Draw up the "Evolution Pedigree Of Positive
Displacement Pump Machine and Creative design of Vacuum Pumps
Summary
Draw lessons from biological research methods, the author analysis and synthesis of a large number of past and present pump institutions and machinery, and then recognized. They are not isolated from each other because they are evolved through the excitation of functional requirements. Therefore, there must exist a kinship evolution between them. According to this, the author sort out "spiral evolution", "precession evolution" And "vortex evolution" and "differential evolution" and other evolutionary veins, some evolvement rules and some innovative design of vacuum pump machinery based on evolutionary pedigree and evolution rule were found in the process of compilation.
Abstract
After a synthetical analysis of the collected pump mechanisms and
machines, the author believes that, m biological studying, giraffe has
evoleved from original deer, man has evolved from ape, similar to this,
all kinds of pump mechanisms and machines are not isolated, they are related
to each other, some mechanisms are usually evolved from other mechanisms
under the stimulation of machinery function demanded by people. thus there
must be a genetic evolution relarionship among them according to this, the
author put forward the venation of screw evolution, precession evolution
and scroll evolution, and draw up the evolution pedigree.
In the paper, the author introduces some evolution law found in the
process of drawing up the evolution pedigree and some crative design of
vacuum pumps based on the evolution pedigree
Key words: vacuum pump, evolution, pedigree, innovation
First, the mechanical evolution of pump pedigree and preparation
Volume pump can produce cycle changes in the volume of cavity machinery can be designed as vacuum pumps, internal combustion engines, compressors, displacement pumps and pneumatic, hydraulic power machinery. The large volume of such mechanical pumps has a great impact on human economic activities. Over the past 100 years, people have invested a great deal of manpower and material resources in the development and cultivation of such pumps. There have been thousands of machinery and projects, Made a lot of prototypes, some such as the triangular piston Wankel internal combustion engine and trochanter-type vacuum pump, fixed-chip vacuum pump and some patented type of rotor pump and compressor and vacuum pump has also become a popular commodity for a certain period of time. However, most of them are eliminated or disappear under the principle of "natural selection and survival of the fittest" and become "specimens" and "fossils" for people to study. However, on the basis of epistemology, understanding the past can only be understood now: Only by grasping the past and deeply understanding now can we better predict and march toward the future. They are the wealth accumulated by the creative predecessors for their later innovative designs. To this people often do not have full understanding. In the machinery industry, for those that are historical, past, old, people tend to see them as being eliminated and abandoned in the process of development or innovation. However, from an evolutionary point of view, standing at the height of history to analyze and synthesize, they are exactly the basis of innovation. Because they were "brand new" in the past, the so-called "old" is relative, while the "new" and "old" are only different in historical time zones. From the time continuity, "old" New "basis, similar to the well-known" 586 "computer from" 486 "," 486 "from" 386 "and" 286 ".
In addition, the author also believes that in order to organize the heritage that history has given us, we can compare and draw lessons from some research methods and laws in biology. Because in the physical world that makes up nature, machinery is not a natural object, but a human being. It was created by humanity in its unarmed hands with nature to meet some of its own functional requirements. Therefore it can be broadly regarded as an extension of human organs. For example, chopsticks are an extension of manpower, bicycles are an extension of human legs, electronic computers are an extension of the human brain, and vacuum pumps are engineered and manufactured by humans that can not obtain a vacuum from nature. Including human beings, biological development and evolution are characterized by generation after generation, from original to modern, from low to advanced, from simple to complex, which includes both inheritance and inheritance, and more variation and innovation. Any machinery as one of the artifacts, its development is inspired by the requirements of human function, and its development closely with the development of mankind, so inevitably and the biological carried out in nature, "natural selection, fitness Survival "evolution is similar.
By the nineteenth century Darwin by Beagle cruises around the world, summarize the rich collection of biological data inspired by "evolution", the author collected a number of existing patents and data files in the pump institutions and machinery, in the After analyzing and synthesizing them, it is considered that the primitive horse that evolved from a primitive deer to a giraffe and a short, four-toe, to a modern horse that evolved into a tall, hoof-hoofed horse in the study of biology, resembled a frog in the form of a tadpole, a variety of pump mechanisms and machinery They are not isolated from one another. They are often evolved from basic, primitive, simple, low-level, similar, or similar institutions or machines evolving through the motivation of functional requirements.
