Decree No. 380 / 2006 Coll.
Order laying down requirements for drum water meters
Valid
Order
Effective from 01.10.2006
Text versions:
01.10.2006
02.08.2006
380
DECLARATION
of 11 July 2006
laying down requirements for drum water meters
The Ministry of Industry and Trade provides pursuant to Sections 6 (2), 9 (1) and 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll. and Act No. 137 / 2002 Coll.:
This decree sets out the requirements for drum water meters used for measuring the flow of water at a temperature up to 90 ° C (hereinafter referred to as "water meters'), the procedure for their type-approval and the procedure for verifying them. This Decree was notified in accordance with Directive 98 / 34 / EC of the European Parliament and of the Council of 22 June 1998 laying down a procedure for the provision of information in the field of technical standards and regulations and rules and of rules on information society services, as amended by Directive 98 / 48 / EC.
The terminology, the requirements for water meters, the type approval procedure and the verification procedure are set out in the Annex.
This Decree shall take effect on 1 October 2006.
Minister:
Ing. Urban v. r.
Annex to Decree No 380 / 2006 Coll.
1 TERMINOLOGY
1.1. The duration of the test is the duration of one measurement (time interval between the start and end of one measurement).
1.2 The ethalon vessel is the volume rate used to implement, store and reproduce the liquid volume unit and transfer it to other meters.
1.3. An etalon flow meter is a meter used to implement and reproduce a unit of elongated volume and to transfer the unit to other meters.
1.4 The mass method of testing is the method of detecting the relative error of the water meter at which the elongated volume is determined indirectly by measuring the mass of the water elongated and its density.
1.5 The nominal flow rate (Qn) is the flow rate at which the water meter must be able to operate in normal use under continuous and interrupted operating conditions without exceeding permitted relative errors.
1.6 The coefficient of extension k = 2 for normal (Gaussian) distribution means that the confidence interval corresponds to the confidence coefficient value of 0,95 (i.e. the actual value is likely to be 0,95 at the limits of the value of the expanded uncertainty).
1.7 The fixed start test method is a method of testing a water meter at which the counter state of the water meter is not changed at the time of start and end of measurement (the liquid in the water meter is at rest).
1.8 Uncertainty is an estimate assigned to the result of the measurement and characterising the interval of values that are claimed to be within it of the correct value.
1.9 The mass test method is the method of detecting the relative error of the water meter at which the elongated volume is determined by means of an etalon measuring vessel or according to an etalon measuring device.
1.10 The elongated volume (VE) is the total volume of water that passed through the water meter over a given period of time.
1.11 The flow rate (Q) is the amount of water that passes through the water meter per unit of time.
1.12. Relative water-meter error (delta) is the difference between the water-meter reading and the volume elongated relative to the volume flow expressed as a percentage.
1.13. The Water Meter Data (VV) is the volume value given as a difference in the Water Meter Counter Data at the beginning and end of the measurement.
1.14 The size of the water meter is given as the maximum flow rate Qmax in m3 / h.
1.15. The water meter is a device built into a closed pipe consisting of chambers of known volume and a mechanism driven by the flow of water, which are gradually filled with water and then emptied.
2 WATER REQUIREMENTS
2.1. METHOLOGICAL REQUIREMENTS
2.1.1 Allowed relative errors
The allowed relative error of the accuracy of the water meters is
(a) ± 1% of the measured value on initial verification;
(b) ± 2% of the measured value for subsequent verification.
2.2 TECHNICAL REQUIREMENTS
2.2.1. Construction
2.2.1.1 Materials
The water-meter shall be made of materials the characteristics of which correspond to the purpose for which it will be used and which are resistant to internal and external corrosion. Changes in water temperature from 0 ° C to 90 ° C shall not adversely affect it.
2.2.1.2 Sealing, temperature resistance
The water meter shall be able to withstand a continuous water temperature of 90 ° C for an unlimited period of time while maintaining the correct function, without release, leakage through walls and without permanent deformation.
2.2.1.3 Indicator
The indicator device shall allow easy and unambiguous reading of the volume of measured water expressed in cubic metres.
