GB/T 44996-2024General technical requirements for bag forming, dosing and sealing machine of edible salt (English PDF)

1 Scope

This document defines the terms and definitions of the bag forming, dosing and sealing machine for edible salt, specifies the model designation, the basic parameters and working conditions, the technical requirements, the inspection rules and the nameplate, packing, transport and storage, and describes the corresponding test methods.

This document applies to the design, manufacture and inspection of bag forming, metering, dosing and sealing machines for edible salt, hereinafter called packaging machines.

3 Terms and definitions

3.1 bag forming, dosing and sealing machine of edible salt. A machine that automatically completes the operations of bag forming, metering of the edible salt, filling, sealing and cutting off.

3.2 finished product. The product obtained after bag forming, metering, filling, sealing and cutting off.

3.3 production capacity. The number of finished products completed per unit of time when the packaging machine is working normally.

3.4 qualified finished product rate. The percentage of the number of qualified finished products in the total number of finished products when the packaging machine is working normally.

4 Model designation, basic parameters and working conditions

4.1 Model designation. The model designation of the packaging machine shall be drawn up in accordance with GB/T 7311. Example: DXDY-R420/70 designates a bag forming, dosing and sealing machine for edible salt with a maximum film width of 420 mm, an output of 70 bags per minute and volumetric metering, of the first design.

4.2 Basic parameters. The names and units of the basic parameters of the packaging machine are: a) production capacity, in bags per minute; b) maximum film width, in millimetres; c) metering range, in grams; d) rated voltage and frequency, in volts and hertz; e) rated total power, in kilowatts; f) air consumption, in cubic metres per minute; g) reference overall dimensions, length by width by height in millimetres; h) reference mass of the complete machine, in kilograms.

4.3.1 The working ambient temperature shall be 5 degrees Celsius to 30 degrees Celsius, the relative humidity shall not be greater than 70 %, and the altitude shall not be greater than 1 000 m.

4.3.2 The deviation of the supply voltage from the rated voltage shall conform to 4.2 and 4.3 of GB/T 12325-2008.

4.3.3 The pressure of the compressed air supply shall be 0.6 MPa to 0.8 MPa. The quality of the compressed air shall conform to GB/T 13277.1-2023, with a particle class not lower than class 4, a humidity and liquid water class not lower than class 4, and a total oil content class not lower than class 3.

4.3.4 The packaging material in direct contact with the edible salt shall conform to the relevant national or industry standards, and composite film packaging material shall conform to GB/T 21302.

5 Technical requirements

5.1.1 The packaging machine shall be manufactured according to drawings and technical documents approved by the prescribed procedure.

5.1.2 The packaging machine shall run smoothly; the moving parts shall act sensitively, in coordination and accurately, without jamming and without abnormal heating, vibration or noise.

5.1.3 The pneumatic components and lines shall conform to GB/T 7932; the connections of the air lines shall be tight and free from leakage.

5.1.4 The heat-sealing temperature regulator shall allow the temperature to be adjusted within a certain range, the temperature set shall be stable, and a heating indication shall be provided.

5.2.1 Production capacity. The production capacity of the packaging machine shall reach the rated production capacity.

5.2.2 Temperature deviation on the surface of the heat-sealing part. The temperature deviation over the effective heat-sealing length on the surface of the heat-sealing part shall be within plus or minus 15 degrees Celsius.

5.2.3 Fill quantity and average actual content. The deviation of the fill quantity of edible salt shall conform to Table 1, and the average actual content shall conform to JJF 1070. Table 1 sets the permitted deviation of the fill quantity by category of edible salt, refined salt, low-sodium salt, crushed and washed salt and solar salt, across bands of declared net content; the table is broken up in the scan and the values cannot be assigned to the individual categories and bands with certainty, so no figures are reproduced here.

5.2.4.1 The seal of the finished product shall be flat, with clear impressions or embossing and without noticeable creases, scorching or pierced spots; the marking information on the finished product, such as the production date and the production batch number, shall be correct, clear and durable, and the printing position shall be consistent.

5.2.4.2 The dimensional errors of the finished product, see Figure 1, shall meet the following requirements: a) the overlap deviation of the longitudinal seal shall not be greater than 2 mm; b) the deviation of the centre position of the longitudinal seal shall not be greater than 2 mm; c) where the control method uses register mark positioning, the error of the cut-off position shall not exceed plus or minus 2 mm; where the bag length is controlled by other means, the error shall not exceed plus or minus 2 mm for a bag length less than 100 mm, and shall not exceed plus or minus 2 % of the bag length for a bag length of 100 mm or more.

