Functional testing of electric blankets

Functional testing of electric blankets  

(I) Test items  

Electric blanket performance is determined by the following test items.  

-- Size and quality;  

-- temperature uniformity;  

-- heating time;  

-- temperature stability;  

-- Washing effect  

(2) General conditions of the test  

Unless otherwise specified, the tests shall be performed under the following conditions:  

Test Room:  

The test was conducted in a place with no forced convection air and an ambient temperature of 20℃±5℃.  

Power supply voltage:  

The supply voltage should be within the range of ± 1% of the rated voltage. If the blanket has a calibrated voltage range, the test report should indicate the voltage value used in the test.  

Placement of electric blanket:  

Any removable enclosures shall be fitted with flexible parts placed between insulation at least 100mm beyond the edge of the heating area.  

The insulation material consists of open-hole polyether:  

-- Number of holes: per cm;  

-- Specifying quality:  

Hardness: in accordance with the standard measured indentation up to 40% of 120N ~ 170N.  

Support the insulation completely with a 20mm piece of plywood at least 300mm off the ground.  

The thickness of the insulation material under the electric blanket is about 72mm.  

-- 7.2mm (electric blanket with top cover);  

-- 36mm (bottom electric blanket).  

(3) Functional performance test  

1. Size  

1.1 Measurement of flexible components and heating area size of electric blanket  

Under the condition of no tension, the electric blanket is laid on a plane, and 5 points are evenly distributed on the length and width for measurement, respectively calculating their arithmetic mean value.  

Note 1: Washable outer cover dimensions should also be measured in order to assess washing effectiveness.  

Note 2: The heating area refers to the area where the heating element roadway is fixed, including the central location of the heating element roadway  

Note 3: If the average distance between the heating element routes overlaps with the edge of the flexible part, the dimensions of the total heating area are equivalent to the dimensions of the flexible part.  

Dimensions are expressed in mm, accurate to 10mm.  

1.2 Measurement of flexible wire length  

Between the power entry end of the flexible component and the power plug.  

The length is expressed in m, accurate to 0.05m.  

1.3 Quality  

Mass measurement per unit area of flexible components.  

The mass of the electric blanket is measured after it is energized at the rated voltage for 3 hours without tension. The mass per unit area is calculated by dividing the mass by the area of the flexible component.  

Mass per unit area is expressed in g/m2, accurate to 10 g/m2.  

Note: Cords and other external components should not be included.  

2. Temperature uniformity  

Measurement of temperature uniformity of heating area.  

The temperature of the heating area is measured by thermocouple. If the controller is measurable, the test is performed and calculated at the maximum and minimum position of the controller. Weld the thermocouple used to measure the surface of the electric blanket to a copper or brass sheet of 25mm×25mm×0.5mm, place the copper sheet alternately on and between the heating element, and secure it by stitching or other suitable means. When measuring, make the side without temperature element on the copper plate and the use surface of the appliance (and then the side close to the user in normal use) contact, test points should be distributed in the heating area of the appliance, the number of test points should not be less than 16, and the length and width of the heating area of the test points should be evenly distributed. The distance between the center of the copper sheet and the edge of the heating area at both ends of the length is half of the distance between the test points in the length direction, and the test points should meet the requirement that the distance between the adjacent test points should not be more than 200mm.  

Temperature rise is measured after the steady state is established.  

The average value obtained by measuring each point is the average temperature appreciation of each heating area. The range of temperature rise is determined by the difference between maximum temperature rise and minimum temperature rise.  

Consistency is calculated as a percentage of the ratio of the number of test points with a heating area within ±2K of the mean temperature rise to the number of all measuring points within the heating area.  

Temperature uniformity is expressed in terms of temperature rise range and consistency. The temperature rise range is expressed as K, accurate to 1K. Consistency is expressed as a percentage, accurate to ± 1%.  

Note 1: Electric blankets whose temperature increases gradually from one end of the heating area to the other do not measure their temperature uniformity.  

Note 2: For multitemperature electric blankets other than note 1, the uniformity of each heating area shall be calculated separately.  

3. Heating time  

Measurement of electric blanket heating test.  

The test was carried out at 15℃±2℃, and the electric blanket was placed in this environment for at least 24h.  

The electric blanket is energized when its controller is set to the maximum position until the temperature rises to 15K, and the required time is recorded.  

Place the copper plate (2) in the center of the heating area to measure the temperature rise.  

The heating time is expressed in min, accurate to 1min.  

4. Temperature stability  

Measurement of temperature stability of controlled electric blankets.  

If the ambient temperature is kept at 20 ° C ±1 ° C, the electric blanket controller should be set at a position that can be powered on overnight for heating. If not feasible, the minimum position should be set for heating. After the stable state is established, the temperature rise should be measured according to (2) and the average temperature of the heating area should be calculated.  

If the blanket does not work under these conditions, reduce the ambient temperature until the blanket can work.  

The ambient temperature was reduced by 10K±1K, and the average temperature was calculated after the stable state was established.  

Among them:  

s1 refers to the average temperature of heating area when the ambient temperature is t1.  

s2 refers to the average temperature of heating area at ambient temperature t2.  

Temperature stability is expressed as a percentage, accurate to 1%.  

5. Washing effect  

The washing effect of electric blanket can be tested in terms of size.  

The electric blanket or its outer cover shall be washed three times according to the manufacturer's instructions, and the dimensions shall be measured by reference to 1.1.1.  

