Description:1
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS PERFORMED.
A.
TECHNICAL FIELD OF THE INVENTION
[001] The present invention relates to bearing arrangement in screw compressors. The present invention more particularly relates to a novel configuration of multiple cylindrical 5 roller bearings arranged in series with the same internal clearance, enhancing load distribution, reliability, and efficiency while overcoming limitations of prior art bearing arrangements.
B. BACKGROUND OF THE INVENTION 10
[002] Bearings are essential components in machines, allowing rotating parts to move smoothly while handling loads. Different types of bearings are used in compressors and other mechanical systems to reduce friction and improve performance. However, existing designs have certain limitations.
[003] For example, US20090232691 describes a low-pressure screw compressor with rotor 15 shafts supported by bearings. It uses a combination of fixed and loose bearings, with springs to push the shafts toward the outlet side. While this design helps maintain clearance and stability, it does not fully address issues like bearing wear and load distribution over time.
[004] CN206144978 introduces a double-row cylindrical roller bearing designed to handle high radial loads. It reduces friction by modifying the roller surface, which improves load 20 capacity and lifespan. However, it does not address axial stability or the overall ease of manufacturing and assembling such bearings.
[005] US20210207652 proposes a double-row cylindrical roller bearing that combines cross and parallel roller arrangements. This setup provides high rigidity and better assembly efficiency at a lower cost. However, the unrestricted positioning of certain rollers may still 25 lead to variations in performance and increased friction in some sections.
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[006] While these prior inventions have made improvements, there is still a need for a bearing design that optimizes load handling, minimizes friction, and ensures long-term durability while being easy to manufacture and assemble. The present invention aims to address these gaps and provide an improved solution.
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C.
OBJECTS OF THE INVENTION
[007] The primary object of the present invention is to introduce an improved bearing arrangement for screw compressors that enhances performance, reliability, and efficiency while overcoming the limitations of prior designs.
[008] Another object of the present invention is to improve load handling in screw 10 compressors. The proposed arrangement distributes the load across multiple smaller bearings. This ensures even stress distribution, reducing the risk of premature wear and failure. Additionally, selecting bearings with identical internal clearance guarantees uniform load transfer, preventing overloading of any single bearing in the system.
[009] Yet another object of the present invention is to provide for bearings with enhance 15 durability and reliability. The use of multiple bearings with uniform clearance minimizes uneven wear, reduces maintenance needs, and extends the overall lifespan of the screw compressor. Since the arrangement in the present invention can handle higher loads without excessive stress on any individual component, the compressor operates more smoothly and with improved long-term stability. 20
[010] Yet another object of the present invention is to optimize performance at high speeds and high loads. By using multiple antifriction bearings instead of journal bearings, this invention eliminates these challenges while maintaining high-speed performance.
[011] Yet another object of the present invention is to provide a cost-effective and scalable solution. Arranging multiple smaller bearings in series provides a practical alternative that 25 does not require modifications to the compressor’s basic design. This makes it a flexible and easily adaptable solution for different compressor applications.
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[012] Yet another object of the present invention is to ensure ease of assembly and maintenance. This invention uses multiple single-row cylindrical roller bearings which not only simplifies manufacturing and assembly but also makes replacement and servicing easier, reducing downtime in industrial applications.
[013] Yet another object of the present invention is to introduce a previously unused bearing 5 configuration in screw compressors, making it novel and patentable. Prior art designs, such as US20090232691, use single loose bearings on the suction and discharge sides, while CN206144978 and US20210207652 rely on double-row cylindrical roller bearings with fixed inner and outer rings. In contrast, this invention employs multiple single-row cylindrical roller bearings with the same internal clearance, arranged in series, resulting in better load 10 management, reliability, and ease of assembly.
[014] Yet another object of the present invention is to ensure optimal performance. To ensure this, this invention also establishes a scientific method for selecting and arranging bearings. The required number of bearings is determined based on gas loads using the equation:
(L10)=(C/P)n(L10) = (C/P)^n(L10)=(C/P)n 15
where L10 represents the bearing’s rated life, C is the basic dynamic load rating, P is the equivalent dynamic bearing load, and n is the exponent (3.33 for roller bearings). By following this approach, the invention guarantees precise bearing selection for various compressor applications, optimizing both performance and longevity.