The cubic meter and its multiples are shown in black and the parts of the cubic meter are in red.
The optical height of the digits shall not be less than 4 mm.
The digital indicators shall show a vertical upward displacement of all digits. The shift of any digit shall be completed when the digits of the nearest lower decade change from 9 to 0.
Indicators with indicators shall be rotated clockwise. The value for each section of the scale in cubic metres shall be expressed as 10n, where n is a positive or negative integer or zero, thereby creating a system of consecutive decades. Data x1000 x100 x10 x1 x0,1 x0,01 x0,001 shall be displayed near each part of the scale.
The symbol of the unit m3 shall be displayed either on the code list or in the immediate vicinity of the digital indication.
The fastest rotating readable numbered element ("control element ') shall move continuously. Its part is considered to be a verification part of the scale.
The length of the scale verification panel shall not be less than 1 mm and shall not be greater than 5 mm.
2.2.1.4. Number of digits and value of scale verification panel
The indicator device shall be able to display the volume expressed in cubic metres without return to zero corresponding to at least 1999 hours of operation at nominal flow.
The value of the scale verification panel shall be 1 x 10n or 2 x 10n or 5 x 10n.
2.2.1.5. Conversion devices
The water-meter shall be equipped with a device by which the relationship between the volume indicated and the volume which it has actually escaped can be changed.
2.2.1.6 Additional equipment
The water meter may contain an impulse generating device provided that such equipment does not adversely affect its metrological characteristics.
2.2.2. Labels and marks
Watermeters shall bear a label bearing the following information:
(a) a business name or name, registered office and identification number, if the manufacturer is a legal person, name (s) and surname (s), or, where he has a business name, address of the place of business and identification number, if he is assigned, if the manufacturer is a natural person;
(b) size designation - Qmax [m3 / h],
(c) the volume of the drum corresponding to one speed - V [m3];
(d) maximum working pressure - pmax [kPa],
(e) maximum working temperature - tmax [° C],
(f) serial number, year of manufacture.
3 TYPE APPROVAL
3.1. Type-approval procedure
The documentation submitted (1) shall determine whether the water meter meets the technical requirements (paragraph 2.2). If these requirements are met, further tests shall be carried out.
3.1.1. Number of water meters tested
The applicant shall provide for testing one water-meter of each approved size. Depending on the course of the tests, the Czech Metrology Institute is entitled to request additional water meters from the applicant.
3.1.2. Test equipment
The test apparatus shall consist of:
(a) from a storage tank of a volume equal to at least twice the amount of liquid which passes through the water-meter at a maximum flow rate of 60 seconds;
(b) from a pump with a total transport quantity corresponding to the maximum flow rate of the water meter tested;
(c) from a height tank equipped with an overpass edge and a bulkhead separating the inlet and outlet of the tank;
(d) a supply line which must have a gradient such that the flowing water surpasses the resistance in that pipe and flows freely into the tested water meter;
(e) from a drain pipe which must have such a gradient and brightness that there is no overflow of the water meter (it is a pressure-free gauge),
(f) from the control valve in combination with a suitable flow meter for setting the test flow;
(g) from a measuring line with an internal diameter corresponding to the dimension of the flow section of the water meter with a maximum difference of 2 mm;
(h) the dividing point (s),
(i) from the control horizon;
(j) an etalon (an etalon vessel, a weight, an etalon flow meter) which must be able to measure the elongated amount of the test liquid with an uncertainty not exceeding 1 / 4 of the maximum permissible error of the test water meter;
(k) a thermometer with a range corresponding to the test liquid temperature with a measurement uncertainty of ± 0,5 ° C for the volumetric method of measurement and ± 0,1 ° C for the mass method of measurement;
(l) from the main cap, filter and other elements used to control the test equipment.
The test equipment shall be subjected to a regular functional test to be conducted in the form of a circular comparison.
3.1.3. Test procedure
Tests shall be carried out in the following order:
(a) accuracy test - determination of error curves depending on flow;
(b) an accelerated long-term stability test;
(c) leakage and resistance test at temperature load.
