Pressboard

About: Pressboard is a research topic. Over the lifetime, 1123 publications have been published within this topic receiving 9089 citations.

Sell cabinet cargo discharging device

Abstract: The utility model discloses a sell cabinet cargo discharging device, lift the board after, including base, front pressboard, driving plate, link to each other with a supporting shaft between base andthe front pressboard, install the hinge torsional spring on the base, last a plurality of rotation connecting portion and the supporting shaft installation cover of being equipped with of front pressboard, front pressboard's top is equipped with a plurality of arcs and rolls up the head, connects with the cooperation of the 2nd supporting shaft between front pressboard and the driving plate, the driving plate is lifted after and can the dismantlement mode be connected between the board, is equipped with a plurality of the 2nd supporting shaft installation cover on the driving plate, after liftand install the goods stopper on the board. The utility model has the advantages of it is efficient that the messenger sells the shipment of cabinet, and the running cost is low, simple structure, and the dismouting is maintained conveniently.

Experimental Approach of Dielectric Losses Measurement in Insulating Paper under Distorted Voltage Stress

Abstract: The present work describes an experimental investigation dealing with the harmonic distortion of the voltage applied to samples of pressboard paper. The investigation especially concerns the study of dielectric losses in order to determine the contribution of each component in these losses. The influence of the moisture level of the samples is also discussed with respect to the influence of the humidity on the insulating system. A new method of determining the losses is proposed; it permits the weighing of the contribution of each harmonic. Three different power supplies with different distortion rates were used in this work. For each experiment, the form and the RMS value of the current and the voltage are reported. The harmonic analysis was carried out, and the results show an important effect of the distortion rate on the voltage and the moisture level on the dielectric losses.

Dielectric response change of pressboard immersed with mineral oil after replacing insulating liquid with synthetic ester

Abstract: The manufacturer of synthetic ester claims that replacing mineral oil with his product does not affect the work of the unit. Despite assurances, this information should be treated cautiously. Insulating liquid replacement, i.e. substitution of oil with ester, and especially intermediate stages of this process can cause problems while evaluating solid insulation moisture of the transformer done by means of the most commonly applied FDS indirect method. The article presents results of model investigations of the dielectric response of pressboard samples immersed with mineral oil, which was replaced with synthetic ester afterwards.

Analysis of the Impregnation Process of Cellulose Materials by Using Ester-Based Liquids and Mineral Oil

Abstract: Nowadays, new alternative of dielectric liquids with biodegradable characteristics has been considered to replace conventional mineral oil in both distribution and power transformer applications. However, there are some manufacturing processes that need to be modified to incorporate these ecological fluids, mainly in power transformers. Ester liquids, either natural or synthetic, show higher viscosity than mineral oil; therefore, a significant impact on the impregnation process of insulation materials is expected. In this work, the impregnation process of cellulose insulation is investigated by using three different liquids: natural ester (NE), synthetic ester (SE), and mineral oil. Laboratory tests were carried out using insulation blocks and pressboard samples to evaluate the influence of each fluid in the cellulose material. It is shown that the impregnation process with ester liquids is longer than mineral oil, at room temperature; however, it could be reduced by increasing the temperature of the ester liquid.

Investigation on Dynamic Diffusion Behavior of Furfural in Oil-Pressboard Insulation under Partial Oil Replacement Condition

Abstract: Furfural, as a typical chemical indicator, is used to evaluate the aging state of the cellulose insulation in the transformer. However, partial oil replacement will lead to the loss of furfural in oil and disturb the equilibrium distribution of furfural between oil and cellulose insulation, which could affect the evaluation results of the aging state of the cellulose insulation. Unfortunately, the influence of partial oil replacement has not been focused on. Given this issue, this work studies the influence of partial oil replacement on dynamic diffusion behavior of furfural in oil-pressboard insulation. First, the dynamic diffusion behavior of furfural between insulating pressboard and oil after partial oil replacement is discussed, and the theoretical diffusion model of furfural is established. Second, based on the mass gain curve of furfural in oil, the diffusion coefficients under different oil replacement ratios are obtained. Finally, a formula for calculating the diffusion equilibrium time is proposed. This paper attempts to report a method for analyzing the impact of the oil replacement ratio on the dynamic diffusion of furfural. These findings are expected to improve the accuracy of the aging assessment results by using furfural analysis.