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GB/T 36865-2018Grain and oil machinery - Screw conveyor (English PDF)

粮油机械螺旋输送机

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

September 17, 2018

Implementation date

April 1, 2019

Scope

GB/T 36865-2018 is the English-translated version of 粮油机械螺旋输送机.

China's national standard for the screw conveyors used to move grain and other powdery or granular products through mills, silos and processing plants. A screw conveyor is a helical flight turning inside a trough - the Archimedes screw with a motor on it - and it survives in modern plant because it does what a belt cannot: the material travels inside a closed casing, so dust stays in and contamination stays out, the flow can be metered by shaft speed, and the machine takes up almost no floor space. In a grain plant those virtues come with a specific cost, because grain is fragile and a screw drags it against the trough wall; broken kernels lose value, generate dust and spoil faster, so this standard puts a ceiling on the breakage the machine is allowed to add. Around that it fixes the things that decide whether a conveyor works and keeps working: a series of ten basic models from 100 mm to 800 mm of screw diameter with their matching pitches and speed ranges, the thickness of the flight, the tolerances on screw diameter and pitch, and the clearance between flight and trough - too tight and the machine seizes on a stone, too loose and it stops conveying. It also settles the shaft materials and the way the flights are welded to them, the straightness and roundness of the casing, bearing seals that must not leak oil into the product, a limit on bearing temperature rise and one on noise, and it requires that the screw and the intermediate hangers can be serviced without dismantling the drive. Materials in contact with the product must not contaminate it, and guards and warning signs are required at exposed rotating parts and at the inlet and outlet openings. Capacity and drive power are calculated from formulas given in an annex and the model designation follows a code set in another, so that a purchaser can specify a machine and a supplier quote one without ambiguity.

Document preview — GB/T 36865-2018

National Standard of the People's Republic of China

ICS: 67.260
Classification: X 91

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

1 Scope
2 Normative references
3 Terms and definitions
4 Working principle
5 Models and basic parameters
5.1 Method of composing the model designation
5.2 Basic models of screw conveyors
5.3 Basic parameters of screw conveyors
6 Technical requirements
6.1 General requirements
6.2 Mechanical requirements
6.3 Requirements for process performance
6.4 Safety requirements
6.5 Hygiene requirements
7 Test methods
7.1 Inspection of bought-in parts
7.2 Inspection of the quality of the paintwork
8 Inspection rules
9 Marking, packaging, transport and storage

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard was proposed by the National Food and Strategic Reserves Administration and is under the jurisdiction of the National Technical Committee on Grain and Oil Standardization (SAC/TC 270).

The standard was issued on 17 September 2018 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and has been in force since 1 April 2019.

1 Scope

This standard specifies the terms and definitions, the working principle, the models and basic parameters, the technical requirements, the test methods, the inspection rules and the requirements for marking, packaging, transport and storage of screw conveyors.

This standard applies to screw conveyors whose working position is horizontal or close to horizontal, with an angle of inclination not greater than 20 degrees, and which convey powdery or granular grain continuously and evenly.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition, including all amendments, applies.

GB/T 191 Packaging - Pictorial marking for handling of goods

GB 2894 Safety signs and guideline for the use of them

GB/T 3768 Acoustics - Determination of sound power levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane

GB/T 5210 Paints and varnishes - Pull-off test for adhesion

GB 5226.1 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements

GB/T 13306 Plates

GB/T 24854 Grain and oil machinery - General specification for product packaging

GB/T 24855 Grain and oil machinery - General specification for assembly

GB/T 24856 Grain and oil machinery - General specification for castings

GB/T 24857 Grain and oil machinery - General specification for plate and plate-type steel members

GB/T 25218 Grain and oil machinery - General specification for product coating

3 Terms and definitions

The following terms and definitions apply to this document.

3.1 screw conveyor - a machine that conveys granular or powdery material by means of a rotating helical flight.

