Unlocking High Vacuum: Customized Vacuum Pumps Solution To Meet Process Requirements

As it says, Vacuum boosted, like a tiger with wings.

A vacuum refers to a state characterized by pressure levels below atmospheric conditions, commonly encountered in settings such as the Tibetan plateau, outer space, and vacuum chambers. In these environments, pressure is considerably lower than the standard atmospheric pressure.

In everyday life, we often utilize vacuum technology in appliances like vacuum cleaners and range hoods. However, it’s important to clarify that the vacuum under discussion is distinct from the ‘vacuum suits’ sometimes associated with celebrities.

In the realm of nature, the gecko stands as a remarkable example of vacuum-related phenomena. Geckos exhibit extraordinary capabilities, enabling them to traverse walls, scale glass surfaces, and move effortlessly, akin to a real-life ‘Spider-Man.’ This incredible prowess is attributed to the gecko’s unique ‘vacuum suction cups’ on its feet.

The Power of Roots Screw Vacuum Pumps

The Roots screw vacuum group unit is a sophisticated amalgamation of multiple Roots pumps connected in series alongside a screw pump. This unit is thoughtfully outfitted with a range of accompanying components, including pipelines, valves, mounting structures, and electrical control cabinet. It operates seamlessly, with the initial screw pumps initiating the process. The Roots pumps are strategically governed by vacuum gauges and vacuum relays.

Notably, the Roots and screw pumps are designed with non-contacting components, resulting in a host of advantages. These benefits include a harmonious operational environment, minimal noise generation, reduced vibration, compact structure, and a small physical footprint.

This multi-stages Roots screw vacuum unit proves to be an exceptional pumping apparatus, delivering energy efficiency, substantial pumping capacity within high vacuum realms, and superior vacuum levels. Its utility extends to diverse industries such as electronics, coatings, metallurgy, heat treatment, drying, distillation, pharmaceuticals, and the chemical sector.

Notably, it caters to the stringent requirements of the semiconductor industry by eliminating oil vapor pollution. Additionally, it is a fitting choice for environments with high humidity and minimal dust content. Depending on specific vacuum degree prerequisites, users can opt for either a single Roots screw vacuum unit or a double Roots screw vacuum unit.

Why Do We Use Vacuum Technology?

The application of vacuum technology is firmly rooted in the realm of both industrial and artisanal enterprises, exemplifying a quintessential cross-cutting technology. It serves a multitude of functions such as packaging, drying, aspiration, material processing and product positioning.

In specific production processes reliant on technology, the operation necessitates the creation of a vacuum environment, given its inherent advantage of lower air pressure, particularly conducive for the production of temperature-sensitive products. Vacuum fractionators, for instance, enable the separation of azeotropic mixtures, rendering them indispensable in certain industrial processes.

The effective utilization of vacuum technology hinges upon the initial establishment of a vacuum. Consequently, the selection of an appropriate vacuum pump assumes paramount significance. Critical factors that require consideration encompass the desired final vacuum pressure, volume requirements, specific operational parameters germane to the application, and the most suitable compression principle tailored to the unique characteristics of the task at hand. Various operational scenarios demand distinct solutions.

In essence, the interconnection between vacuum technology and various industries is irrefutable. It forms a symbiotic relationship with sectors such as the metallurgical industry, electronics, machinery manufacturing, electrical products, new building materials, permanent magnetic materials, food and healthcare, chemical and pharmaceutical industries, and many more.

Today, countries worldwide are increasingly engaging in diverse scientific research endeavors, particularly in the field of space exploration. These pursuits necessitate the creation of high-vacuum, ultra-high vacuum, and very high vacuum conditions. The undeniable link between vacuum technology and these scientific explorations serves as concrete evidence.

Vacuum technology is not only integral to industrial production and scientific research but has also become an indispensable facet of our daily lives. As vacuum technology continues to advance and find application across various domains, the enhancement of material performance and quality, coupled with our comprehension and exploration of both materials and the mysteries of the universe, draws nearer and nearer.

Consequently, vacuum technology remains in a state of continuous evolution and integration across a multitude of sectors and processes. Importantly, each instance in which vacuum technology is introduced leads to a remarkable increase in both output and product quality, marking a geometric rise in performance.

What is Called High Vacuum?