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D.
SUMMARY OF THE INVENTION
[015] The various embodiments of the present invention provide an improved bearing arrangement for screw compressors, enabling better load distribution, higher reliability, and enhanced efficiency in high-speed and high-load applications. The present invention overcomes various challenges such as load capacity limitations, lubrication challenges, 25 vibration issues, and increased maintenance needs by introducing a novel bearing arrangement, which consists of multiple single-row cylindrical roller bearings arranged in series, with each bearing having the same internal clearance. This arrangement ensures even
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load distribution across all bearings, thereby reducing stress on individual components and extending the overall lifespan of the compressor. The selection of bearings in this arrangement is based on gas load and ensures that the compressor operates at higher speeds and under greater radial loads without the limitations posed by traditional designs. By eliminating the need for journal bearings, the invention also removes issues related to 5 alignment, lubrication complexities, vibration, and wear, making the compressor more reliable and easier to maintain.
[016] According to one embodiment of the present invention, the screw compressor features multiple antifriction bearings on both the high-pressure and low-pressure sides, rather than using a single large antifriction bearing or journal bearing. The number of bearings used in the 10 arrangement is not arbitrary; it is determined based on gas loads and operational requirements. The bearings are arranged in a series configuration on the rotor shaft, ensuring that each bearing shares the load equally.
[017] According to another embodiment of the present invention, the bearings with the same internal clearance are used to ensure uniform load transfer, preventing situations where 15 differences in clearance lead to some bearings carrying excessive loads while others remain underutilized. This uniformity is essential for prolonging bearing life, improving compressor efficiency, and reducing maintenance costs. Additionally, since multiple bearings handle the load together, each bearing experiences less stress, resulting in lower friction, reduced heat generation, and improved long-term stability. 20
[018] According to yet another embodiment of the present invention, multiple single-row cylindrical roller bearings in series are provided ensure greater adaptability, enhanced performance, and easier assembly.
[019] According to another embodiment of the present invention, the selection of bearings follows a scientific approach based on the basic rating life equation: 25
L10=(C/P)nL10 = (C/P)^nL10=(C/P)n
Where:
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L10 is the basic rated life of the bearing,
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C is the basic dynamic load rating (in kN),
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P is the equivalent dynamic bearing load, and
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n is the life equation exponent (3.33 for roller bearings).
By applying this formula, the invention ensures that the correct type, size, and quantity of bearings are chosen to handle the specific gas loads of the screw compressor. This prevents 5 underperformance or premature bearing failure due to improper selection, making the compressor more reliable and efficient in long-term operation.
[020] According to yet another embodiment of the present invention, it also addresses critical design constraints in large gas screw compressors with high-pressure ratio requirements. The problem of rotor loads is effectively solved by distributing the load among multiple smaller 10 bearings, which not only reduces stress on individual bearings but also improves overall compressor performance.
[021] According to yet another embodiment of the present invention, this bearing arrangement allows the screw compressor to operate at higher speeds without the limitations of a single large antifriction bearing, which may experience excessive wear, overheating, or 15 speed-related inefficiencies.
[022] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by 20 way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
E.
BRIEF DESCRIPTION OF THE DRAWINGS 25
[023] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawing in
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which the cylindrical roller bearing, bearing housing, rotor shaft and internal clearance is illustrated.
F.
DETAILED DESCRIPTION OF THE INVENTION
[024] In the following detailed description, a reference is made to the accompanying drawings 5 that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. The embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting 10 sense.
