SJ 20720-1998 General specification for split-type Stirling refrigerators
Some standard content:
Military Standard for Electronic Industry of the People's Republic of China FL5911
SJ 20720 —1998
General specification for split Stirling cryocooler Issued on March 18, 1998 Implementation on May 1, 1998 Ministry of Electronics Industry of the People's Republic of China Military Standard for Electronic Industry of the People's Republic of China General specification for split Stirling cryocooler 1 Scope
SJ 20720-1998
1.1 This specification specifies the requirements, quality assurance provisions and delivery preparation of split Stirling cryocoolers (hereinafter referred to as split Stirling cryocoolers). The specific requirements and characteristics are specified in the corresponding detailed specifications. 1.2 Scope of application
This specification applies to the development and production of cryocoolers. 1.3 Model Specifications
1.3.1 Model
The model naming method of the refrigerator shall comply with the provisions of Appendix A (reference). 1.3.2 Cooling Capacity and Refrigeration Temperature
When the refrigeration temperature is 80K (or 77K), the recommended nominal cooling capacity provided by the refrigerator is 150mW, 250mW, 500mW, 750mW, 1000mW, 1500mW, 1750mW, 2000mW, 5000mW. The cooling capacity at other refrigeration temperatures shall comply with relevant regulations. 2 References
CB191-90 Packaging, storage and transportation graphic mark
GJB150.3-86 Environmental test methods for military equipment High temperature test GJB150.4-86 Environmental test methods for military equipment Low temperature test GJB150.5-86 Environmental test methods for military equipment Temperature shock test GJB150.16-86 Environmental test methods for military equipment Vibration test GJB150.18=86 Environmental test methods for military equipment Shock test GJB 179A-96 Counting sampling inspection procedures and tables GJB2712-96 Quality assurance requirements for measuring equipment Metrological confirmation system GJB299A-91 Electronic equipment reliability prediction manual SJ/T10462~93 Process management commonly used graphics comply with SI/T10531~94 Changes in process documents
The Ministry of Electronics Industry of the People's Republic of China Issued on March 18, 1998 Implemented on May 1, 1998
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SJ/T10320-92 Format of process documents
SJ 20720 - 1998
SJ/T 10324-92 Qualification of process documents 3 Requirements
3.1 Detailed specifications
Refrigerators shall comply with the provisions of this specification and detailed specifications. When the requirements of this specification conflict with those of detailed specifications, the detailed specifications shall prevail.
3.2 Qualification appraisal
Refrigerators submitted in accordance with this specification shall be products that have been qualified or approved for finalization. 3.3 Design, structure and materials
3.3.1 Design structure
The refrigerator consists of a compressor, an expander and a dedicated driving power supply; the compressor and the expander are connected by a thin tube to form a split structure, and the cold head of the expander provides a cold source of 80K (or 77K) or other temperatures to the cooled object. 3.3.2 Materials
The requirements for materials and parts of the refrigerator shall comply with the provisions of the detailed specifications. The materials and parts with corresponding standards or specifications shall comply with the requirements of the corresponding standards or specifications; the requirements for materials and parts without corresponding standards or specifications shall be specified in the detailed specifications.
3.4 Process
3.4.1 The process documents of the refrigerator shall comply with the provisions of SI/T10462, ST/T10531, SJ/T10320 and SJ/T10324. 3.4.2 The process specification shall at least include the following: a. Material specification; b. Material processing and treatment; c. Forming; d. Intermediate test; e. Assembly; final performance test; g. Tools, equipment and instruments. 3.5 Dimensions The dimensions of the refrigeration machine shall comply with the regulations (see 3.1). 3.6 Weight The weight of the refrigerator shall comply with the regulations (see 3.1). 3.7 Performance characteristics Unless otherwise specified, the refrigeration machine shall meet the following performance requirements under the condition that the ambient temperature is 23±5℃ and the heat dissipation is sufficient to ensure that the temperature rise of the compressor surface and the hot end surface of the expander is not higher than 15℃ of the ambient temperature. 3.7.1 Cooling time According to the test in 4.6.3, the time for the refrigerator to reach the specified cooling temperature shall comply with the regulations (see 3.1). 3.7.2 Cooling capacity
According to the test of 4.6.4, the cooling capacity of the refrigerator at the specified temperature shall comply with the provisions (see 3.1). 2
3.7.3 Input power
SJ 20720 - 1998
According to the test of 4.6.5, the input power of the refrigerator shall comply with the provisions (see 3.1). 3.7.4 Noise
According to the test of 4.6.6, the noise value of the refrigerator measured at a distance of 1.5m shall comply with the provisions (see 3.1). 3.7.5 Leakage rate
According to the test of 4.6.7, the leakage rate of the refrigerator shall not be greater than 1.33×10~4Pa-cm/s. 3.7.6 Cooling capacity adjustment (when applicable)
According to the test of 4.6.8, the refrigerator shall be able to adjust the cooling capacity within the specified range. 3.7.7 Working attitude
Tested in accordance with 4.6.9, the cooling capacity, input power and noise of the refrigerator in any direction shall comply with the provisions of 3.7.2, 3.7.3 and 3.7.4.