The efficiency and precision of production processes are intricately linked to the vacuum source employed. The selection of a vacuum pump is inextricably tied to various factors, including the specific vacuum type, the methodology of vacuum generation, and the manner of vacuum regulation.

For a comprehensive grasp of vacuum technology, industry standards typically classify vacuum pressures into four distinct levels:

1. Rough vacuum: 10^3 to 1 mbar, this pressure difference obtained by using a low vacuum is used for clamping, lifting and transporting materials, as well as for dust extraction and filtration, e.g. hoovers, vacuum suction cups.
2. Fine vacuum: 1 to 0.001 mbar, this vacuum range is generally used to exclude the gas or moisture absorbed and dissolved in the materials, as well as vacuum heat insulation and insulation, such as vacuum freezing of foodstuffs, vacuum drying, vacuum packaging and so on.
3. High vacuum: 0.001 to 0.000001 mbar (10^1~10^5Pa), The use of high vacuum residual gas density is small, and the chemical interaction with any substance is weak, can be vacuum smelting, vacuum coating, distillation, the production of vacuum devices, etc.
4. Ultra-high vacuum: 0.000001 to 0.000000000001 mbar (primarily utilized for simulating space environments and advanced scientific research applications)

In the realm of rough and fine vacuum technology, piston vacuum pumps, Roots rotor vacuum pumps, and dry screw vacuum pumps exhibit promising applications.

The Roots screw vacuum unit operates in a multi-stage series configuration, employing the Roots pump as the primary pump and the screw pump as the fore stage pump. It features direct internal water cooling technology for the screw pump, facilitating the attainment of high vacuum requirements.

This series unit presents a unipolar, dry-running, non-contact screw vacuum pump. Its operation entails two parallel screws rotating in opposite directions, driven by synchronous transmission gears to ensure precise mutual alignment. Controlled clearances exist between the rotors and between the rotors and the pump body. Notably, the pump chamber is entirely devoid of oil or water, and the pump body is coated with rust-resistant and wear-resistant Hastelloy material.

Hastelloy composite anti-corrosion pumps are well-suited for handling materials containing chloride ions, fluoride ions, sulfate ions, nitrate ions, and other highly corrosive substances. They find applications across various fields, including molecular distillation, evaporation, drying, degassing, filtration, organic solvent recovery, biotechnology, and more.

This specialized vacuum unit possesses distinct advantages, particularly within the chemical, petrochemical, and pharmaceutical industries.

Our company provides comprehensive services, including sales, maintenance, and technical support for these vacuum pumps.

How Roots Screw Vacuum Pumps Work?

The Roots pump stands as a high-performance rotary exhaust vacuum pump, distinguished by its remarkable exhaust capacity and exceptional efficiency. Its design features two “8”-shaped rotors arranged perpendicularly on parallel shafts, meticulously synchronized in reverse rotation through a 1:1 gear ratio. The interplay between these rotors and the pump casing walls maintains precise clearances.

It’s essential to note that, as a vacuum pump without internal compression, the Roots pump generally has a low compression ratio, necessitating a preceding-stage pump for medium and high vacuum applications. Consequently, the ultimate vacuum of the Roots pump hinges on its structural design, manufacturing precision, and the ultimate vacuum of the preceding-stage pump.

The dry screw vacuum pump employs a pair of screws that execute synchronized, high-speed, counter-rotational movements within the pump casing, serving to aspirate and expel gases. These screws, fine-tuned and balanced, are supported by bearings and situated within the pump casing with specified clearances to prevent inter-screw friction.

Consequently, the pump operates smoothly, generates minimal noise, and avoids the need for lubricating oil within the working cavity. As a result, dry screw pumps are well-suited for removing gases containing substantial water vapor and minimal dust. They offer a superior ultimate vacuum, lower power consumption, and deliver on energy efficiency and maintenance-free operation. These pumps represent the next generation of vacuum pumps, surpassing the performance of traditional oil-sealed, water ring, and jet vacuum pumps.

With built-in, fully sealed, self-lubricating bearings, these pumps eliminate the need for lubrication within the workspace, thereby averting additional investments for oil disposal. They offer shorter pumping times, lower compression heating temperatures, excellent water evaporation performance, and outstanding suction performance. From an economic standpoint, these pumps are acclaimed for their high efficiency and variable speed capability. They can achieve vacuum levels as low as 0.001 mbar, making them a valuable asset for various applications.

