/ Scale Verification - Key Issues

Verification of weights - the main aspects

The verification of the measuring instrument is thatThe metrological and other characteristics of certain objects and their similarity with passport data are checked. Such actions are carried out by specially designated persons in the designated premises, while using specialized equipment. These actions are called - verification scales.

Types of verification

  1. Primary verification is carried out at the time of the release of scales from production or after repair. Also, this procedure is carried out during import.
  2. Periodic verification is applied to those verification tools that have already been put into operation. It is held once a year.
  3. An extraordinary verification is applied when any technical damage occurs, also if the balance has been kept for a long time and then put into operation.
  4. Inspection verification is carried out during metrological supervision.

Scale Verification
State verification has the right to conductSpecialists from Federal agencies that deal with technical coordination and belong to state witnesses. In the case when measuring instruments meet all requirements, it is considered that they have passed the verification. If, as a result of verification, some malfunctions were identified, then instead of a passport a certificate is issued that the device is unfit for use. Such scales require repair or calibration. If the verification was successful, the owner retains the relevant certificate, and the stamp imprint remains on the verified scales.

Stages of bench scale weighting

In total, there are three stages.The first stage is to verify without applying the load. At this stage, it is checked how correctly the scales are installed, and how they react to the attempt to unbalance them. At the second stage, the verification is carried out using a weight, the mass of which is approximately 1/10 of the load from the largest weighing limit. Weights are usually placed in the center and on the sides, the readings should be equal to the mass of the weight. The third stage determines the accuracy with which the scales operate, taking into account the maximum load. In this case, the weight is set only in the center, while the sensitivity of the weight is not checked.

Weights calibration methods

Scale Calibration Technique
Scales are calibrated in two ways.The first is statistical. It provides for the measurement of the force applied to the sensors being tested and the specimen exposed. That is, this method is applied to both exemplary and verified scales. The disadvantage of this method of verification is that the results may be unreliable. Another disadvantage of this method is that the device being tested is not in use. Dynamic method of calibration of conveyor devices or devices of continuous action - weighing the control sample. The disadvantage of this method is that this process is very laborious, while the result of verification will be inaccurate. Products that will be weighed must be in the bunker, which is physically unrealistic to perform. Samples of scales must also be present, which is not always possible. With this method, the scales will not be operated according to the staffing table.

Electronic balance

verification of frequency
Verification of electronic scales includesseveral stages of work: the study and testing of the device, the identification of metrological parameters, the measurement of the inconstancy of weights that are not subjected to stress. This also includes the recognition of the error of the readings of the device being tested, the sensitivity of the scales. If the scales have not passed the appropriate calibration, they are not allowed to be used.

Scale verification (frequency of this procedure isonce a year) is carried out in accordance with the legislative documents “On Metrology and Metrological Activities”. All scales in service shall be subject to periodic verification.

Scale Calibration Technique

Verification of electronic scales

The documents on the operation of the scales spelled outconditions that must be strictly followed. When the scales are being calibrated, the temperature, humidity, and atmospheric pressure must clearly correspond to the working indicator. During an external inspection, the absence of cracks and corrosion is usually established; all control items must be in their places, according to the operating documents. If it is a crane device, then in the passport there should be a certificate of its strength testing of the crane hook. At the time of testing the scales, it is necessary to identify how good they are, whether the control apparatus is not overloaded. During the determination of metrological boundaries, the inconstancy of the readings of the scales is checked in the absence of any loads. Metrological boundaries are calculated using the weights of the 4th digit. If the results of verification turned out to be positive, then this is noted in the passport and a stamp is made on the scales, which indicates the suitability of the scales for use. If the result of verification is negative, then the scales are not applied.