Therefore, there must exist an evolutionary relationship between them. If we find out the relationship and sort out the evolutionary context, we will not only avoid the inefficient repetition of the exploration that has been done with our predecessors in the process of innovation, Can guide the initiation of innovative ideas because each evolutionary vein can extract the evolutionary laws that have been guiding and enlightening in the evolution that has taken place, and the end of the context is often the starting point for innovation, whereby the author Combing the typical basic structure of a crank rocker mechanism evolved into a single screw pump and spiral liquid ring pump and scroll pump, hemispherical swing rotor pump, differential pump and other pumps evolved context. [1]
Second, the evolution of the crank rocker mechanism evolved into a single screw pump context - four-bar mechanism and Moineau pump genetic relationship
Single-screw pump is a suitable for pumping thick fluid varactor pump, it can form a constant volume of the sealed chamber to inhale the fluid, and then continue to reduce the cavity discharge, in particular, it does not have into the valve To control the suction and discharge, but also has a large enough monomer chamber and smooth flow to meet the flow of viscous fluid, of course, it should also study whether it is possible to use as a vacuum pump, for which the evolution of the process can be analyzed and combed.
The main sealing element of the pump structure is an eccentric screw (rotor) 1 with a round section in cross section and a stator 2 with a double helical cavity with an elongated hole formed by two straight lines and two semi-circular arcs in section; 3 The eccentric screw 1 is eccentrically driven by a drive shaft 4 having a pair of universal joints. As the rotor turns, the left end begins to form a gradually increasing volume. After two revolutions of the rotor, the fluid is sucked up to form a helical closed cavity with two lead lengths and two middle and small small heads. The closed cavity is axially displaced and eventually disappears on the right end, thereby forming a " Suck "and" row. " This is a more esoteric principle of function, the structure is exceptionally simple machinery. However, its evolutionary process is analyzed in an "evolutionary" way, essentially evolving from a typical four-bar linkage.
As we all know, to conceive of a variable-body mechanism, in principle, only a pair of cyclical relative motion components in the body are sealed to form a closed cavity with a periodic change, thus a varactor pump mechanical.
The four-bar mechanism (crank rocker) is a typical, basic prototype (equivalent to the original single-celled organism in the organism) that uses the motion of either its crank, connecting rod, Capacity machinery. Figure A is the use of pendulum swing cycle design designed pendulum pump. The main drawback of this configuration is that the wobble sealing member has more unfavorable geometric factors, especially difficult to design a good sealing. However, sealing is an extremely important factor of a vacuum system, and thus it is difficult to obtain a high vacuum index.
Changes in the institutional dimensions tend to give rise to qualitative changes in the characteristics of the organization. If the pendulum is increased in length to infinity, the trajectory at point C will be a straight line, forming a typical reciprocating pump (Figure B) Performance and transmission characteristics of a very wide range of applications, in addition to car tractors and other piston internal combustion engine piston compressor and piston pump. The reciprocating vacuum pump is a robust, reliable and durable pump, but it is bulky and has a large clearance volume that can only be used in harsh vacuum environments.
Simplified structure is the designer's eternal pursuit, for which there have been used with a sliding pair of T-shaped connecting rod to omit the concept of the piston (Figure C), Obviously slip ring on the poor performance of the seal is the configuration is eliminated Become a "fossil" the main reason.
Shortening the linkage is one way to make the configuration compact. As the linkage and the crank evolve to the same length (Figure D), the configuration will be more compact and again produce a qualitative change in stroke that will be four times the r , This configuration, like a compact, but in fact complex, it is not easy to get a wide range of applications.
Figure E is a composite of Figure C and Figure D. That link with a circular structure. However, this causes again a problem of middle dead center, that is, at the middle of the stroke, the crank and the link overlap. Institutional movements will be uncertain. It is generally possible to solve this problem by cross-laminating two identical bodies (Fig. F) or adding a pair of planetary gears with a transmission ratio of 1: 2 as a virtual constraint "cardon mechanism" (Fig.
Further, if the innovative idea is intensified by the helical configuration, it evolves into a single-screw pump (Figure H) [2] [3] [4] . That is, the configuration of Fig. E is no longer superposition of stages, but an infinite number of configurations of Fig. E are spirally superposed in the axial direction. The circular cross-section connecting rod evolves into an eccentric screw along the axial direction, and the crankshaft evolves into an eccentric drive shaft with a pair of universal joints.
Spiral evolution is a key process in this evolutionary context. Single screw pump from another perspective for analysis, which at the same time can be seen as another spiral pump mechanism evolution vein formed.