5.2.4.3 The heat seal strength of the finished product shall conform to Table 2, which grades the requirement by the thickness R of the heat-sealing layer: for a thickness of 0.02 mm up to but not including 0.08 mm, not less than 10 N per 15 mm; for 0.08 mm up to but not including 0.18 mm, not less than 15 N per 15 mm; for 0.18 mm up to but not including 0.36 mm, not less than 50 N per 15 mm; and for 0.36 mm and above, not less than 70 N per 15 mm. Note: the material thickness in the table is the thickness of the heat-sealing layer material, the heat-sealed part mostly being made of a readily heat-sealable material.

5.2.4.4 After the drop test the seal of the finished product shall be intact and free from leakage.

5.2.4.5 The qualified finished product rate shall not be lower than 98 %.

5.2.5 Working noise. The working noise of the packaging machine shall not be greater than 80 dB(A).

5.3.1 The electrical control systems of the packaging machine shall conform to GB/T 5226.1-2019, shall be safe and reliable and shall act accurately; the wiring of each electrical device shall be securely connected and numbered; the operating buttons shall be responsive; the indicator lamps shall display normally. The packaging machine shall be fitted with an emergency stop device; once the emergency stop actuator has interrupted the subsequent commands, that command shall remain effective until it is reset. Resetting shall only be possible by manual operation at the position where the emergency command was initiated. Manual resetting of the emergency stop command shall not cause the packaging machine to restart automatically; restarting shall only be possible by the normal operating action.

5.3.2 The insulation resistance measured between the power circuit conductors and the protective bonding circuit of the packaging machine with 500 V DC applied shall not be less than 1 megohm.

5.3.3 The packaging machine shall have a reliable earthing device with a clear earthing mark. All exposed conductive parts shall be connected to the protective bonding circuit as required by 8.2 of GB/T 5226.1-2019. The connection between the earthing terminal or earthing contact and the earthed metal part shall have a low resistance, not exceeding 0.1 ohm.

5.3.4 The power circuit conductors and the protective bonding circuit of the packaging machine shall withstand a dielectric voltage test lasting at least 1 s.

5.3.5 The degree of protection of the enclosure of the electrical control cabinet shall not be lower than IP54 as given in GB/T 4208-2017.

5.3.6 To ensure the safety of persons and of production, control units involving safety shall use a safety circuit. In principle the safety control circuit shall use a safety voltage not greater than 36 V.

5.4.1 The safety protection of the packaging machine shall conform to JB 7233.

5.4.2 The safety protection design of the packaging machine shall conform to GB/T 15706.

5.4.3 Where the gears, belts, chains, friction wheels and other moving parts of the packaging machine are exposed, guards shall be fitted, designed in accordance with GB/T 8196. Reciprocating movements shall have limiting devices at their end positions, and the safety distances shall conform to GB/T 23821.

5.4.4 Protective measures shall be taken for the cutting and heat-sealing devices of the packaging material, such as guards interlocked with the drive mechanism and heat shields, designed in accordance with GB/T 8196 and with safety distances conforming to GB/T 23821.

5.4.5 Movable guards on the packaging machine shall be provided with interlocking devices safeguarding personnel, designed in accordance with GB/T 18831, and the safety-related parts of their control system shall be designed in accordance with GB/T 16855.1. When the operator opens a guard the packaging machine shall give an alarm and stop working.

5.4.6 When packaging material or edible salt runs short, the machine shall give an alarm automatically and stop working.

5.4.7 The parts and the fasteners such as bolts and nuts on the packaging machine shall be fixed reliably and prevented from loosening, and shall not fall off through vibration.

5.4.8 The packaging machine shall carry clear and conspicuous markings for operation, lubrication, burn protection and pinch protection, and the safety signs shall conform to GB 2894.

5.5.1 The principles governing the materials, design, manufacture and configuration of the packaging machine shall conform to GB 16798.

5.5.2 The hygiene requirements for the mechanical design of the packaging machine shall conform to GB/T 19891.

5.5.3 The raw materials and the bought-in components used in the packaging machine shall have a certificate of quality conformity from the manufacturer; where there is no such certificate, they may only be put into use after being accepted as conforming to the relevant product standard.

5.5.4 The screws, bolts, nuts and other fasteners used on the packaging machine shall be of stainless steel.

5.5.5 The parts in direct contact with the edible salt shall be non-toxic, odourless, corrosion resistant, wear resistant and resistant to contamination; their surfaces shall be smooth and flat, non-absorbent and free from dead corners, and easy to clean or disinfect; welds shall be ground and polished, with no crevices where product can lodge, and the filling device shall not contaminate the edible salt.

5.5.6 The parts in direct contact with the edible salt shall have good machinability, good resistance to permeation and reliable tightness.

5.5.7 The surfaces of the packaging machine not in direct contact with the edible salt shall be made of material resistant to salt spray corrosion; a surface coating technique may be used, the coating shall adhere firmly, and it shall resist absorption and permeation.