3.1.4. Correctness test
Accuracy test - determination of error curves according to flow shall be carried out at least at the following flows: Qmax, 0,5 Qmax and 0,1 Qmax.
The test time during the test shall be more than 10 times the time of opening (closing) of the main closure. at least 120 seconds.
The minimum test amount of the test fluid during the test shall be calculated according to the relation
Vmin = 400.s.vδdov where
δdov - holiday water meter error in%
v - value of the counter part in dm3
s - Readability of the piece, which is 0,5 when read visually
3.1.5 Accelerated long-term stability test
For long-term stability, the water-meter shall be tested for 100 hours at the nominal flow rate and 50 ° C. The water-meter errors before and after the test shall not differ by more than 0,5% and shall not exceed the permitted relative errors referred to in paragraph 2.1.1. If necessary, this test may be divided into intervals of at least six hours.
3.1.6 Tight and resistance test at temperature load
The test shall be carried out at the flow rate of Qmax and the temperature of the test fluid from (85 ± 5) ° C to a temperature up to 30 ° C within an interval of eight minutes with a break of one to two minutes. After 25 cycles, check for leakage, damage or blocking of the water-meter components.
3.2. Type-approval certificate
The particulars of the type-approval certificate shall be laid down in a separate legislative act (2).
4 VERIFICATION
4.1 The procedure for initial and subsequent verification of the water meter is identical.
4.1.1. Verification is carried out by the Czech Metrology Institute or by an authorized metrology centre on a specified test facility.
4.1.2 The organisation of the test room and the test equipment used shall be safe, reliable and shall enable the verification tests to be carried out when compliance with the requirements for the size of the relative error of the gauge referred to in paragraph 4.2.3 above.
4.1.3 Verification of water meters is carried out with cold water.
4.2 Tests
4.2.1 General
The testing of water meters shall consist of:
(a) external inspections;
(b) correctness tests.
4.2.2 External inspection
The external inspection shall check:
(a) whether the water meter is mechanically damaged;
(b) whether the legibility of the digits and scales of the indicator device is satisfactory;
(c) the legibility, accuracy and completeness of the inscriptions and marks on the water meter (paragraph 2.2.2).
Water meters which fail to pass this test shall not be excluded from further tests.
4.2.3. Correctness test
Test to detect relative error of the water meter
where
VV - indication of the water meter tested
VE - elongated volume in dm3
4.2.3.1 Methods of testing
Tests may be carried out according to the method of measuring the elongated amount of test fluid:
(a) by volume method; or
(b) by a mass method.
4.2.3.2 Test equipment
The tests shall be carried out on the test equipment referred to in paragraph 3.1.2.
4.2.3.3 Test conditions:
(a) the accuracy test shall be performed at Qmax and Qn flows (0,5 Qmax);
(c) the minimum duration of the test and the minimum amount of elongated test fluid during the test are specified in paragraph 3.1.4;
(c) the test flow rate may be changed by a maximum of 4% during the test.
4.2.4 Relative error detected
The relative error detected shall not exceed the interval limits
± (bc124; δmax bc124; - 2 bc124; in bc124;) [%] where:
δmax - biggest holiday error of the drum water meter (point 2.1.1)
u - relative standard combined measurement uncertainty
4.2.5 Measurement uncertainty
The relative standard combined measurement uncertainty may be:
for < ± 0,25 [%]
4.2.6 Labelling of verified meters
Water meters meeting the requirements laid down in this Decree shall be provided with an official mark (3).
1) Paragraph 1 (2) of Decree No. 262 / 2000 Coll., which ensures consistency and accuracy of measuring and measuring instruments, as amended by Decree No. 344 / 2002 Coll.
2) § 3 of Decree No. 262 / 2000 Coll.
3) § 6 of Decree No. 262 / 2000 Coll.
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Regulation Information
| Citation | Decree No. 380 / 2006 Coll., laying down requirements for drum water meters |
|---|---|
| Regulation Type | Order |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 02.08.2006 |
|---|---|
| Effective from | 01.10.2006 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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