In the history of mechanics, the slope is the development of plain pure linear motion because it is a composite of two mutually perpendicular movements. The bevel on the cylinder becomes a spiral. The work of using a spiral to produce motion can be traced back to the Age of Archimedes when an implement was used that used a rotating spiral to transport the material by friction (Fig. A), which has been in use ever since. In addition, vibrations can be used to transport the material in a spiral (Figure d). But none of them have a closed chamber with a periodic change, so they are not pumps. To form a positive displacement pump, there must be more than two components that have relative motion to create a changing closed volume.
Figure b is a configuration of the original screw pump showing the pumping of the fluid with a single rack of packing corresponding recesses in the helix. However, it can not be used as a positive displacement pump because periodic suction and discharge cycles require positive and negative helical rotation, and intake and exhaust valves must also be provided. In order to pump the fluid continuously and periodically, a pair of helical screw-on twin screw pumps appeared (Fig. C).
A worm-gear single-screw pump appears if the axis of rotation of the continuous packing member is perpendicular to the axis of the screw (Figure d). Twin screw pump and single screw pump in recent years, the more widely used, the development of more and more.
The stuffing element can be a fixed-axis rotation, it being obvious that a planet-like stuffing element is also conceivable. Figure e is a "planetary screw pump." The screw is driven by a 1: 2 planet gear with a planetary motion and stuffs the double-headed nut's spiral depression. In addition, added to fill the remaining space within the screw and eccentrically drive the screw components. Obviously because of the complex structure and the unfriendly sealing of the seal, it is not possible to design a pump of practical value, but it is the basis for the idea of ​​a Momeau pump. Its structural analysis shows that due to the fact that the depressions of the screw and the nut have been packed with each other, the movement must also be restricted to each other so that extra packing members can be removed. As for the eccentric drive, you can use the drive shaft with universal joints. When you come to these two analyzes and put them together is the birth of the Momeau pump.
If the trajectory of a straight line at any point on the planet gear indexing circle in the 1: 2 planetary mechanism (point C in Figure G) is familiar, then the reciprocating linear motion of point C will be further utilized. Reciprocating pump, so that the combination of the configuration and the configuration of Fig. E evolved to make it more logical for the idea of ​​a Moineau pump to emerge.
After a large number of Moineau pump promotion, one after another to deduce some new configurations.
When it works in deep wells (hundreds of meters deep), the elastic deformation of hundreds of meters of slender rods makes the universal joints on both ends appear unnecessary as power is transmitted downhole from the ground through the slender rods (Figure 1) And was omitted.
I triggered by the oil and gas mixing pump (Figure J) with this eccentric design straight. The pump due to the compressibility of gas, multi-stage compression of the screw tapered cross-section of the cone at the end of the top cone cross-section has been very small, and then placed on both ends of the drive shaft in the total length of the pump The two ends, the flexibility of the drive shaft can also save universal coupling.
If the use of flexible components can make the screw eccentric straight-line enlightenment, the further application of mechanics in the rack and even the movement of the rack can be interchangeable principle of evolution can be a discharge tube for the flexible member (corrugated elastic tube) , Eccentric screw rotation for the axis of rotation, is supported by the elastic element for the plane movement of the stator configuration (Figure K).
1: 2 is not the only option available for the gear ratio. The gear in the card mechanism may obviously be 3: 4, 5: 6, 9:10 and so on. As a result, a variety of multi-head screw and multi-head screw hole conjugate shown in Figure L to form a single screw pump variant structure. They are no longer similar in shape or cross section to prototypes, but they are indeed the distant relatives of the four-bar mechanism, with the evolution of "precession", "vortex evolution" and "differential evolution" Out of a variety of positive displacement pump, limited to space This article can only initially describe a simple evolutionary context.