[025] According to the invention, multiple antifriction bearings are installed on both the high-pressure and low-pressure sides of the compressor instead of using a single large bearing. These bearings are scientifically selected based on gas load calculations and arranged in series to evenly distribute the load. 15
[026] The selection of bearings for a screw compressor is a critical design consideration that directly impacts the efficiency, reliability, and longevity of the compressor system. Since the bearings in a screw compressor are subjected to high radial loads due to gas compression forces, it is essential to scientifically analyze the load distribution and select an optimal bearing arrangement to ensure smooth and durable operation. 20
[027] The present invention follows a structured approach to bearing selection, which is based on load analysis and industry-standard equations to determine the bearing life, capacity, and number of bearings required.
[028] Bearings in screw compressors experience variable dynamic loads, including:
Gas Loads: Generated due to the compression process within the screw rotors. 25
Radial Forces: Acting perpendicular to the rotor shaft due to pressure differentials inside the compressor.
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Axial Forces: Resulting from unbalanced pressure zones in the compression chamber.
Vibrational Stresses: Caused by misalignment, rotational imbalance, and external factors.
To ensure that the bearings can withstand these forces without premature failure, an accurate load calculation is required. The bearing life equation provides a structured method 5 to determine the expected lifespan of a bearing under given operational conditions.
[029] The bearing life is estimated using the industry-standard formula:
L10=(CP)nL10 = \left(\frac{C}{P}\right)^nL10=(PC)n
Where:
L10 = Basic rating life of the bearing (in millions of revolutions). 10
C = Basic dynamic load rating (in kN) – represents the load capacity of the bearing.
P = Equivalent dynamic bearing load (in kN) – the actual load acting on the bearing.
n = Exponent of the life equation (3.33 for cylindrical roller bearings).
This equation is widely used in the bearing industry to determine the theoretical service life of a bearing before failure due to fatigue. 15
[030] Step-by-Step Bearing Selection Process
Step 1: Determine the Equivalent Dynamic Load (P)
The first step is to calculate the actual load experienced by the bearing, which depends on:
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Compressor operating conditions (e.g., pressure, gas type, speed).
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Radial and axial load components. 20
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External forces such as vibration and misalignment.
[031] Select a Bearing Based on Dynamic Load Rating (C)
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Once the dynamic load P is determined, the next step is to choose a bearing with a dynamic load rating (C) high enough to sustain the applied load for the desired lifespan.
Using the bearing life equation:
(L10) = (C/P) n
Where: 5
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L10 is selected based on the required lifespan of the bearing (e.g., 100,000 hours of operation at a given speed).
•
P is the calculated equivalent dynamic load.
•
C is the required dynamic load rating of the bearing.
Manufacturers provide catalogs with C-values for different types and sizes of bearings, 10 allowing engineers to select the most suitable bearing.
[032] Determine the Required Number of Bearings
If a single bearing cannot handle the applied load, multiple bearings are used in series to distribute the load effectively.
[033] Ensuring Uniform Load Distribution with Identical Internal Clearance 15
One of the key innovations of the present invention is the use of multiple cylindrical roller bearings with identical internal clearance. Bearings with different internal clearances can lead to uneven load distribution, causing premature failure in some bearings while others remain underloaded. By ensuring uniform internal clearance, the system maintains balanced load-sharing across all bearings, reducing stress and extending bearing life. 20
The internal clearance of a bearing is defined as the total distance that one bearing ring can move relative to the other under zero load conditions. It is selected based on:
Operating temperature (thermal expansion).
Speed of rotation.
Compressor load conditions. 25
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[034] By scientifically calculating the load distribution, bearing life, and required number of bearings, the present invention ensures optimal load handling in high-speed screw compressors. The use of multiple cylindrical roller bearings with identical internal clearance guarantees balanced load distribution, increased lifespan, and higher reliability compared to traditional single-bearing or journal bearing arrangements. 5
This approach effectively eliminates common bearing failures, enhances the efficiency of screw compressors, and reduces maintenance costs, making it a significant advancement in compressor technology.
[035] The present invention introduces a novel bearing arrangement for screw compressors 10 by using multiple cylindrical roller bearings arranged in series instead of a single large antifriction bearing. This design significantly improves load distribution, durability, speed capabilities, and reliability while addressing the limitations of traditional bearing arrangements.
