JJF 1591-2016Program of Pattern Evaluation of Coriolis Mass Flow Meters (English PDF)

5.1 Units of measurement

Flow meters shall use legal units of measurement.

5.2 Accuracy level

The accuracy level of the flow meter and its corresponding maximum allowable error shall meet the requirements of Table 1.If the accuracy level is not listed in Table 1, its maximum allowable error shall still meet the principle of corresponding accuracy level and maximum allowable error in Table 1.

Table 1 -- Accuracy level of flow meter

5.3 Sealed structure

For flow meters that are not allowed to be adjusted by the user, protective measures shall be in place. Any human interference that can affect the accuracy of the flow meter will leave a mark on the flow meter.

5.4 Installation marks

The flow meter shall have a clear and permanent flow direction mark.

5.5 Technical documents to be submitted by the applicant

The applicant shall provide two copies of the following technical documents.

- Application for "Type Approval of Measuring Instruments", commissioned by the government's metrology administration department;

- Product standards;

- Prototype photos and product structure photos and descriptions;

- Assembly drawings, circuit diagrams, and a list of key components;

- Instruction manual;

- Test reports prepared by the manufacturer or technical institution;

- Measuring instruments operating in explosive atmospheres shall provide explosion-proof certificates.

Technical documentation shall be complete, accurate, scientific, and reasonable. If any significant defects or deficiencies are found, the documentation and prototype shall be returned to the applicant for correction.

5.6 Test prototypes to be submitted by the applicant

5.6.1 For applications for a single product, three sample units shall be provided for flow meters with a diameter less than 100 mm. One sample unit shall be provided for flow meters with a diameter of 100 mm or more.

Accuracy level

Maximum allowable error /%

5.6.2 For applications submitted by product series, at least one-third of the

representative specifications from each product series shall be randomly selected. The number of test samples provided for each specification shall be based on the principle of a single product.

5.6.3 If the product uses key materials or components that are nominally the same but can affect the product's metrological performance, different prototypes shall be provided.

6.1 Maximum allowable error

The maximum allowable error of the flow meter shall comply with the provisions of

Clause 5.2.

6.2 Repeatability

The repeatability of the flow meter shall not exceed half of the absolute value of the allowable error specified in the corresponding accuracy level in Clause 5.2.

6.3 Zero stability

The ratio of the zero stability of the flow meter to the minimum flow rate shall not exceed 1/2 of the absolute value of the allowable error corresponding to the accuracy level.

6.4 Pressure loss

The pressure loss of the flow meter shall not exceed the specifications in the product instruction manual or product standard.

7.1 Accompany documents

The flow meter shall have an instruction manual. The instruction manual shall provide the flow meter name, model, measuring medium, working pressure range, working temperature range, nominal diameter, flow range, zero stability, accuracy level, power supply voltage, flow sensor material and weight, signal output method, manufacturer, explosion-proof rating and explosion-proof certificate number (for flammable and explosive environments), protection level, installation conditions and methods, and instructions for using the protection functions.

7.2 Appearance and nameplate

7.2.1 Appearance

Newly manufactured flow meters shall have a good appearance. The surface coating shall be uniform in color and free from burrs, scratches, cracks, rust, mildew, and peeling. Sealing surfaces shall be smooth and undamaged. Welded joints shall be smooth and clean, free from incomplete welds or detachment. Flow meter connectors must be secure and reliable, and shall not loosen or detach due to vibration. The numbers, text, and symbols displayed on the flow meter shall be clear and neat. The flow meter buttons shall have a comfortable feel and not be sticky.

7.2.2 Nameplate

The flow meter shall have a nameplate. The nameplate shall indicate the name, model, serial number, K coefficient, calibration factor, measuring medium (gas, liquid), flow range (qmin ~ qmax), nominal diameter, accuracy level, maximum working pressure, power supply voltage, flow sensor material, manufacturer and manufacturing date, manufacturing instrument license mark and number, explosion-proof rating (for flammable and explosive environments), and protection class.

7.3 Protection function

Flow meters with protection features shall have protection functions for flow meter parameters (such as passwords). If parameters are modified, the modification traces shall be left and permanently saved.

7.4 Protective function

For flow meters used in different applications, the corresponding protection level requirements specified in GB 4208 shall be met, and a protection level certificate issued by a nationally recognized institution shall be obtained.

7.5 Compressive strength

The flow meter shall be able to withstand 1.5 times the maximum working pressure for

5 min, and shall show no leakage, no damage, and no seepage.

7.6 Resistance to transportation and storage

The flow meter shall have good resistance to transportation and storage.

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