3.7.8 Strengthened test (when applicable)
Tested in accordance with 4.6.10, the refrigerator shall be subjected to a strengthened test for at least 12 hours. 3.8 Environmental conditions
Unless otherwise specified, the refrigerator shall be subjected to various environmental tests in accordance with the provisions of GIB150 or detailed specifications. 3.8.1 High temperature operation
The refrigerator shall be tested in accordance with 4.7.1 and shall meet the requirements of 3.7. 3.8.2 High temperature storage
The refrigerator shall be tested in accordance with 4.7.2 and shall meet the requirements of 3.7. 3.8.3 Low temperature operation
The refrigerator shall be tested in accordance with 4.7.3 and shall meet the requirements of 3.7. 3.8.4 Low temperature storage
Refrigerators shall be tested according to 4.7.4 and shall meet the requirements of 3.7. 3.8.5 Temperature shock
Refrigerators shall be tested according to 4.7.5 and shall meet the requirements of 3.7. 3.8.6 Vibration
Refrigerators shall be tested according to 4.7.6 and shall meet the requirements of 3.7. 3.8.7 Shock
Refrigerators shall be tested according to 4.7.7 and shall meet the requirements of 3.7. 3.9 Reliability
Refrigerator mean time to failure (MTTF) shall comply with the regulations. 3.10 Appearance quality
Refrigerator appearance quality shall comply with the detailed specifications and the following provisions. 3.10.1 Metal surface
The metal surface of the daily tested refrigerator shall be free of burrs, cracks, scratches and sand holes. 3.10.2 Surface after coating
The coating layer of the refrigerator shall be uniform, and the surface after coating shall be free of peeling, blisters, scratches or cracks; the painted surface shall be smooth and free of defects, blistering and shedding.
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4 Quality Assurance Provisions
4.1 Inspection Responsibility
SJ 20720 - 1998
Unless otherwise specified in the contract or order, the contractor shall be responsible for performing all inspection requirements specified in this specification. Unless otherwise specified in the contract or order, the contractor may use its own or any other equipment suitable for completing the inspection requirements specified in this specification, except where not permitted by the certification agency. If necessary, the ordering party or the certification agency has the right to inspect any inspection item specified in this specification to ensure that the supply and service meet the specified requirements. 4.1.1 Responsibility for Conformity
All products must meet all the requirements of Chapter 3 and Chapter 5 of this specification. The inspections specified in this specification shall be an integral part of the contractor's overall inspection system or quality assurance program. If the contract includes inspection requirements not specified in this specification, the contractor shall also ensure that the products submitted for acceptance meet the contract requirements. Sampling for quality consistency inspection does not allow the submission of products that are known to be defective, nor can the ordering party be required to accept defective products. 4.1.2 Test equipment and inspection devices
The contractor shall establish and maintain test equipment, measuring equipment and inspection devices with sufficient accuracy and quantity to carry out the required inspections. At the same time, the contractor shall establish and maintain a metrological standard system in accordance with GJB2712 to control the accuracy of the measuring and test equipment.
4.2 Inspection classification
Refrigerator inspection is divided into:
a. Identification inspection (see Article 4.3);
b. Quality consistency inspection (see Article 4.4). 4.2.1 Production batch
A production batch shall consist of refrigerators manufactured under the same conditions using the same design, process, material and equipment. 4.2.2 Inspection batch
The contractor shall submit all refrigerators for quality consistency inspection within the specified time to determine whether they meet the requirements of the detailed specifications and this specification.
An inspection batch may consist of a production batch group or several production batches manufactured under essentially the same conditions (materials, processes, equipment, etc.).
