GB/T 43908-2024Fertigation equipment (English PDF)

1 Scope

The document specifies the product designation, technical requirements, inspection rules, marking, packaging, transport and storage of fertigation equipment, and describes the corresponding test methods.

It applies to the design, manufacture, installation and inspection of fertigation equipment fitted at the head of the pipe network for irrigation and fertilization of crops.

2 Normative references

GB/T 4208-2017 Degrees of protection provided by enclosure (IP code); GB/T 5667 Agricultural machinery - Production test method; GB/T 9254.1-2021 Information technology equipment, multimedia equipment and receivers - Electromagnetic compatibility - Part 1: Emission requirements; GB/T 9480 Agricultural and forestry tractors and machinery, lawn and garden power equipment - Operator's manuals, drafting rules; GB 10395.1 Agricultural and forestry machinery - Safety - Part 1: General; GB 10395.8 Agricultural and forestry tractors and machinery - Safety technical requirements - Part 8: Drainage and irrigation pumps and pump units; GB 10396 Agricultural and forestry tractors and machinery, lawn and garden power equipment - Safety signs and hazard pictorials - General principles.

GB/T 13306 Plates; GB/T 13384 General specifications for packing of mechanical and electrical products; GB/T 23821 Safety of machinery - Safety distances to prevent hazard zones being reached by upper and lower limbs; JB/T 5673-2015 Coating of agricultural and forestry tractors and implements - General specifications; JB/T 9832.2-1999 Agricultural and forestry tractors and implements - Paint film - Determination of adhesion - Cutting method.

Dated references apply in the edition cited; undated references apply in their latest edition, including any amendments.

3 Terms and definitions

3.1 fertigation equipment: equipment that, according to the needs of the crop, regulates and manages water and nutrients together and supplies the irrigation pipe network with water and fertilizer meeting the requirements of the crop. Note 1 states that fertigation equipment is generally made up of an irrigation pump, a variable frequency device, a fertilization device, a filtration device, a monitoring device and a control device. Note 2 states that by control mode the equipment is divided into automatic and manual, and that by the way the fertilization device is connected to the main irrigation line it is divided into bypass type and main line type.

3.2 maximum water-fertilizer flow rate: the maximum value of the water and fertilizer flow that the equipment can supply to meet the requirements of the crop under the normal operating condition specified by the manufacturer.

3.3 pressure loss: the difference between the pressure at the outlet of the irrigation pump on the main line and the pressure at the water and fertilizer outlet, under the normal operating condition specified by the manufacturer.

3.4 flow rate ratio of water-fertilizer: the ratio of the fertilizer solution flow of the fertilization device to the irrigation water and fertilizer flow. The example given reads: a fertilizer solution flow of 2 L/h and an irrigation water flow of 198 L/h give a water and fertilizer flow of 200 L/h, so the flow rate ratio is 1 to 100.

3.5 maximum fertilization flow rate: the maximum value of the fertilizer solution flow that the fertilization device can supply under the normal operating condition specified by the manufacturer.

3.6 uniformity in motion: the property whereby, with the water and fertilizer flow ratio set to a fixed value, automatic equipment adjusts the fertilizer solution flow of the fertilization device through the control device as the irrigation water flow changes, so that the equipment runs at a fixed water and fertilizer flow ratio within the permitted range of variation.

4 Product designation

The designation of fertigation equipment is made up of a classification code, a characteristic code and codes for the main parameters, in the form 8 SF, followed by three fields separated by hyphens.

Reading the designation from the front: 8 is the major classification code for drainage and irrigation machinery; SF is the minor classification code, the first letters of the pinyin of the words for water and fertilizer; the characteristic code is S for manual equipment and A for automatic equipment; the first numeric field is the maximum water and fertilizer flow rate in cubic metres per hour; the second numeric field is the maximum fertilization flow rate in litres per hour.

The worked example given reads: automatic fertigation equipment providing a maximum water and fertilizer flow rate of 15 cubic metres per hour and a maximum fertilization flow rate of 500 L/h is designated 8SFA-15-500.

