Micro Magnetic Gear Pumps Support PandaX at China Jinping Underground Laboratory

Recently, the authoritative international refrigeration journal International Journal of Refrigerationpublished a paper titled "Thermal management design and key technology validation for PandaX underground experiment". The paper dedicates significant length to state the crucial role played by micro gear pumps in the experimental setup's cooling system​ and acknowledges the technical support provided by the pump supplier.

In the Acknowledgments section, the authors specifically express thanks for the technical support from Qiangxing Lin of Shanghai Super Fluid Industrial Co., Ltd.

In the journey to explore the mysteries of the universe, the China Jinping Underground Laboratory PandaX (PandaX project)​ stands as a national major science project dedicated to dark matter detection and neutrino research, representing the pinnacle of China's efforts in fundamental physics. Relying on the exceptional performance of its core product — the NP Series micro magnetic gear pumps​ — Suofu successfully participated in this project, providing key technical support for the cooling system of the experimental apparatus, thereby aiding breakthroughs at the scientific frontier.

1. Sino National Scientific Project: The Mission and Significance of PandaX

The PandaX experiment is a leading Chinese deep-underground dark matter detection project located at the world's deepest Jinping Underground Laboratory (CJPL). It aims to capture signals of dark matter particles using highly sensitive liquid xenon detectors. This project, a collaboration among top institutions like Tsinghua University and Shanghai Jiao Tong University, is listed as a National Major Science and Technology Infrastructure. Its research findings hold milestone significance for particle physics and cosmology.

• International Standard Experiment:​ The experiment requires the detector to operate stably in an ultra-low temperature environment of 178±0.1 K. The reliability and precision of the cooling system are directly related to the accuracy of the detection data.

• Technical Challenges:​ Processes such as liquid xenon purification and cryogenic temperature control must overcome stringent conditions including extremely low temperatures, high cleanliness requirements, and leak-free operation.

2. Suofu Technology: Facilitating the Progress of the PandaX Experiment

Within the cooling system of the PandaX experiment, Suofu's NP Series micro magnetic gear pumps were selected as the core equipment for coolant circulation drive. Their technical characteristics perfectly match the high-standard requirements of a national-level project:

Figure 1: Gear Pump Location Diagram

1. Leak-Free Design, Ensuring Experimental Safety

   Utilizing a magnetic coupling and fully welded pump body, it completely eliminates the risk of coolant (e.g., ethanol) leakage, meeting the extreme safety requirements for equipment in an underground laboratory. It avoids the wear issues associated with traditional mechanical seal pumps, ensuring long-term maintenance-free operation and reducing the risk of experimental interruption.

2. Ultra-Low Temperature Tolerance, Ensuring Stable Experiment Progression

   Capable of operating across a wide temperature range from -120°C to 150°C (customized models Suofu micro magnetic gear pumps NP1700, NP900), it stably handles the extremely low-temperature environment​ (-120°C) involved in the liquid xenon purification process.

3. High-Precision Flow Control, Meeting Stringent Experimental Demands

   Microchannel heat exchangers require 3-6 bar pressure. The NP Series gear pumps maintain stable flow even under this pressure. The flow control​ precision of Suofu gear pumps reaches 0.1%. Combined with servo motor speed regulation, it precisely matches the cooling system's stringent requirements regarding flow fluctuations. (For comparison: with constant speed and a 0.5 bar pressure fluctuation, the flow fluctuation of a centrifugal pump is around 40%; whereas for a Suofu micro gear pump under a 4 bar pressure fluctuation, the flow fluctuation is only 5%.)

4. High-Pressure Output Enhancing Equipment Cooling Efficiency

   The ethanol coolant, in a highly turbulent state, experiences significantly improved heat exchange efficiency due to uneven pipe walls and cross-sectional changes. Simultaneously, high-speed turbulence can inhibit the deposition of solid microcrystals. However, this design increases flow resistance, necessitating reliance on a high-pressure circulation pump. Suofu gear pumps provide 2 MPa (20 Kg) output pressure and 0.09 MPa suction pressure, operating stably even at low temperatures. By placing the pump upstream of the evaporator, the impact of flow resistance on the system is reduced, and heat generation from the pump body interfering with the coolant is minimized, ensuring efficient refrigeration output from the ACR in extreme low-temperature environments.