4.2.3 Resubmitted batches
The resubmitted batches shall be separated from the newly submitted batches and can be clearly identified as resubmitted batches. When any batch submitted for quality consistency inspection fails to meet any of the requirements of Group A and Group C inspections, a stricter inspection may be adopted and the unqualified batches shall be resubmitted.
4.3 Qualification inspection
Qualification inspection shall be conducted in a laboratory approved by the superior qualifier. The sample unit shall be a refrigerator produced by equipment and quality assurance procedures that are in normal operation in production, and the sample shall be no less than 2 units. Qualification inspection consists of inspection and testing.
4.3.1 Inspection
All materials, parts, processes and components shall comply with the requirements of the corresponding specifications and be inspected according to the requirements of Table 1; sampling shall be carried out at the level of general inspection II in GJB179A. The AQL for mechanical inspection is 2.5: the AQL for visual inspection is 4. —41
Inspection items
Design structure
Defects and damages of components
Overall dimensions
Appearance quality
4.3.2 Inspection
SJ 20720 - 1998
Table inspection
Requirements Article number
After passing the inspection in accordance with 4.3.1, select 2 refrigerators for inspection in accordance with Table 2. Failure to meet any of the inspection items shall be grounds for refusing to grant the appraisal approval. Table 2 Identification inspection
Inspection items
Appearance and mechanical inspection
Cooling time
Cooling capacity
Power input
Leakage rate
Cooling capacity adjustment (when applicable)
Working posture
Strengthening test (when applicable)
High temperature operation
High temperature storage
Low temperature operation
Low temperature storage
Temperature shock
Reliability
4.3.3 Maintenance of qualified identification
Requirement Chapter number
3.3, 3.4, 3.5, 3.6, 3.10
Method Chapter number| |tt||To maintain the qualification, the contractor shall submit a report to the certification body every year. The report shall include a summary of the inspection results of Group A and Group C, and shall at least state the number of batches that have passed the inspection and the number of batches that have failed; the number and type of any part failures; the test items completed in a year; and the test results of all repair batches shall be identified and stated. Failure to submit a report within 30 days before the end of each year will result in the loss of qualification of the product. In addition to the periodic submission of inspection data, at any time during the year, if the inspection data show that the qualified products cannot meet the requirements of this specification, the contractor shall immediately notify the certification body. 4.4 Quality consistency inspection
Quality consistency inspection shall be carried out in accordance with the requirements of Group A, Group C and detailed specifications (see Table 3 and Table 4). Group A is a batch-by-batch inspection, and Group C is a periodic inspection.
4.4.1 Unqualified
For batches that fail to meet the requirements of Group A or Group C, the contractor shall analyze the reasons for the unqualified batches, take corrective measures, and resubmit them in accordance with the provisions of 4.2.3. If they are not submitted or the resubmission is unqualified, the batch shall be rejected. 4.4.2 Inspection
4.4.2.1 Group A Inspection
Group A inspection shall be carried out after passing the inspection of 4.3.1. It consists of the items listed in Table 3. The test order can be arbitrary. Group A is 100% inspected and unqualified products are rejected.
Table 3 Group A inspection
Inspection items
Cooling time
Cooling capacity
Power input
Cooling capacity adjustment (when applicable)
Working state
Strengthening test (when applicable)
4.4.2.2 Group C inspection
Requirements Article number
Methods Article number
Group C inspection shall be sampled from the batches that have passed the Group A inspection. The batch sampling shall be in accordance with the provisions of 4.4.3.3, and the inspection cycle is 12 months. Group C inspection shall be carried out according to the items and sequence specified in Table 4. Table 4 Group C inspection
Inspection items
High temperature working
High temperature storage
Low temperature working
Low temperature storage
Temperature shock
Requirement number
Method Chapter number
Sampling procedure
See 4.4.2.2.1
4.4.2.2.1 Inspection sampling
SJ 20720 1998
Samples shall be randomly selected for each inspection batch as specified in Table 5. If one or more unqualified samples are found, the entire batch shall be rejected.
Table 5 Sampling plan for group C
100 ~ 299
300 ~ 499
500 ~999
Above 1000
4.4.2.2.2 Sample handling for group C
Samples inspected for group C shall not be delivered according to the contract or order. 4.5 Packaging inspection
It shall comply with the requirements of Chapter 5 of this specification and detailed specifications. 4.6 Inspection method
4.6.1 Test conditions
Unless otherwise specified, all measurements and tests shall be carried out under the following atmospheric conditions Temperature: 23±5℃:
Relative diffuseness: 20%~80%:
Air pressure: Air pressure of the test site.