Among them:  

A1 is the area of the flexible part or detachable cover;  

A2 is the area of flexible parts or removable covers after washing.  

The shrinkage rate is expressed as a percentage, accurate to 1%.  

Note 1: If the S value is negative, it indicates elongation of the electric blanket.  

Note 2: If the manufacturer recommends a selective washing method, the effect will be specific to individual electric blankets.  

Four, the use of electric blanket precautions  

According to many experiences in the use of electric blankets at home, there are mainly two kinds of unsafe factors for electric blankets: one is caused by the improper use of electric blankets overheating caused by sparks, arc and other burning accidents; One is due to the insulation of the electric blanket is not good or insulation damage caused by electric shock accident.  

In order to ensure the safety and prolong the service life of the electric blanket and prevent and avoid the unsafe factors in the process of using the electric blanket, we need to know about the selection and use of electric blanket products and common sense  

Selection of electric blanket products:  

1), carefully choose cheap products, it is best to buy regular shopping malls, products should have the factory name, factory label and address, date of delivery and inspector seal and certificate of qualification;  

2), optional electric blanket with indicator light and protection device;  

3) From the appearance, the joint of the electric blanket is smooth and neat, the switch material is strong, the controller is sensitive, the power cord is marked with 3C, and the length of the power cord is not less than 1.5 meters stipulated by the national standard;  

Choose a standard product with a double helix hairline. Double-layer heating wire has automatic safety protection function and strong insulation performance.  

Pay attention to the electric blanket material texture, size. Electric blankets are generally made of needled non-woven fabric. Choose products with smooth, soft, clean, thick and solid stitch stitching, and the blanket size should meet the national standard (single blanket size is 160cm×80cm, double blanket size mainly includes 160cm×150cm,160cm×130cm,160cm×110cm, etc.).  

Don't be tempted by cheap products. There are some miscellaneous electric blanket products in the market, and the price is only 20 or 30 yuan each. These products are basically made of single-layer electric hot wire and recycled cloth. The size of some blankets and electric flexible wires is not up to standard, and the sealing performance of the power cord and hair hot wire is poor, which is easy to cause electric shock and fire accidents, endangering life safety and causing property losses. Experts suggest consumers try to buy well-known brands of electric blankets.  

Follow the instructions strictly. Consumers should read the instruction manual carefully before using the electric blanket and strictly observe the precautions. In particular, it should not be used together with other heaters such as foot stove and hot water bag. It should not be used by people who cannot care for themselves, infants or people who are not sensitive to heat to avoid burns in high temperature.                                        

Note the following when using:  

(1) Before using the electric blanket, please read the instruction manual in detail and operate in strict accordance with the instruction manual.  

(2) The power supply voltage and frequency used should be consistent with the rated voltage and frequency calibrated on the electric blanket.  

(3) The electric blanket should be strictly prohibited from folding. In the process of using the electric blanket, it is necessary to check frequently whether the electric blanket is stacked and pleated. If so, the pleats should be spread out before use.  

(4) Do not use electric blanket with other heat sources.  

(5) If the preheating electric blanket is used, it should be absolutely prohibited to power on all night. When the user goes to bed, the power should be turned off.  

(6) Infants and people who cannot take care of themselves should not use electric blankets alone. They should be accompanied by other people.  

(7) Do not place sharp objects on the electric blanket, let alone put the electric blanket on prominent metal objects or other sharp objects for use.  

V. Electric blanket ex-factory sampling inspection items  

1. Ex-factory inspection items, requirements and methods:  

2. For ex-factory sampling inspection items, the sampling shall adopt GB/T2828.1, and the inspection lot size, qualified quality level and sampling scheme shall be determined by the manufacturer.  

3. Type test:  

1. Type test shall include all items stipulated in QB/ T2994-2008 and GB4706.8.  

2. GB/T2829 is used for sampling of type test  

QB/ T2994-2008 Inspection items:  

1. Appearance;  

2, size and shape error;  

3. Length of power cord and connecting flexible cord;  

4. Electromagnetic radiation;  

5. Temperature rise and its uniformity;  

6. Control device;  

7. Cleaning;  

8. Safe service life.  

Gb4706.8-2008 inspection items:  

1. Signs and instructions; 2. Protection against touching live parts;  

3. Start electric appliances; 4, input power and current;  

5, fever; 6. Leakage current and electrical strength at working temperature;  

7. Transient overvoltage; 8, wet resistance;  

9. Leakage current and electrical strength; 10. Overload protection of transformers and related circuits;  

11. Durability; 12. Abnormal work;  

13. Stability and mechanical hazards; 14. Mechanical strength;  

15. Structure; 16. Internal wiring;  

17. Components; 18. Power supply connection and external flexible cable;  

19. Grounding measures; 20. Screws and connections;  

21. Electrical clearance, creepage distance and solid insulation; 22, heat and fire resistance;  

23, rust prevention; 24. Radiation, toxicity and similar hazards.  

A -- Release cone; B -- cone spring; C -- release rod; D -- release mechanism; E -- Release the grip; F - hammer head; G - hammer spring; H - hammer rod; I - Handle  

A -- the base; B - arm; C -- loose fit shaft; D -- tapered refueling hole; E -- mechanical washer; F -- positioning screw plug; G - arm bracket; H -- rubber stop; I - slot; J -- sample; K -- cardboard; L -- anvil; M -- Two staples