5.5.8 Food-grade lubricating grease shall be used at the positions of the packaging machine that may come into contact with the edible salt; the food-grade lubricating grease shall conform to GB 15179.

5.6.1 The appearance quality of the packaging machine after machining and assembly shall conform to the relevant provisions of GB/T 14253.

5.6.2 The paint or plastic coating on the non-machined surfaces of the packaging machine shall be flat and smooth and of uniform colour, without noticeable defects such as scratches, soiling, runs or blistering.

5.6.3 The surfaces of exposed metal parts shall be of uniform colour, without defects such as blistering, delamination or corrosion.

5.6.4 The instructions for use of the packaging machine shall be drawn up in accordance with GB/T 9969.

6 Test methods

6.1 Test conditions. The test conditions shall conform to 4.3.

6.2.1 No-load running test. Every packaging machine shall be given a no-load running test after assembly; the continuous no-load running time shall not be less than 2 h, 1 h at low speed and 1 h at high speed, and the running condition of the machine shall be checked.

6.2.2 Checking the tightness of the air lines. Soapy water or detergent solution is applied to the seals of the pneumatic components and to the line connections, and these are checked for leakage.

6.3.1 Production capacity test. With the packaging machine working normally, packaging is run continuously at the rated production capacity for 30 min, the number of finished products is counted and the production capacity is calculated by Formula (1), where V is the production capacity in bags per minute, M is the total number of finished products completed, in bags, and T is the actual running time, in minutes.

6.3.2 Temperature control test. The temperature regulator is set to the heat-sealing temperature value and a temperature meter, of accuracy plus or minus 1.5 degrees Celsius and resolution 0.1 degrees Celsius, is used to measure three points over the effective length of the heat-sealing part, one of them at the mid-point and the other two each 15 mm from the ends of the effective heat-sealing length; the temperature difference between the three points is measured.

6.3.3 Fill quantity deviation test. An electronic balance of accuracy 0.01 g is prepared, samples are taken according to Table 3 and the fill quantity of edible salt is weighed. Table 3 gives the sampling plan for metrological inspection, relating the inspection lot size to the sample size, the correction value for the average actual content, and the numbers of T1 and T2 shortfall items permitted; the columns of the table are broken up in the scan and the values cannot be matched to the lot sizes with certainty, so no figures are reproduced here. The average actual content is calculated by Formula (2) and the standard deviation of the actual content by Formula (3), and the average actual content is then compared with the declared net content minus the correction value F times s for the average actual content. In these formulas q is the average actual content of the samples, qi is the measured fill quantity of an individual bag of edible salt, n is the number of bags sampled and s is the standard deviation of the actual content of the samples.

6.3.4.1 Appearance quality check. After the packaging machine has been working normally and continuously and is running at its rated speed, 100 bags of samples are taken in three lots, with an interval of not less than 1 min between lots. The appearance quality of the 100 sample bags is checked visually and the number of non-conforming items a1 is counted.

6.3.4.2 Finished product dimensional error test. Thirty bags of samples that have passed the appearance quality check are taken and the dimensional errors of the finished product are measured with a steel rule of accuracy 0.5 mm; the number of non-conforming items a2 is counted. The register mark cut-off position is measured as follows: the relative distance between the register mark and the edge of the seal is measured on each bag, as shown in Figure 2; the average of the 30 bags is calculated; and the differences between the largest and the smallest of the 30 measured values and the average are taken as the register mark cut-off position error of the finished product.

6.3.4.3 Heat seal strength test. Thirty bags of samples that have passed the appearance quality check are taken and one test piece is cut from the left, the middle and the right of the seal of each bag. Each test piece is 15 mm wide and 50 mm long in the direction perpendicular to the length of the seal, excluding the sealed part, giving a length of 100 mm when flattened out through 180 degrees. The two ends of the test piece, with the seal in the middle, are placed in the grips of the testing machine. The grip separation is 50 mm and the test speed is 300 mm per minute plus or minus 20 mm per minute. The maximum load at rupture of the test piece is read, the lowest of the loads at rupture of the test pieces from a bag is taken as the heat seal strength of that finished product, and the number of non-conforming items a3 is counted.

6.3.4.4 Drop test. The remaining samples that have passed the appearance quality check are used for the drop test. The sample bag is dropped freely from a height of 1 m with the seal facing downwards and perpendicular to the impact surface; the seal is then checked and the number of non-conforming items a4 is counted.

6.3.4.5 Qualified finished product rate. The qualified finished product rate is calculated by Formula (4), where K is the qualified finished product rate and a1, a2, a3 and a4 are respectively the numbers of bags failing the appearance quality check, the dimensional error test, the heat seal strength test and the drop test.