4.6.2 Appearance and mechanical inspection
Number of samples
Use the ear and measuring tools or scales that meet the accuracy requirements to inspect the refrigerator according to the requirements of 3.3, 3.4, 3.5, 3.6, and 3.10.
4.6.3 Cooling time
4.6.3.1 Test equipment
The test equipment consists of four parts: test dewar (or vacuum cover), heat load, power supply and measuring instrument, vacuum acquisition equipment and test instrument.
4.6.3.1.1 The heat load consists of the following components: a. Copper block;
b. Temperature sensor;
c. Heater;
4.6.3.1.2 The heat load should have the following characteristics: a. The temperature sensor and the heater are installed on the copper block; b. When the heat load is cooled from 300K to 80K (or 77K) or other temperatures, it should be able to release the specified heat energy: C. The heater in the heat load should be able to provide the specified heating power; d. Fix the heat load on the bell head to ensure good thermal contact without damaging the cold head. 4.6.3.2 Test procedure
4.6.3.2.1 Installation methodbzxZ.net
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SJ 20720 -- 1998
a. The temperature sensor and the resistor are installed on the copper block; b. Fix the heat load on the cold head to ensure good thermal contact with the cold head: c. Connect the test dewar (or vacuum cover), vacuum acquisition equipment and test instruments. 4.6.3.2.2 Test
Test according to the following rules:
a. Start the refrigerator and use the temperature sensor to measure the temperature of the heat load installed on the cold head; b. Use a timer to measure the time for the cold head to drop from normal temperature to the specified cooling temperature, which should meet the requirements of 3.7.1. 4.6.4 Cooling capacity
4.6.4.1 Test equipment
It should meet the requirements of 4.6.3.1.
4.6.4.2 Test procedure
4.6.4.2.1 Installation method
It should meet the requirements of 4.6.3.2.1.
4.6.4.2.2 Test
Test according to the following rules:
a. Start the refrigerator and use the temperature sensor to measure the temperature of the cold head: b. When the temperature stops dropping, input heating power to the heat load; C. After the cold head temperature stabilizes at the specified cooling temperature for 20 minutes, measure the heating power of the heat load, which should meet the requirements of 3.7.2.
4.6.5 Power input
4.6.5.1 Test equipment
Should meet the requirements of 4.6.3.1.
4.6.5.2 Test procedure
4.6.5.2.1 Installation method
Should meet the requirements of 4.6.3.2.1.
4.6.5.2.2 Test
Start the refrigerator and measure the power input of the refrigerator under the conditions of specified cooling temperature and cooling capacity. It shall meet the requirements of 3.7.3.
4.6.6 Noise
4.6.6.1 Test
Test according to the following rules:
a. Under the condition of the specified cooling temperature, the refrigerator should be set to work in an environment where the background noise is 10dB lower than the sound pressure level of the noise being tested:
b. In the same plane of the refrigerator, at 4 positions with a difference of 90°, use a sound level meter to measure the sound pressure at a distance of 1.5m from the refrigerator, which should meet the requirements of 3.7.4.
4.6.7 Leakage rate
4.6.7.1 Test
Place the refrigerator in a sealed vacuum container and connect it to a hydrogen leak detector. Measure the leakage rate at an ambient temperature of 23±5, which should meet the requirements of 3.7.5.
4.6.8 Cooling capacity adjustment (when applicable)
4.6.8.1 Test
SJ 20720 - 1998
Adjust the working state and operating parameters of the refrigerator, and test the cooling capacity of the refrigerator according to 4.6.4. It should meet the requirements of 3.7.6.