Applications in Industries

Scope of Applications for Multi-stages Roots Screw Vacuum Unit:

1. Chemical and Pharmaceutical Industries: Utilized in product distillation, drying, degassing, and material conveying processes.
2. Electrical Engineering: Essential for applications such as transformer manufacturing, epoxy resin vacuum casting, capacitor vacuum oil immersion, and vacuum pressure impregnation.
3. Aerospace: Supports vacuum simulation experiments for spacecraft orbit modules, return modules, rocket attitude adjustment modules, spacesuits, astronauts’ extravehicular activities, and aircraft liftoff procedures.
4. Vacuum Coating: Applied in a range of coating processes, including vacuum evaporation coating, vacuum magnetron sputtering coating, continuous thin film winding coating, and ion plating.
5. Industrial Furnaces: Crucial for vacuum brazing, vacuum sintering, vacuum annealing, vacuum pressurized gas quenching, and vacuum debinding operations.
6. Drying Techniques: Employed for paraffin gas-phase drying, variable pressure vacuum drying, wood drying, freeze-drying of vegetable food products, and more.
7. Metallurgy: Encompasses applications such as special steel smelting, vacuum induction furnace processes, vacuum desulfurization, and degassing.

Advantages Over Other Vacuum Technologies

Advantages of Dry Roots Screw Vacuum Pumps:

1. Environmental Protection:
   • Eliminates Environmental Pressure: Dry roots screw vacuum pumps operate without the need for oil, steam, or other industrial substances in the pumping process, making them environmentally friendly.
   • Enhanced Product Quality: These pumps do not contaminate the process system, leading to improved product quality.
   • Corrosion-Free and Simplified Water Treatment: Dry operation means no corrosion and eliminates water quality treatment issues.
   • Efficient Material Recycling: Dry screw vacuum pumps prevent the mixing of pumped materials with oil or water, facilitating material recycling.
   • Cost Savings: No consumption of working mediums results in cost savings, and these pumps have minimal running costs with no wearing parts.
2. High Vacuum Performance, Efficiency, and Energy Savings:
   • Exceptional Ultimate Vacuum: Achieves an ultimate vacuum as high as 2-3Pa (A), surpassing traditional vacuum pumps by several orders of magnitude.
   • Single Pump Versatility: Replaces various conventional vacuum pumps, including water ring pumps, water jet pumps, steam jet pumps, reciprocating pumps, offering a cost-effective solution.
3. Compact Structure and Ease of Maintenance:
   • Simplified Design: Dry screw vacuum pumps consist of meshing single-ended pumps with no contact or friction. They operate reliably and are easy to maintain, requiring regular gear oil changes.
4. Versatility in Handling Liquids, Dust, and Corrosive Media:
   • Mechanical Robustness: The mechanical principles and smooth flow channels of dry screw vacuum pumps enable them to handle media containing liquids, dust, and even corrosive gases.
5. High Automation Levels:
   • Comprehensive System Solutions: These pumps offer system solutions, integrating end-to-host systems, PLC control, remote control, and group control.
   • Frequency Adjustment: Realize frequency adjustments to ensure stable negative pressure, enhancing automation and operational efficiency.

Disadvantages of Slide Valve Vacuum Pumps:

1. Contamination and Corrosion Issues: Slide valve pumps suffer from significant drawbacks due to the ingress of water vapor, dust, or corrosive substances during vacuum pumping, leading to several problems:
   • Vacuum Oil Contamination: These contaminants can emulsify the vacuum oil, causing contamination and deterioration of the oil.
   • Corrosion: The pump’s components can experience corrosion, particularly in the presence of corrosive substances. Over time, this corrosion leads to severe wear and a decrease in pumping efficiency.
   • Frequent Maintenance: Slide valve pumps require frequent replacement of vacuum oil and accessories, resulting in elevated maintenance costs.
2. High Power Consumption: Slide valve pumps consume a notable amount of power, making them less energy-efficient compared to alternatives like screw vacuum pumps.
3. Inability to Implement Frequency Conversion: These pumps lack the capability for frequency conversion adjustment, limiting their adaptability and responsiveness in various operating conditions.