3.2 capacity - the mass of material conveyed in unit time.

3.3 rotational speed of screw - the number of revolutions of the screw in unit time.

3.4 diameter of screw - the projection of the helical flight and the screw shaft on a vertical plane.

3.5 pitch of screws - the axial distance between the corresponding points of two adjacent turns of the helical flight, measured on the mean diameter line.

3.6 angle of inclination - the acute angle formed between the longitudinal centre line of the screw conveyor and the horizontal plane.

3.7 filling coefficient - the coefficient expressing the degree to which the trough of the screw conveyor is filled with material.

4 Working principle

A screw conveyor is generally made up of a trough, the helical flight, the screw shaft, the end bearings, the intermediate hanger bearings and the drive unit. The helical flight is fixed to the screw shaft; the shaft is supported by the bearings at its two ends and by the intermediate hanger bearings, and is turned by the drive unit. The material enters the trough through the inlet and, pushed by the rotating helical flight, moves along the trough in the axial direction until it is discharged at the outlet.

5.1 Method of composing the model designation

The model designation is composed in accordance with Annex A.

5.2 Basic models of screw conveyors

The basic structure of the screw conveyor is shown in Figure 1, in which S is the pitch and D is the screw diameter, and the basic models are listed in Table 1.

Table 1 gives ten basic models. Model TLSS100: screw diameter 100 mm, pitch 100 mm, rotational speed 71 to 140 r/min. TLSS125: diameter 125 mm, pitch 125 mm, 63 to 125 r/min. TLSS160: diameter 160 mm, pitch 160 mm, 56 to 112 r/min. TLSS200: diameter 200 mm, pitch 200 mm, 50 to 100 r/min. TLSS250: diameter 250 mm, pitch 250 mm, 45 to 90 r/min. TLSS315: diameter 315 mm, pitch 315 mm, 40 to 80 r/min. TLSS400: diameter 400 mm, pitch 355 mm, 36 to 71 r/min. TLSS500: diameter 500 mm, pitch 400 mm, 32 to 63 r/min. TLSS630: diameter 630 mm, pitch 450 mm, 25 to 50 r/min. TLSS800: diameter 800 mm, pitch 500 mm, 20 to 40 r/min.

5.3 Basic parameters of screw conveyors

The capacity and the drive power of the screw conveyor are calculated in accordance with B.1 and B.2 of Annex B respectively.

6.1 General requirements

6.1.1 The product shall comply with the requirements of this standard and shall be manufactured in accordance with drawings and technical documents approved through the prescribed procedure.

6.1.2 Raw materials, bought-in parts and parts supplied by outside partners shall carry a certificate of conformity and may be used only after they have been inspected and found acceptable.

6.1.3 Plate parts and plate-type steel members shall comply with GB/T 24857.

6.1.4 Castings shall comply with GB/T 24856.

6.1.5 Assembly shall comply with GB/T 24855.

6.1.6 The coating of the product shall comply with GB/T 25218.

6.1.7 All welds shall be uniform and firm and shall be free from cracks, gas pores, slag inclusions, missed welds, burn-through, false welds and similar defects.

6.1.8 The installation and acceptance of the product shall be carried out in accordance with the instruction manual and the relevant regulations.

6.2 Mechanical requirements

6.2.1 The thickness of the helical flight shall comply with Table 2: 2.0 mm to 2.5 mm for a screw diameter of 100 mm; 2.5 mm to 3.0 mm for 125 mm and 160 mm; 3.0 mm to 3.5 mm for 200 mm and 250 mm; 4.0 mm to 5.0 mm for 315 mm to 630 mm; and 5.0 mm to 6.0 mm for 800 mm.

6.2.2 The screw shaft shall be made of low carbon round steel, medium carbon round steel, cold drawn round steel, seamless steel tube or straight-seam electric welded steel tube. A shaft shorter than 2 m and smaller than 38 mm in diameter should be made of round steel or cold drawn round steel; a shaft of 2 m or more in length and 38 mm or more in diameter shall be made of seamless steel tube or straight-seam electric welded steel tube.