4.6.9 Working posture
4.6.9.1 Test
Test according to the following details:
a: Provide heat dissipation according to the conditions specified in Article 3.7: b. Fix the refrigerator firmly on the test bench so that the axis direction of the cold finger is respectively covered in the horizontal, inclined 45° and vertical up and down four directions;
c. Test in the above four directions according to the provisions of 4.6.4, 4.6.5 and 4.6.6. The cooling capacity, input power and noise of the refrigerator should meet the requirements of Article 3.7.7. 4.6.10 Strengthening test (when applicable)
The refrigerator shall be subjected to the strengthening test for the specified time as shown in Figure 1 and shall comply with the requirements of 3.7.8. +℃
+23℃
-32℃
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4.7 Environmental test
S1 20720 - 1998
Unless otherwise specified, environmental tests shall be carried out in accordance with the provisions of GJB150. 4.7.1 High temperature operation
The test shall be carried out in accordance with the provisions of GJB150.3, and its specific requirements shall comply with the detailed specifications. 4.7.2 High temperature storage
The test shall be carried out in accordance with the provisions of GJB150.3, and its specific requirements shall comply with the detailed specifications. 4.7.3 Low temperature operation
The test shall be carried out in accordance with the provisions of GJB150.4, and its specific requirements shall comply with the detailed specifications. 4.7.4 Low temperature storage
Test according to GJB150.4, and the specific requirements shall comply with the detailed specifications. 4.7.5 Temperature shock
Test according to GJB150.5, and the specific requirements shall comply with the detailed specifications. 4.7.6 Vibration
Test according to GJB150.16, and the specific requirements shall comply with the detailed specifications. 4.7.7 Shock
Test according to CJB150.18, and the specific requirements shall comply with the detailed specifications. 4.8 Reliability
Reliability prediction according to GJB299A, and the specific requirements shall comply with the detailed specifications. 5 Delivery preparation
5.1 Packaging requirements
The refrigerator should have a special packaging box with shockproof protection. The box should contain the product manual and certificate of conformity, and the certificate of conformity should indicate;
Manufacturing unit;
b. Product model;
C. Detailed specification number;
d. Production and inspection date;
e. Inspector's seal;
f. Others.
5.2 Storage requirements
The refrigerator should be stored in a dry, ventilated warehouse with a temperature of ~10℃~+40℃ and a relative humidity of no more than 80%, free from the influence of corrosive gases.
5.3 Transportation requirements
The refrigerator should be transported in a firm packaging box, the outside of which should comply with the provisions of Article 5.1 and should have graphic signs such as "handle with care" and "keep away from moisture" in accordance with the provisions of GB191; the packaging box containing the refrigerator should be transported in the prescribed manner, and should avoid direct exposure to snow and mechanical collision during transportation.
6 Notes
6.1 Pre-wide application
SF 20720 -- 1998
Split-type Styling coolers that meet this specification are mainly intended for military infrared detector components and can also be used in other military equipment
6.2 Contents of order documents
Order documents should indicate the following:
a. Name, number and date of this specification; b. Name, number, date and model identification of applicable detailed specifications; requirements for protection, packaging and packing and applicable markings; c.
d. Others.
6.3 Definitions
6.3.1 Refrigeration temperatureRefrigeration temperatureIn a given working system, the indicated temperature of the cold end of the cooler when the cooler is working, in Kelvin (K). 6.3.2 Refrigeration capacityRefrigeration capacityThe heat power absorbed by the cooler at the specified refrigeration temperature, in watts (mW). 6.3.3 Cooling down time The time required for the refrigerator to start under normal working conditions and for the refrigeration humidity to drop from room temperature to the specified working temperature, in minutes (min).
6.3.4 Split Stiling cryocooler Split Stiling cryocooler The split Stiling cryocooler is a Stiling cycle refrigerator composed of two independent parts, the compressor and the expander, which are connected by a thin tube.
TKAoNKAca-3 Low temperature operation
Test according to GJB150.4, and the specific requirements shall comply with the detailed specifications. 4.7.4 Low temperature storage
Test according to GJB150.4, and the specific requirements shall comply with the detailed specifications. 4.7.5 Temperature shock
Test according to GJB150.5, and the specific requirements shall comply with the detailed specifications. 4.7.6 Vibration
Test according to GJB150.16, and the specific requirements shall comply with the detailed specifications. 4.7.7 Shock
Test according to CJB150.18, and the specific requirements shall comply with the detailed specifications. 4.8 Reliability
Reliability prediction according to GJB299A, and the specific requirements shall comply with the detailed specifications. 5 Delivery preparation
5.1 Packaging requirements
The refrigerator should have a special packaging box with shockproof protection. The box should contain product instructions and certificates. The certificate should indicate:
b. Manufacturing unit;
c. Product model;
d. Production and inspection date;
e. Inspector's seal;
f. Others.