[036] By distributing the radial and axial loads across multiple bearings, the system ensures 15 balanced load sharing, preventing localized stress and premature failure. Unlike a single large bearing, which bears the entire load and is prone to excessive wear, multiple smaller bearings effectively reduce stress, enhancing the overall durability of the compressor. Additionally, smaller bearings operate at higher speeds with less friction and inertia, overcoming the speed limitations associated with larger bearings. This not only improves efficiency but also 20 minimizes heat generation and lubrication issues, leading to smoother operation and extended service life.
[037] To maintain uniform load distribution, all bearings in the series are selected with the same internal clearance, preventing any single bearing from being overloaded or underutilized. This ensures consistent performance and reduces the risk of failure. The 25 placement of bearings on both the high-pressure and low-pressure sides of the compressor provides enhanced support to the rotors, mitigating vibrational stresses and improving overall stability.
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[038] Compared to traditional single-bearing or journal-bearing configurations, this multi-bearing arrangement offers better resistance to bending moments, reduced friction, lower maintenance requirements, and higher reliability. By implementing this innovative bearing system, the invention enables high-load, high-speed screw compressors to operate with improved efficiency, increased durability, and extended operational life, making it a superior 5 solution for modern industrial applications.
[039] A key aspect of this invention is the optimization of internal clearance across all bearings used in the arrangement. Internal clearance refers to the gap between the rolling elements and the raceways inside a bearing, which plays a crucial role in load distribution and overall performance. By ensuring that all bearings in series have identical internal clearance, the 10 invention achieves uniform load sharing, preventing uneven stress distribution. In conventional bearing arrangements, slight variations in clearance can lead to differential loading, where some bearings experience excessive loads while others remain underutilized. This imbalance can cause premature failure of overloaded bearings, leading to increased maintenance costs and operational downtime. 15
[040] The use of identical internal clearance across all bearings eliminates these issues by maintaining even load distribution, reducing the risk of misalignment and ensuring smooth operation. Additionally, consistent internal clearance prevents unwanted vibrations, excessive friction, and heat buildup, all of which contribute to improved bearing life and system reliability. This optimization enhances the stability of the screw compressor, ensuring 20 long-term efficiency and reducing the likelihood of unexpected breakdowns.
[041] The innovative bearing arrangement is implemented on both the high-pressure and low-pressure sides of the screw compressor, ensuring balanced rotor support and efficient handling of gas loads.
[042] On the high-pressure side, where the gas compression force is at its maximum, multiple 25 cylindrical roller bearings arranged in series efficiently manage the increased radial and axial loads. Traditional single-bearing arrangements often struggle under high pressures, leading to rapid wear and reduced bearing lifespan. However, the multi-bearing configuration distributes the stress evenly, preventing localized failures and enhancing the durability of the system. 30
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[043] Similarly, on the low-pressure side, the same bearing arrangement is employed to provide smooth and stable operation. Although the loads on this side are lower than on the high-pressure side, maintaining a balanced bearing structure ensures uniform rotor support, minimizing misalignment issues and improving overall compressor efficiency. This symmetrical bearing configuration allows the screw compressor to function reliably under 5 varying load conditions, reducing maintenance requirements and increasing the overall operational lifespan of the machine.
[044] By implementing this optimized bearing arrangement on both ends of the compressor, the invention enhances performance, stability, and reliability, making it a superior solution for high-load, high-speed screw compressor applications. 10
[045] The innovative bearing arrangement introduced in this invention provides multiple advantages over conventional screw compressor setups, significantly improving performance, durability, and operational efficiency.
[046] One of the primary benefits is superior load management, achieved by using multiple cylindrical roller bearings arranged in series. This ensures that radial loads are evenly 15 distributed, preventing excessive stress on any single bearing, which in turn reduces wear and extends bearing life. Unlike conventional large single bearings, which may struggle under high loads and speed limitations, this arrangement allows for efficient high-speed operation, making it ideal for demanding industrial applications.
[047] Another critical advantage is the elimination of journal bearing drawbacks. Traditional 20 journal bearings suffer from issues related to alignment, lubrication, friction, and vibration, all of which negatively impact compressor efficiency and reliability. By replacing journal bearings with multiple antifriction bearings, the invention removes these inefficiencies, leading to a smoother and more stable operation.
