摘要 |
A method and apparatus is described for improving the weighing accuracy of sensitive automatic balances when weighing heated substances. This is accomplished by substantially eliminating or reducing convection currents from interfering with and fluctuating the weight being sensed. An air barrier shield is used to cover the balance plate without contacting or touching the balance, thereby eliminating convection air currents from interfering with the movement of the balance. The air barrier is permeable to microwave radiation and capable of absorbing moisture and other volitilized substances while being substantially impermeable to air currents. Glass fiber matting or padding is particularly useful for forming the air barrier enclosure. The invention is particularly applicable to analytical determinations which require microwave heating of the substance to remove volatiles and the requirement to accurately and sensitively weigh the substances while still hot using an electrical balance.
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