 608 move outward, increasing the crankcase's 618 internal volume by the displaced volume (e.g., cylinder cross sectional area X stroke length) of the two pistons 606, 608 combined. This increasing internal crankcase volume draws fluid from the suction line 616, through the crankcase suction port 622 and valve 620, and into the crankcase 618 in a volume equal to the combined displaced volume of the two pistons. During this stroke, fluid is also forced from the active cylinder 602 into the first discharge pipe 612, by passing through the discharge port 630 and discharge valve 624, and into the acting cylinder head 610. Further, during this stroke, fluid passes from the supercharging or second cylinder 604, through the second discharge line 614, and back to the inlet or suction line 616.
Additionally, supercharging can occur during the suction stroke. During the suction stroke, as the pistons 608, 606 move inward, the internal volume of the crankcase 618 is decreased by the combined displaced volume of the two pistons 608, 606. The crankcase suction valve 620 closes and mitigates fluid flow from the crankcase 618 into the suction pipe 616. As the crankcase volume contracts, fluid is forced from the crankcase 618 into the active cylinder 602, through the active piston 606, the active piston port 626, and active piston's suction valve 624, into the active cylinder 602. Because the reduction in crankcase volume is greater than the displaced volume of the active piston 606 alone, the active cylinder 602 is supercharged to a pressure greater than the pressure in the suction pipe 616. This results in a denser “charge” of gas in the active cylinder 602, a higher effective suction pressure, a lower effective compression ratio, a higher volumetric efficiency, and a higher mass flow rate, when compared to a non-supercharged cylinder. This action can also increase the compressor's ability to attain higher compression ratios overall. Because of the boosted inlet pressure, a supercharged single stage compressor cylinder can reach a higher overall compression ratio than a similar non-supercharged compressor. The supercharged single stage compressor may be as effective as a two-stage compressor.
In some implementations, the supercharging effect can be adjusted by varying the displacement of the supercharging piston (e.g., 608). For example, a larger diameter piston or longer stroke can provide more supercharging effect. As an example, a compressor with a 3 inch diameter active cylinder and a 4 inch diameter supercharging cylinder can provide more supercharging effect than one with a 3 inch diameter active cylinder and a 2 inch diameter supercharging cylinder. The supercharging piston (e.g., 608) may or may not have the same diameter or stroke length as the active piston (e.g., 606). In a multi-cylinder arrangement, the number of supercharging cylinders may or may not match the number of active cylinders. As another example, a smaller internal crankcase volume can allow more supercharging, whereas a larger internal crankcase volume will partially dampen the supercharging effect.
In some implementations, a single stage compressor with supercharging cylinder using valves in the crankcase and the active cylinder, as described herein, can provide similar benefits to those of a two-stage compressor, by boosting or “supercharging” the first stage cylinder during the suction stroke. In this example, this supercharging increases the compressor's flow rate, improves the compressor's volumetric efficiency, and provides higher efficiency from a unit flow/unit power basis. Compressors of this design may be useful for applications requiring low flow but high pressure. Traditional single stage compressors might be unable to meet the operating conditions of these applications or might operate only at low volumetric efficiency. Compared to a conventional two-stage compressor, the supercharged single stage compressor described herein can have fewer parts. Like a two-stage compressor, the single stage contains a second cylinder and piston (the supercharging cylinder), but that second cylinder contains no valves. As such, the single stage may be simpler and less expensive to build and repair. Having fewer valves may result in fewer potential points of wear and ultimately failure.
It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/604,341, entitled COMPRESSOR WITH SUCTION VALVES IN PISTON AND CRANKCASE, filed Nov. 30, 2023, which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63604341 | Nov 2023 | US |