[048] The design also simplifies maintenance and reduces costs. Since individual bearings can 25 be replaced without dismantling the entire system, the need for extensive downtime and expensive repairs is minimized. Additionally, the fixed center distance between rotors in screw compressors imposes a size limitation on a single large bearing. The present invention
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overcomes this constraint by using multiple smaller bearings, optimizing space utilization while maintaining structural integrity.
[049] Another significant benefit is improved energy efficiency. By reducing friction losses and ensuring optimal load distribution, the bearing arrangement lowers power consumption, making the compressor more energy-efficient. This directly contributes to cost savings in 5 power usage and extends the operational lifespan of the compressor.
The present invention introduces an advanced bearing arrangement for screw compressors, leveraging multiple single-row cylindrical roller bearings with identical internal clearance, arranged in series. This design offers a superior alternative to existing bearing configurations by: 10
i.
Eliminating the size and speed limitations associated with single large bearings.
ii.
Overcoming journal bearing issues related to alignment, lubrication, and wear.
iii.
Ensuring uniform load distribution, reducing premature failure and improving system stability.
iv.
Enabling high-speed operation, making the compressor more reliable and efficient. 15
v.
Reducing maintenance efforts and costs, making it a cost-effective industrial solution.
By enhancing performance, durability, and longevity, this invention optimizes the efficiency of screw compressors, making it an ideal choice for high-load, high-speed applications across various industrial sectors. 20 , Claims:We Claim: 5
1.
A multiple anti friction cylindrical roller bearing arrangement in gas screw compressor comprising
a rotor housing with a high-pressure side and a low-pressure side;
a rotor shaft supported by bearings on both the high-pressure and low-pressure sides;
antifriction bearings or journal bearings conventionally used to support the rotor shaft; 10
characterized in that
multiple cylindrical roller bearings are arranged in series on both the high-pressure and low-pressure sides of the compressor; 15
each of said cylindrical roller bearings has identical internal clearance; and
the number of cylindrical roller bearings is determined based on analytical load calculations.
2.
The multiple anti friction cylindrical roller bearing arrangement in gas screw 20 compressor as claimed in claim 1, wherein the cylindrical roller bearings are arranged in series to distribute the applied radial loads.
3.
The multiple anti friction cylindrical roller bearing arrangement in gas screw compressor as claimed in claim 1, wherein the cylindrical roller bearings are selected 25 based on the basic rating life equation:
(L10) = (C/P)^n
where:
L10 is the basic rating life,
C is the basic dynamic load rating (kN), 30
P is the equivalent dynamic bearing load, and
n is the life equation exponent.
4.
The multiple anti friction cylindrical roller bearing arrangement in gas screw compressor as claimed in claim 1, wherein the high-pressure side of the compressor 35 includes multiple cylindrical roller bearings arranged in series.
5.
The multiple anti friction cylindrical roller bearing arrangement in gas screw compressor as claimed in claim 1, herein the low-pressure side of the compressor includes multiple cylindrical roller bearings arranged in series. 40
6.
The multiple anti friction cylindrical roller bearing arrangement in gas screw compressor as claimed in claim 1, wherein the cylindrical roller bearings have identical internal clearance to maintain uniform load distribution.
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7.
The multiple anti friction cylindrical roller bearing arrangement in gas screw 5 compressor as claimed in claim 1, wherein the cylindrical roller bearings are positioned along the rotor shaft.
8.
The multiple anti friction cylindrical roller bearing arrangement in gas screw compressor as claimed in claim 1, wherein the cylindrical roller bearings are selected 10 based on their ability to withstand the applied radial loads.
9.
A process for configuring a bearing arrangement in a screw compressor, comprising:
a. selecting multiple cylindrical roller bearings based on analytical load calculations;
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b. arranging the selected bearings in series on both the high-pressure and low-pressure sides of the compressor; and
c. ensuring that all bearings have identical internal clearance.