5 Technical requirements

5.1.1 The equipment is to adopt the applicable safety requirements and measures of GB 10395.1 and GB 10395.8 and, following the design principles of GB 10395.1, is to reach an acceptable level of risk through adequate risk reduction measures.

5.1.2 Guards are to be fitted at exposed moving parts and other parts liable to injure people, and are to comply with GB 10395.1 and GB 10395.8. Safety distances for the upper and lower limbs reaching hazard zones are to comply with GB/T 23821.

5.1.3 Safety signs complying with GB 10396 are to be placed near parts that carry a residual risk in normal operation, and are to be reproduced in the operator's manual, which is to include safety precautions to remind the operator.

5.1.4 The equipment is to be fitted with a dedicated control box with reliable protective earthing, and the box is to keep water out. The equipment is to have earth leakage and overload protection devices and an emergency stop button. Electrical conductors are to be sleeved in insulation and fixed securely; the electrical equipment and all exposed conductive parts are to be connected to the protective earthing circuit, and with 500 V applied between the power circuit conductors and the protective earthing circuit the insulation resistance is to be not less than 20 megohm. The degree of protection of the enclosure is to be IP54 as defined in GB/T 4208-2017.

5.1.5 When failure protection is triggered, the equipment is to give an audible or visible alarm or an instant message.

5.1.6 The electromagnetic compatibility emission limits of the communication and control system are to comply with Annex A of GB/T 9254.1-2021.

5.2.1 All parts are to be used only after passing inspection, outsourced and bought-in parts having a certificate of conformity. All pipe fittings, filtration devices, fertilization devices, valves and irrigation pumps in contact with water, fertilizer solution or the water and fertilizer mixture are to be made of corrosion resistant stainless steel or of polyvinyl chloride (PVC) or polyethylene (PE) plastic.

5.2.2 The filtration accuracy of the filtration device is to be not coarser than 178 micrometres (80 mesh). Waste water from cleaning the filtration device is to be discharged separately or collected and treated centrally.

5.2.3 The enclosure and the pipework are to carry clear and durable markings of the direction of flow.

5.2.4 The operator's manual is to be prepared in accordance with GB/T 9480.

5.2.5 All parts and joints are to be reliably sealed, with no leakage of water, fertilizer solution or the water and fertilizer mixture. The pressure bearing capacity of the pipework is to be not less than 1.5 times the design pressure, and the accuracy class of the pressure gauges used is to be not lower than class 1.0.

5.2.6 The equipment is to have at least the following functions: monitoring of the main parameters, including irrigation water pressure, fertilizer solution flow, electrical conductivity (EC) and acidity or alkalinity (pH) of the water and fertilizer mixture; control of the irrigation time; alarm on EC and pH exceeding their limits; and, for automatic equipment, control of the water and fertilizer flow ratio and of the fertilization time.

5.3 Performance indexes. When the equipment runs at an ambient temperature of 5 degrees C to 40 degrees C, a relative humidity of 5 percent to 90 percent, an atmospheric pressure of 0.080 MPa to 0.106 MPa and a rated voltage of 220 V or 380 V, the performance indexes are to comply with Table 1. Table 1 lists fourteen items: maximum water and fertilizer flow rate in cubic metres per hour, not less than the value declared by the manufacturer; control deviation of the maximum water and fertilizer flow rate, not more than 5 percent; pressure loss in MPa, not more than the value declared by the manufacturer; maximum fertilization flow rate in litres per hour, not less than the value declared by the manufacturer; accuracy of EC control, not less than 90 percent; accuracy of pH control, not less than 90 percent; uniformity of EC control, not less than 85 percent; uniformity of pH control, not less than 85 percent; uniformity in motion of automatic equipment, within plus or minus 5 percent; rate of alarm on exceeding a limit, not less than 95 percent; rate of correct starting and stopping of the equipment, 100 percent; rate of correct valve control, 100 percent; mean time between failures, not less than 120 h; and availability, not less than 95 percent.

5.4.1 The appearance and thickness of the paint film are to comply with TQ-4-SC-DM of JB/T 5673-2015, and the adhesion of the paint film is to be not lower than grade 2 as defined in JB/T 9832.2-1999.