Third, single-rod pump in the field of vacuum pump innovation - semi-screw vacuum pump research and development
Today's volumetric pump machinery has evolved and entered the space three-dimensional era 11l. People in the two-dimensional plane area has been difficult to innovate a new pump configuration. However, there is still a lot of room for innovation in 3D. Over the years, we have relied on evolutionary pedigrees to innovate the evolving context of single-screw pumps along with four-bar mechanisms such as spiral liquid ring pumps, solid-liquid spiral pumps, spiral vane pumps, Double-cavity screw pump and other new structure of the screw pump, and do a dozen prototypes, but did not reach the ideal situation, after we have done their research and development work to analyze and reflect on, we think that many new spiral The structure has not got rid of the concept of conventional spiral, that is, the spiral element is not left-handed, right-handed: the lead screw is bound to be a lead above: To increase the displacement will inevitably increase the lead, so the spiral pump must be fine long. However, the displacement and the lead is a linear relationship, and the outer diameter of the spiral is the square relationship. In other words, from the point of view of compactness and compactness, it is better to increase the outer diameter than to lengthen the lead. Can you design a "short, thick" type of screw pump? From "slender" and "stubby" and "left" and "right", "one" lead and "less than one" lead, this The contradictory contradictory words have foreshadowed the existence of exploratory spaces of innovation here. From the evolution of the line diagram b view, this is a general presentation of spiral pump books commonly used schematic. It is virtually impossible to be a practical pump, but if we abandon the notion of "right" or "left" and the complete spiral must be more than one, we have created a semi-screw pump that consists of half a left Spiral and half of the right spiral into a self-closing combination of spiral ", the" combination of spiral "only half lead to solve the continuous structure of Figure b suction row must make the screw periodic positive and negative rotation problem, because half The one-turn rotation of the "combined spiral" of the left and the right hand spirals allows the toothed-padded member to continuously stroke for only half a reciprocating stroke without the need for an in-line valve to create a continuous suction and discharge function. Show is the most promising semi-screw vacuum pump we are currently researching and developing, which is the crystallization of our long-term spiral vacuum pump research and development.From the evolution point of view, it is the same as the reciprocating vacuum pump, all from the four-bar mechanism.
Fourth, the conclusion
1, kinship is the logical treatment of objective history and the status quo
The concept of mechanical evolution and evolution draws on biology, however, the phenomenon of life of artificial things is not the same as the reproduction of living things. In the process of combing the evolution of the context, in dealing with some aspects, the same theme, different perspectives, often can yield a variety of results. In other words, their solution is not unique. The extension of the context can occur in the form of bifurcation or convergence of two parallel contexts. Therefore, the evolutionary contextualization is only a longitudinal logical treatment of the objective reality of mechanical development. The contextual relationship in the context refers to the basic functional requirements Cycle, varactor) as the subject of research, various types of mechanisms and machines that are generated under various kinds of performance requirements (for example, excellent sealing or high lifespan, compact structure, etc.) Its inherent characteristics of the framework of a comprehensive analysis of the intrinsic relationship between them. The arrangement of "generation" in the evolutionary process of generations is not completely time series either. They are not the exact relationship of blood relationship that "parent-child identification" has. However, as long as the analysis and synthesis are reasonable, the context and the compiled pedigree can be meaningful and useful. Because the core purpose of these tasks is to "learn from facts, then innovate," in order to promote the process of mechanical innovation.
2, distant cousins ​​in the context of evolution
The evolution of any kind of mechanism and machine has either a long or a short evolution. The new generation is born on the old basis. The new generation must inevitably come from the new generation. Therefore, the "metabolism" of mechanical evolution is a common law, and constant innovation is their eternal theme, this idea has been more or less accepted by people. However, people tend to limit their understanding to the evolution of adjacent generations and can not see the inherent relationship between them and distant generations, so they will look like tadpoles and frogs seen by observers with one-day lifespan: he will Think of the former as a creature swimming with the tail, while the latter is another creature that leaps on its limbs. This partial one-sided knowledge not only impedes people's further understanding of the vertical and horizontal mechanics, but also discourages the exploration of the mechanism of mechanical innovation and impedes the germination and formation of innovative ideas.
3, ending
After a new configuration innovation is designed, there are still a large number of detailed structural design, process design and material problems. Three years ago we have conducted many rounds of semi-screw vacuum pump prototype research and development work, until now basically completed the whole process of product trial. In addition, we also believe that according to the "evolutionary" theory, a new product innovation success is another new product innovation process, now we are non-stop follow-up innovation design work.
references:
[1] Weng Haishan, biological mechanical design system mechanical design, 97No. 3
[2] Liang Zhaogi et al., Planar Pump Spiral Evolution and Novel Screw Pump Fluid Engineering, 87No. 8
[3] Liang Zhaogi et al. Single screw pump stator wear analysis and improvement measures of fluid engineering, 91No. 7
[4] Yu Jianling, etc., the composition of a single screw pump and added TI Arts Fluid Machinery, 95No. 9
[5] Yu Jianling, etc., the design of spiral vane pump machinery should pay attention to the problem of compressor technology, 97No. 5
[6] Liang Zhaoji, etc., the development of positive displacement pump and pump fluid machinery, 89No. 7
[7] Liang Zhao ji A Knack Of Seeking New Mechanism for pumping
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