Disadvantages of Water Ring Pumps:

1. Excessive Water Consumption and Environmental Impact: Water ring pumps exhibit several disadvantages, primarily associated with water usage:
   • High Water Consumption: These pumps require a substantial amount of water, which can pose environmental concerns and contribute to elevated water usage costs.
   • Sewage Discharge: The need for water results in the discharge of sewage, which can negatively impact the environment.
2. High Energy Consumption and Lack of Frequency Adjustment: Water ring pumps consume a considerable amount of energy, and they do not have the capability for frequency adjustment, limiting their energy efficiency and adaptability.
3. Temperature-Dependent Vacuum Degree: The vacuum degree provided by water ring pumps is significantly affected by water temperature. During warmer seasons, such as summer, the vacuum degree noticeably decreases, making these pumps less reliable for consistent vacuum operations.

Selection and Sizing

Before proceeding with the selection of a vacuum pump, it is essential to establish a foundation in understanding critical concepts related to vacuum systems and pressures:

1. Vacuum, Limit Relative Pressure, and Limit Absolute Pressure:
   • Vacuum: The degree of gas dilution in a vacuum state, often expressed as vacuum and measured in Pa.
   • Limit Relative Pressure: Represents how much lower the internal pressure is compared to atmospheric pressure, indicated with a negative value.
   • Limit Absolute Pressure: Measures the internal pressure concerning the theoretical vacuum pressure (0Pa).
2. Pumping Volume: This quantifies a vacuum pump’s pumping speed and is typically expressed in L/s or m³/h. It helps compensate for air leakage, allowing for efficient vacuum creation.

With these fundamental principles in mind, one can proceed with the formal selection of vacuum pumps, considering several key criteria:

1. Required Vacuum Degree for the Process:

• The vacuum pump’s working pressure must meet the process requirements, with the vacuum degree surpassing that of the vacuum equipment by half to one order of magnitude. For example, if the process necessitates a 100Pa (absolute pressure) vacuum, the vacuum pump should maintain a vacuum degree of at least 50Pa to 10Pa.

2. Pumping Volume (Pumping Rate) Required for the Process:

• The vacuum pump should deliver the necessary pumping rate (e.g., m³/h, L/S) to effectively remove gas, liquid, and solids at its working pressure. A specific formula can be employed for self-calculation.

3. Composition of the Pumped Object:

• Determine whether the pumped object is gas, liquid, or particles. If the pumped gas contains water vapor, particles, dust, or other impurities, the selection of a rotary vane vacuum pump should be approached with caution. In cases of higher vacuum degree requirements, pre-filtration using a filtering device may be necessary.
• Identify the corrosiveness of the pumped object (e.g., acidic, alkaline, or the pH value). If corrosive gases are present, pre-filtration or neutralization should be performed before considering a rotary vane vacuum pump.
• Assess whether the pumped object is contaminated with rubber or oil. In this regard, the choice of suitable vacuum equipment is essential, and auxiliary equipment, such as condensers or filters, should be considered for installation in the pump’s inlet pipeline.

4. Noise, Vibration, and Aesthetic Impact:

• Evaluate the impact of noise, vibration, and aesthetics on the working environment and the factory’s surroundings.

5. Quality, Transport, and Maintenance Costs:

• Prioritize equipment quality during the procurement process. Be mindful of associated transport and maintenance costs, as well as long-term repair and maintenance considerations. Remember the adage that “cheap is not always good” when making purchasing decisions.

6. Requirements for Oil Contamination in the Vacuum Chamber:

• Choose between oil, oil-free, semi-oil-free, dry, or wet vacuum pumps based on the required level of oil pollution control. Dry vacuum pumps are suitable for applications demanding zero oil or working fluids to reduce environmental impact and storage costs.

Configuration and Determination of Fore Stage Pumping Speed:

After selecting the primary vacuum pump, the next step involves configuring the fore stage pump. Several principles guide this process:

(1) Pre-Vacuum Conditions:

• The fore stage pump must generate the required pre-vacuum conditions for the main vacuum pump’s operation.
• It should effectively remove the maximum amount of gas produced by the main vacuum pump.
• The pre-pumping time should meet the maximum pressure at which the main pump’s inlet operates.