5.4.2 The equipment is to look clean and smooth, with no knocks, scratches or other mechanical damage on the surface; the weld surfaces of welded parts are to be free of pores, slag inclusions and burn-through.

6 Test methods

6.1.1 The equipment runs under the conditions of 5.3, with a supply voltage fluctuation of not more than plus or minus 5 percent; the test water is to be clean water at a temperature of 5 degrees C to 30 degrees C.

6.1.2 The fertilizer solution prepared for the test is to be at least twice the quantity used in the test, with an EC of 60 mS/cm plus or minus 0.5 mS/cm.

6.1.3 The acidic fertilizer solution prepared for the test is to be at least twice the quantity used in the test, with a pH of 3.0 plus or minus 0.1.

6.1.4 The instruments and equipment used are to have been verified or calibrated and to be within their period of validity. Their accuracy is to meet Table 2, which lists the parameter, the measuring range and the accuracy requirement: time, 0 h to 24 h, 1 s per day; temperature, 0 degrees C to 100 degrees C, 1 degree C; relative humidity, 0 percent to 100 percent, 5 percent; flow, 0 to 250 cubic metres per hour, class 0.5; pressure, 0 MPa to 1.6 MPa, class 0.4; insulation resistance, 0 to 500 megohm, class 10; pH, 2.0 to 12.0, class 0.1; EC, 0 mS/cm to 200 mS/cm, class 0.1.

6.2.1 For the safety requirements of 5.1.1 to 5.1.6 the inspection method follows the relevant provisions of GB 10395.1, GB 10395.8, GB/T 23821 and GB 10396. Safety signs and the drafting of the manual are checked visually, the number and position of the signs being checked against the operator's manual, and the signs are at the same time wiped for 15 s with a cloth soaked in petrol and examined for damage and curling. The other safety items are checked and measured one by one by visual inspection, by hand or with ordinary measuring tools.

6.2.2 The electromagnetic compatibility emission limits of the communication and control system are measured in accordance with Clause 6 of GB/T 9254.1-2021.

6.3.1 For the items of 5.2.1 to 5.2.4: parts, including bought-in and outsourced parts, are checked for the presence of test reports or certificates of conformity; the materials of the parts are checked against test reports and purchasing documents; the other items are checked one by one by visual inspection or with ordinary measuring tools.

6.3.2 After the equipment has been started and the pipework kept full of water, the inlet and outlet water valves are closed and the power supply is switched off; a pressure pump raises the pressure to 1.5 times the maximum irrigation water pressure of the equipment and holds it for 1 h, and the joints are examined for seepage.

6.3.3 During the tests of 6.4 to 6.12 the functions required by 5.2.6 are judged by visual inspection or by triggering them through deliberate adjustment.

6.4 With the irrigation pump running at its specified performance, the inlet and outlet valves are opened to their fullest and the valves of the fertilization device lines are adjusted so that the water and fertilizer flow ratio reaches the set value required by the crop; after 5 min of stable running the water and fertilizer flow at the outlet is measured every 3 min, five readings in all, and the maximum water and fertilizer flow rate is calculated by Formula (1) and its control deviation by Formula (2). The key gives the maximum water and fertilizer flow rate and each individual flowmeter reading in cubic metres per hour, the control deviation, and the set value of the maximum water and fertilizer flow rate in cubic metres per hour.

6.5 With the pump running at its specified performance and the flow ratio at the set value, after 5 min of stable running the readings of the pressure gauge at the pump outlet on the main line and of the gauge at the water and fertilizer outlet are taken at the same time every 3 min, five readings in all, and the pressure loss is calculated by Formula (3). The straight length of pipe before the measuring point is to be not less than five pipe diameters and after it not less than two pipe diameters. The key gives the pressure loss and the two gauge readings in MPa.

6.6 With the pump running at its specified performance and all valves of the suction lines of the fertilization device opened to their fullest, measurement starts after 5 min of stable running; the fertilizer solution flow of each suction line is measured every 3 min, five successive measurements being recorded, and the maximum fertilization flow rate is calculated by Formula (4) and Formula (5). The key gives the maximum fertilization flow rate at each measurement and the flow of each suction line in litres per hour, and the number of suction lines.