6.2.3 The tolerance on the screw diameter shall comply with Table 3: plus or minus 0.8 mm for a diameter of 100 mm; plus or minus 1.2 mm from 125 mm to 400 mm; and plus or minus 2.0 mm from 500 mm to 800 mm.

6.2.4 The tolerance on the screw pitch shall comply with Table 4: plus or minus 3.0 mm for pitches of 100 mm to 250 mm; plus or minus 4.0 mm for 315 mm to 500 mm; and plus or minus 6.0 mm for 560 mm to 630 mm.

6.2.5 The clearance between the outside diameter of the screw and the trough shall comply with Table 5. For a screw diameter of 100 mm the maximum clearance is 7.50 mm and the minimum 3.75 mm; from 125 mm to 315 mm the maximum is 10.50 mm and the minimum 4.0 mm; for 400 mm and 500 mm the maximum is 12.50 mm and the minimum 4.25 mm; for 630 mm and 800 mm the maximum is 15.0 mm and the minimum 5.50 mm.

6.2.6 The straightness of the external surface of the conveyor casing shall be 1/1000; the roundness of the outside diameter, or the profile of the contour, shall be not greater than 2 mm; the external surface of the casing shall be smooth and any dishing shall be not greater than 2 mm; and the perpendicularity between the flange face of each casing section and the centre line of the casing shall be not greater than 2 degrees.

6.2.7 The local clearance between the helical flight and the screw shaft shall be not greater than 2 mm.

6.2.8 The helical flight shall be welded to the shaft by intermittent welds, laid on the non-working side or staggered alternately on the two sides. The end faces of the flight shall be welded on both sides. The size and the number of the welds shall comply with the product drawings and technical requirements.

6.2.9 The bearings shall be reliably sealed and there shall be no oil leakage.

6.2.10 The structure of the complete machine shall ensure that: a) the screw can be removed without moving or dismantling the drive unit; b) the intermediate bearings can be removed without moving or dismantling the screw; c) the intermediate bearings can be lubricated without removing the trough and the cover plate.

6.2.11 The product shall run smoothly, the helical flight shall not rub against the casing, there shall be no seizure and there shall be no abnormal noise.

6.2.12 When the product is run under no load the sound power level of the noise shall be not greater than 85 dB(A).

6.2.13 Under normal running conditions the temperature rise of the bearings, that is the difference between the working temperature and the ambient temperature, shall not exceed 40 degrees C, and the maximum temperature shall not exceed 75 degrees C.

6.3 Requirements for process performance

6.3.1 The capacity of the screw conveyor in normal operation shall meet the design requirement.

6.3.2 After the conveying operation has been completed, the increase in the breakage rate of the grain shall be not greater than 0.2 per cent.

6.4 Safety requirements

6.4.1 Safety warning signs shall be placed in a conspicuous position at those parts that are dangerous to the operator. The safety warning signs shall comply with GB 2894.

6.4.2 Guards shall be fitted to exposed rotating parts and to the inlet and outlet openings.

6.4.3 The electrical equipment shall be safe and reliable and its technical safety requirements shall comply with GB 5226.1.

6.5 Hygiene requirements

The materials used to make those parts of the machine that come into contact with the conveyed material shall not contaminate that material.

7.1 Inspection of bought-in parts

The certificates of conformity shall be checked.

7.2 Inspection of the quality of the paintwork

The thickness of the paint film shall be measured with a coating thickness gauge, and the adhesion of the paint film shall be tested in accordance with the requirements of GB/T 5210.

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 3768 Acoustics - Determination of sound power levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane · GB/T 5210 Paints and varnishes - Pull-off test for adhesion · GB 5226.1 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements

Cited by

GB/T 46744-2025Grain and oil machinery - Warehouse loading and unloading system

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