5. Precise Control, Ensuring Accurate System Temperature Regulation

   When the PandaX detector and distillation column operate steadily at 178K, the cooling power demand is not high. However, temperature stability requirements are strict, with allowable errors of ±0.1K or even ±0.01K. The "Heat Load A" in the figure below (Figure 2) can be directly connected to the central cooling system. The design is based on a precision temperature-controlled cold head using the ACR, where the low-temperature coolant serves as the primary cooling source. The gear pump, due to its special pump body structure, enables precise flow accuracy control, ensuring the system's accurate temperature control.

Figure 2: Central Cooling System Heat Load Connection

6. Customized Service, Meeting Complex Requirements

   According to the PandaX experiment's layout, Suofu provided both servo​ and DC brushless motor drive solutions, adapting to confined spaces and special power supply environments.

3. Suofu: Serving National Strategy with Cutting-Edge Technology

Suofu's NP Series micro magnetic gear pumps are already widely used in aerospace, semiconductors, medical, agriculture, refrigeration, and other fields. Their participation in the PandaX project once again validates their technological leadership.

"We are deeply aware that the reliability requirements for components in national major scientific projects are rigorous. Suofu polishes every detail with a craftsman's spirit, helping China's basic scientific research advance to the world frontier."

— Lin Qiangxing, General Manager of Suofu

From the laboratory to the vast cosmos, Suofu safeguards national scientific exploration with innovative technology. In the future, we will continue to delve deeper into the field of micro pumps, providing 'Intelligently Made in China' solutions for more high-end scientific research and industrial scenarios!

(Note: Technical parameters in this article are sourced from the publicly available paper "Thermal management design and key technology validation for PandaX underground experiment" and Suofu's product test data.)

Shanghai Super Fluid Co., Ltd.

Shanghai Super Fluid Co., Ltd. (Suofu), has an R&D and sales center in Shanghai (Shanghai Suofu) and a production base in Sanming City, Fujian Province (Sanming Suofu). With its own R&D team and independent production factory, the company occupies a total area of 2000㎡, including a 1600㎡ production workshop and a 200㎡ warehouse. SUOFU is constructing a new plant covering 19 acres with a building area of 20,000 square meters. Sanming Suofu is recognized as a National High-Tech Enterprise​ and a Specialized, Refined, Distinctive, and Innovative (SRDI) Enterprise. Located in the Fujian Zhongguancun Science Park, the company has won the second prize in the Fujian Innovation and Entrepreneurship Competition and advanced to the national finals.

The company holds 29 patents​ and has participated in 25 national and provincial-level R&D projects.

Suofu Product Advantages:

• Special Gear Profile Design:​ Proprietary gear profile design provides excellent wear resistance andnear-pure rolling gear meshing.

• Special Cavity Profile Design:​ Adapts to operating conditions with wide-ranging outlet pressure variations, performing well under low pressure, high pressure, or short-term reversal.

• Pulsation-Free Outlet Pressure:​ High-precision part machining and structural design ensure smooth liquid delivery.

• One-Shot Injection Molded Gears:​ The working tooth surfaces of the gears are manufactured using high-precision one-shot injection molding without subsequent mechanical machining, ensuring gear working surface integrity.

• High-Precision Ceramic Shaft:​ High-precision ceramic shafts offer exceptional wear resistance and rigidity, ensuring reliable pump operation under abrasive liquid and high-pressure conditions.

• Capable of Long-Term Dry-Running Self-Priming:​ In applications requiring the pump's inlet vacuum to draw in the medium, the NP series products provide reliable performance.

• Multiple Motor Options Available:​ Options include AC explosion-proof, AC variable frequency, single-phase/three-phase AC, DC brushed, DC brushless, DC brushless with built-in driver, and shielded DC brushless motors with built-in driver.

#Original Statement:​ This article is original by Shanghai Super Fluid Co., Ltd. Please indicate the source when reprinting. We reserve all rights.