6.7 The water and fertilizer flow ratio of the automatic equipment is set to 1 to 50 and the irrigation water flow is set in turn to 80, 90, 100, 110 and 120 percent of the specified pump flow, the control device adjusting the fertilizer solution flow automatically in each case; after 5 min of stable running the five irrigation water flow values and the corresponding fertilizer solution flow values are measured, each irrigation water flow being measured five times at 3 min intervals, and the mean of the measured water and fertilizer flow ratio at each of the five settings is calculated by Formula (6). The uniformity in motion of the automatic equipment is then calculated by Formula (7).

6.8 The EC target value is set to 2.0 mS/cm; the equipment is started and brought to the normal running state specified by the manufacturer and, after 5 min of stable running, a sample of the water and fertilizer mixture is taken at the outlet once a minute, five samples in succession, and the EC is measured with a conductivity meter. The uniformity and accuracy of EC control are calculated by Formulas (8) to (11), whose key gives the mean EC, each measured EC value, the standard deviation of EC and the set EC value in millisiemens per centimetre, together with the uniformity and the accuracy of EC control.

6.9 The pH target value is set to 6.0; the same procedure is followed and the pH is measured with a pH meter. The uniformity and accuracy of pH control are calculated by Formulas (12) to (15), whose key gives the mean pH, each measured pH, the standard deviation of pH, and the uniformity and the accuracy of pH control, together with the set pH value.

6.10 Following the operating method given in the manufacturer's manual, with the equipment running stably in the normal state, each alarm parameter in turn is adjusted deliberately to its alarm value so as to trigger the alarm function. Each alarm parameter is repeated five times with an interval of 2 min, and the rate of alarm on exceeding a limit is calculated by Formula (16), whose key gives the rate, the number of successful alarms for each parameter, and the number of alarm parameters tested.

6.11 Following the manufacturer's manual, the equipment is started and stopped ten times each at intervals of 2 min, and the rate of correct starting and stopping is calculated by Formula (17), whose key gives the rate and the total number of correct starts and stops. For equipment with automatic or remote start and stop, the control parameters are set and the equipment is judged to have started or stopped correctly if it does so when the set value is reached.

6.12 Following the manufacturer's manual, each valve is opened and closed three times each at intervals of 2 min, and the rate of correct valve control is calculated by Formula (18), whose key gives the rate, the total number of correct valve openings and closings, and the number of valves fitted to the equipment. For valves with automatic or remote opening and closing, the control parameters are set and the valve is judged to open or close correctly if it does so when the set condition is reached.

6.13.1 Reliability is assessed by a time terminated test on two sample machines, each running for a total of 150 h, working normally according to the manufacturer's manual. The working condition, failures and repairs of the sample machines are to be recorded during the test, the test time being recorded to the minute. The classification of test time and the rules for counting and judging failures follow GB/T 5667. If a critical failure occurs during the reliability assessment, the mean time between failures and the availability are to be judged not acceptable.

6.13.2 The mean time between failures is calculated by Formula (19), whose key gives the mean time between failures in hours, the shift operating time during the reliability assessment in hours, and the total number of serious and ordinary failures of the sample machine during the assessment, one being used in place of zero where no failure occurred.

6.13.3 Availability is calculated by Formula (20), whose key gives the availability and the shift time spent clearing failures during the reliability assessment, in hours.

6.14 The appearance of the paint film is checked visually, the thickness is measured in accordance with JB/T 5673-2015 and the adhesion in accordance with JB/T 9832.2-1999.

7 Inspection rules

7.1.1 Each item of equipment is to pass inspection by the quality inspection department of the manufacturer and to leave the works with a certificate of product quality.

7.1.2 Each item of equipment is to undergo the delivery inspection items of Table 3 before leaving the works and to pass all of them. Items that fail may be repaired or adjusted and submitted for re-inspection; if the re-inspection also fails, the product is judged not acceptable.

7.2.1 Type inspection is required in any of the following cases: type approval of a new product and transfer of an established product to another works; a substantial change in structure, material or process after regular production that may affect the performance of the product; wear of tooling or moulds that may affect the performance of the product; resumption of production after a long stoppage; periodic inspection during volume production, generally once every two years; and a large difference between the result of a delivery inspection and the previous type inspection.