5.2 Storage requirements
The refrigerator should be stored in a dry, ventilated warehouse without corrosive gas with a temperature of ~10℃~+40℃ and a relative humidity of no more than 80%.
5.3 Transportation requirements
The refrigerator should be transported in a firm packaging box. The outside of the box should comply with the provisions of Article 5.1 and should have the "handle with care" and "keep away from moisture" and other graphic signs in accordance with GB191. The packaging box containing the refrigerator should be transported in the prescribed manner and should avoid direct exposure to snow and mechanical collision during transportation.
6 Explanations
6.1 Pre-application
SF 20720 -- 1998
The split-type Stylin refrigerator that complies with this specification is mainly intended for military infrared detector components and can also be used for other military equipment
6.2 Contents of order documents
The order documents should indicate the following:
a. The name, number and date of this specification: b. The name, number, date and model identification of the applicable detailed specifications; the requirements for protection, packaging and packing and the applicable signs: c.
d. Others.
6.3 Definitions
6.3.1 Refrigeration temperaturerefrigerationtemperatureIn a given working system, the indicated temperature of the cold end of the refrigerator when it is working, in Kelvin (K). 6.3.2 Refrigeration capacityrefrigeration capacityThe heat power absorbed by the refrigerator at the specified refrigeration temperature, in watts (mW). 6.3.3 Cooling down timecoolingdowmtimeThe time required for the refrigeration humidity to drop from room temperature to the specified working temperature when the refrigerator is started under normal working conditions, in minutes (min).
6.3.4 Split Stiling cryocoolersplit Stiling cryocoolerA split Stiling cryocooler is a Stirling cycle refrigerator composed of two independent parts, a compressor and an expander, which are connected by a thin tube.
TKAoNKAca-3 Low temperature operation
Test according to GJB150.4, and the specific requirements shall comply with the detailed specifications. 4.7.4 Low temperature storage
Test according to GJB150.4, and the specific requirements shall comply with the detailed specifications. 4.7.5 Temperature shock
Test according to GJB150.5, and the specific requirements shall comply with the detailed specifications. 4.7.6 Vibration
Test according to GJB150.16, and the specific requirements shall comply with the detailed specifications. 4.7.7 Shock
Test according to CJB150.18, and the specific requirements shall comply with the detailed specifications. 4.8 Reliability
Reliability prediction according to GJB299A, and the specific requirements shall comply with the detailed specifications. 5 Delivery preparation
5.1 Packaging requirements
The refrigerator should have a special packaging box with shockproof protection. The box should contain product instructions and certificates. The certificate should indicate:
b. Manufacturing unit;
c. Product model;
d. Production and inspection date;
e. Inspector's seal;
f. Others.
5.2 Storage requirements
The refrigerator should be stored in a dry, ventilated warehouse without corrosive gas with a temperature of ~10℃~+40℃ and a relative humidity of no more than 80%.
5.3 Transportation requirements
The refrigerator should be transported in a firm packaging box. The outside of the box should comply with the provisions of Article 5.1 and should have the "handle with care" and "keep away from moisture" and other graphic signs in accordance with GB191. The packaging box containing the refrigerator should be transported in the prescribed manner and should avoid direct exposure to snow and mechanical collision during transportation.
6 Explanations
6.1 Pre-application
SF 20720 -- 1998
The split-type Stylin refrigerator that complies with this specification is mainly intended for military infrared detector components and can also be used for other military equipment
6.2 Contents of order documents
The order documents should indicate the following:
a. The name, number and date of this specification: b. The name, number, date and model identification of the applicable detailed specifications; the requirements for protection, packaging and packing and the applicable signs: c.
d. Others.
6.3 Definitions
6.3.1 Refrigeration temperaturerefrigerationtemperatureIn a given working system, the indicated temperature of the cold end of the refrigerator when it is working, in Kelvin (K). 6.3.2 Refrigeration capacityrefrigeration capacityThe heat power absorbed by the refrigerator at the specified refrigeration temperature, in watts (mW). 6.3.3 Cooling down timecoolingdowmtimeThe time required for the refrigeration humidity to drop from room temperature to the specified working temperature when the refrigerator is started under normal working conditions, in minutes (min).
6.3.4 Split Stiling cryocoolersplit Stiling cryocoolerA split Stiling cryocooler is a Stirling cycle refrigerator composed of two independent parts, a compressor and an expander, which are connected by a thin tube.
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