Each main vacuum pump has specific pre-pump configuration requirements:

(1) Vapor Flow Pump Fore Stage Configuration:

• Pumps, such as oil diffusion pumps, oil diffusion injection pumps, and augmentation pumps, require the fore stage pump to timely remove the maximum gas produced by the main pump.
• The effective pumping speed of the fore stage pump (Sq) should meet the equation: Sq > pg.S/pn or Qmax/pn.
• When selecting the fore stage pump, account for the reduction in pumping speed due to operating below atmospheric pressure.

(2) Roots Pump Configuration with Oil-Sealed Mechanical Pump:

• Roots pump configuration with an oil-sealed mechanical pump should meet the formula: Sp = (1/3 ~ 1/8) SL.
• Sp is the fore stage pump’s pumping speed, while SL is the Roots pump’s pumping speed.

(3) Roots Pump Configuration with Water Ring Pump for the Fore Stage:

• For Roots pump configuration with a water ring pump for the fore stage, choose the pumping speed based on experience: Ss = (1/3 ~ 1/5) SL.

(4) Roots Pump Tandem Unit:

• When using Roots pumps for higher vacuum levels, tandem configurations may be needed. There are two options: Roots pump – Roots pump – mechanical pump or Roots pump – Roots pump – water ring pump.
• Determine the pumping speed of the former Roots pump as SjL = (1/2 ~ 1/4) SL.

(5) Turbo Molecular Pump Front Stage Configuration:

• For turbo molecular pump configurations, the fore stage’s pumping speed should meet the condition: Sp > Qmax/pj.
• pj represents the turbo-molecular pump fore stage pressure (usually around 2Pa), and Qmax is the maximum flow rate. Ensure the Sp value fulfills the condition for optimal performance.

The selection of an appropriate vacuum pump group system is a comprehensive process, informed by industry experience, application-specific requirements, and various other influencing factors.

Emerging Trends and Innovations in Roots Screw Pump Technology:

1. High Efficiency and Energy Conservation:
   • The global emphasis on energy efficiency and environmental preservation has ushered in a pivotal transformation in screw pump technology. Traditional power equipment, like screw pumps, is under growing scrutiny to address energy-saving concerns. The future trajectory of screw pumps will be characterized by a heightened focus on energy efficiency and enhanced performance.
   • Innovations will encompass material selection, structural design, and process enhancements to optimize efficiency while reducing environmental impacts. The ongoing development and application of new materials will further minimize friction loss and noise, contributing to a more eco-friendly and sustainable approach.
2. Intelligent Solutions:
   • The ongoing advancement of technology has elevated the importance of intelligence across various industries, and the field of screw pumps is no exception. The future of screw pump technology will involve a profound shift towards intelligence, with upgrades and improvements in sensor technology and automatic control systems.
   • Sensors for monitoring pressure, flow, temperature, and more will enhance the precision and overall performance of screw pumps. Real-time monitoring and adjustments will be enabled, delivering superior operational parameters. Additionally, cloud computing, big data analytics, and other technical means will be leveraged to optimize the operation and management of screw pumps, making them more intelligent.
3. Miniaturization and Integration:
   • In specific applications like microfluidics and microreactors, the requirements for equipment are notably stringent. Traditional screw pumps often fall short of meeting the demands of these applications. Hence, a key direction for future screw pump development lies in miniaturization and integration.
   • Advances in micro and nanotechnology are driving research toward miniaturized screw pumps to facilitate efficient microfluidic transport. Furthermore, the integration of multiple screw pumps and complementary equipment like filters will enhance operational efficiency and convenience.
4. Multi-Field Coupling Analysis:
   • Industries such as petroleum and chemicals often encounter multi-field coupling phenomena, where interactions between flow, heat, and mass fields play a significant role. These complex interactions have a substantial impact on the performance and longevity of screw pumps.
   • A future avenue of development involves the creation of multi-field coupling models, simulations, and predictive tools for screw pumps operating in complex environments. These efforts aim to optimize pump structure and operating parameters, ultimately enhancing equipment efficiency and reliability.

Conclusion:

The future direction of roots screw pump technology will be characterized by intelligence, energy efficiency, miniaturization, integration, and multi-field coupling analysis. As science and technology continue to evolve, roots screw pumps will offer enhanced performance and find broader applications across various industries.