7.2.2 Sampling is random. When sampling at the manufacturer, the products are to be acceptable products manufactured, installed, accepted and delivered within the last 12 months, and the inspection batch is to be not less than 10 units; sampling at users and distributors is not subject to that limit. The sample is two units. From the sealing of the sample until the inspection work ends, no adjustment, repair or replacement is to be carried out other than the servicing and adjustment specified in the operator's manual.

7.2.3 The type inspection items are divided into classes A, B and C according to how much they affect product quality: class A for items with a major effect, class B for items with a considerable effect and class C for items with an ordinary effect, as set out in Table 3. Class A holds 4 items: safety requirements, maximum water and fertilizer flow rate, accuracy of EC control and accuracy of pH control. Class B holds 10 items: operator's manual, equipment functions, control deviation of the maximum water and fertilizer flow rate, pressure loss, maximum fertilization flow rate, uniformity of EC control, uniformity of pH control, uniformity in motion of automatic equipment, rate of alarm on exceeding a limit, and mean time between failures. Class C holds 15 items: inspection of parts and their certificates of conformity, materials of parts in contact with water or fertilizer, filtration accuracy of the filtration device, waste water from cleaning the filtration device, flow direction markings, sealing of parts and joints, pressure bearing capacity of the pipework and accuracy of the pressure gauges, availability, rate of correct starting and stopping, rate of correct valve control, appearance and thickness of the paint film, adhesion of the paint film, appearance quality of the equipment, welded parts, and the nameplate. Table 3 shows for each item the corresponding technical requirement clause, the corresponding test method clause, and whether it belongs to the delivery inspection and to the type inspection, a tick meaning that the item is to be inspected and a dash that it is not.

7.2.4 The sampling and judging scheme follows Table 4. The acceptance quality limit (AQL), the acceptance number (Ac) and the rejection number (Re) in that table are counted by the number of nonconforming items. Assessment is item by item and judgement is by class: if the number of nonconforming items of a class is less than or equal to the acceptance number, the batch is judged acceptable; if it is greater than or equal to the rejection number, the batch is judged not acceptable. Table 4 gives 4, 10 and 15 inspection items for classes A, B and C respectively, a sample size of 2, acceptance quality limits of 6.5, 25 and 40, and acceptance and rejection numbers of 0 and 1 for class A, 1 and 2 for class B and 2 and 3 for class C.

7.2.5 Where the ordering party carries out sampling inspection of product quality, this is done according to the contract, and the acceptance quality limit and the inspection batch are agreed between supplier and purchaser.

8 Marking, packaging, transport and storage

8.1 Each item of equipment is to carry a firmly fixed and legible product nameplate complying with GB/T 13306, showing at least: the name and address of the manufacturer; the product designation and name; the main technical parameters; the works serial number; the date of manufacture; and the number of the standard applied.

8.2 The trademark or mark of the manufacturer is to be shown in a conspicuous position on each item of equipment.

8.3 Packaging is to comply with GB/T 13384. Before packing, the product is to be wiped clean, all exposed metal surfaces are to be coated against water and damp, and the pipe connections to the outside are to be sealed against the entry of contaminants. When the equipment is dispatched, the necessary accessories, spare parts, loose tools and any parts that have to be removed for transport are to be packed and labelled by category, so that the equipment, together with the necessary spare parts, accessories and loose tools, is not damaged or lost in normal transport.

8.4 Equipment leaving the works is to be supplied with the complete set of spare parts, accessories and loose tools specified in the product technical documents, and each item of equipment is to be accompanied by at least: the operator's manual; the certificate of conformity; a list of the necessary spare parts, accessories and loose tools; and the packing list.

8.5 Transport is to comply with the rules for road, rail and water transport. During transport, loading and unloading the equipment is to be secured reliably against overturning, knocks and crushing, and protected against rain and damp.

8.6 The equipment is to be stored on level, dry and ventilated ground free of corrosive substances. Where it has to be stored in the open, measures are to be taken against wind, sun, rain, snow and impact, and attack by harmful substances is to be avoided.