6.3.5 Noise measurement. During continuous working, the noise of the packaging machine is measured by the method specified in JB/T 7232.

6.4.1 The insulation resistance is measured with an insulation resistance tester in accordance with 18.3 of GB/T 5226.1-2019.

6.4.2 With the electrical equipment disconnected from the supply, a constant current taken from a source of no-load voltage not exceeding 12 V, AC or DC, and equal to 1.5 times the rated current or to 25 A, whichever is the greater, is passed in turn between the earthing terminal and each accessible metal part. The voltage drop between the earthing terminal and each accessible metal part is measured and the resistance is calculated from the current and the voltage drop.

6.4.3 A dielectric voltage test is carried out with a withstand voltage tester in accordance with 18.4 of GB/T 5226.1-2019, the maximum test voltage being twice the rated supply voltage or 1 000 V, whichever is the greater.

6.4.4 The degree of protection of the enclosure of the electrical control cabinet is checked by the test method specified in GB/T 4208-2017.

6.5.1 The guarding, the interlocking protective devices at each position and the operating devices of the packaging machine are checked.

6.5.2 With the packaging machine running normally, a guard is opened and it is observed whether the machine gives an alarm and stops working.

6.5.3 With the packaging machine running normally, the packaged product is brought artificially to the lower control limit, or the packaging material is made artificially to run short, and it is observed whether the machine gives an alarm and stops working.

6.5.4 The anti-loosening measures on the fasteners of the moving parts and the limiting devices of the reciprocating mechanisms are checked.

6.5.5 The markings and signs at each position on the packaging machine are checked.

6.6.1 The material quality requirements of the packaging machine are checked against GB 16798 and GB/T 19891.

6.6.2 The certificates of quality conformity from the manufacturers of the raw materials and the bought-in components are checked.

6.7.1 The appearance quality of the packaging machine is checked visually.

6.7.2 The instructions for use of the packaging machine are checked against GB/T 9969.

7 Inspection rules

7.1 Classification of inspection. Inspection of the packaging machine is divided into delivery inspection and type inspection; the inspection items, requirements and inspection methods are given in Table 4. Table 4 lists twelve inspection items, from the electrical safety test to the check of the product nameplate and technical documents, and states for each whether it is compulsory for type inspection and for delivery inspection together with the requirement clause and the test method clause; the columns of the table are broken up in the scan and the marks cannot be assigned to the individual items with certainty, so the assignments are not reproduced here.

7.2 Delivery inspection. Every packaging machine shall be given a delivery inspection; the delivery inspection is passed when all its items conform, and the machine may only leave the works accompanied by a certificate of conformity.

7.3.1 Type inspection shall be carried out in any of the following cases: transfer of production of a product to another works, or trial manufacture and type approval of a new product; a substantial change in material, structure or process after series production has begun that may affect the performance of the packaging machine; periodically each year during normal production, or after a certain accumulated output; resumption of production after a long stoppage; a substantial difference between the result of a delivery inspection and that of the previous type inspection; a requirement for type inspection raised by the national market supervision authority.

7.3.2 Type inspection is carried out in accordance with Table 4. The type inspection is passed when all its items conform. If in the type inspection any one of the continuity of the protective bonding circuit, the insulation resistance or the dielectric voltage test within the electrical safety test fails, the type inspection is judged to have failed. Where other items fail, the packaging machine may be rectified and the failed items re-inspected after rectification; if items still fail after re-inspection, the packaging machine is judged to have failed the type inspection.

8 Nameplate, packing, transport and storage

8.1 Nameplate. A nameplate shall be fixed in a conspicuous position on the packaging machine; the dimensions and technical requirements of the nameplate shall conform to GB/T 13306. The nameplate shall show the following: the product model; the product name; the product standard, that is the number of this document; the main technical parameters of the product; the date of manufacture and the works serial number; the name of the manufacturer.

8.2.1 The transport packing of the packaging machine shall conform to GB/T 13384.

8.2.2 Before packing, the exposed machined surfaces of the packaging machine shall be given rust protection.

8.2.3 The packing case of the packaging machine shall be strong and reliable and suited to the demands of transport and handling.

8.2.4 The packing case shall have reliable protection against damp and rain.

8.2.5 The special tools and wearing parts supplied with the packaging machine shall be packed separately and fixed within the packing case.

8.2.6 The technical documents shall be properly packed and placed inside the packing case, and shall comprise: the product certificate of conformity; the instructions for use of the product; the packing list.

8.2.7 The outer surface of the packing case shall be marked clearly with the dispatch and transport handling marks, in accordance with GB/T 191.

8.3.1 The packaging machine shall be handled with care during transport and shall not be inverted or knocked.

8.3.2 The packaging machine shall be stored in a dry, ventilated place free from corrosive agents.