Section 46. The deputy director may, if he deems it desirable, and shall, upon request, test any weights, measures, instruments or mechanical devices of any kind used or intended to be used in standardizing the production of any manufactured article by controlling processes or by determining the dimensions, proportions or properties of materials or products, in determining wages or compensation for labor performed, in determining the dimensions or capacity of any tank, can or other container, or in determining the accuracy of any automatic weighing or measuring device. When any such weight, measure, instrument or mechanical device has been tested and found correct by the deputy director, he may seal the same. If he finds it inaccurate, he may, in his discretion, either condemn it or he may furnish the owner or user with a certificate indicating the amount and direction of any errors found by him. The deputy director may establish a suitable laboratory fee schedule for the testing of weights, measures, instruments or mechanical devices. This section shall not give to the said deputy director or to his inspectors the power to seal any of the devices which, on April twenty-ninth, nineteen hundred and twenty, were required by law to be sealed by the local sealers throughout the commonwealth.