Pressboard

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

Cellulose Degradation and Transformer Fault Detection by the Application of Integrated Analyses of Gases and Low Molecular Weight Alcohols Dissolved in Mineral Oil

Abstract: This article presents a method for quantification of methanol and ethanol integrated in the same gas-chromatographic run with a quantification of gases dissolved in mineral oil, making it an integrated tool in transformer diagnostics. The results of aging experiments at 120 °C and 60 °C of Kraft paper, copper, barrier, and pressboard immersed in mineral oil, as well as the aging of thermal upgrade paper in mineral and natural ester oil at 140 °C are presented, in order to investigate correlations between different aging markers and to evaluate their partitioning between oil and cellulose at defined conditions. The results of partitioning experiments at 60 °C showed that re-absorption of methanol from oil to the cellulose materials is faster than the re-absorption of furans. This means that methanol is a paper-degradation marker that can be used in diagnostics over shorter equilibrium times and for the detection of developing faults at broader temperature ranges. Furthermore, a statistical overview of methanol concentration from a database and two transformer fault diagnostic cases are presented. Therefore, in addition to an analysis of gases dissolved in oil, the use of methanol and ethanol in transformer fault and failure investigations should be explored and verified through transformer fault investigations and postmortem analyses.

Experimental investigations on surface discharge characteristics over oil/pressboard interface based on a rod-to-plane electrode

Abstract: Partial discharge (PD) measurement and recognition is of great importance to assess the health condition of power transformers. Surface discharge is a typical PD event often happened within oil-paper insulation system. In this work, surface discharge over oil/pressboard interface is observed in laboratory using a digital PD measurement system. Accelerated aging experiment is performed to obtain aged oil and pressboards with different aging degrees. Then, the influences of insulation aging, electrode size as well as applied voltage on surface discharge characteristic are analyzed. Experimental results relevant to surface discharge measurements performed on lab-scale rod-to-plane electrode under different circumstances are presented with the purpose to spotlight surface discharge distributions aimed at identifying the basic nature of surface discharge over oil/pressboard interface. The obtained results would provide useful information to condition diagnosis of transformers.

Cosmetic packaging bag closing device

Abstract: The utility model discloses a cosmetic packaging bag closing device relates to cosmetics production processing technology field, including conveyer, base and closing device, conveyer is fixed in the base top, conveyer includes the alignment conveyer belt, seals conveyer belt and drive gear, the closing device includes hot pressboard and cooling device, the hot pressboard includes upper hot pressboard and upper hot -pressing plate, upper hot pressboard and upper hot -pressing plate are equipped with electromagnetic induction device from top to bottom respectively, cooling device includes salband and lower salband, go up the salband and pass through secondary drive gear connection driving motor, the salband lower part is equipped with the fan down, and this kind of cosmetic packaging bag closing device can carry out quick sealing to aluminum foil material through electromagnetic induction device to can realize automatic the alignment and the cooling, be worth promoting

Investigation of partial discharges in synthetic ester-pressboard under AC stress

Abstract: Pre-compressed pressboard was commonly used in power transformers along with mineral oil. Pressboard in combination with mineral oil is suitable composite insulation for oil filled transformers over several decades. Synthetic ester is a suitable alternative for mineral oil due to its biodegradable and fire resistant property. It is also compatible for transformer insulations as per recent research studies. Intent of this paper is to find out the suitability of synthetic ester as transformer insulation, with respect to partial discharge studies. Understanding partial discharge characteristics of synthetic ester with an influence of moisture, conducting particles and bubbles, the experimental study was carried out. Measurements of PDIV, PDEV, maximum apparent charges, and PRPD patterns were recorded in order to analyse the effect of various impurities over partial discharge activity. Oil moisture has more impact over board moisture.

Coir mat monolithic hot pressing production line

Abstract: The utility model discloses a coir mat monolithic hot pressing production line, including over -and -under type hot press unit, its characterized in that: including frame, pressure -bearing fixed plate, a plurality of hot pressboard and lift cylinder, be equipped with high temperature resistant conveyer belt and conveying belt drive device on the hot pressboard, high temperature resistant conveyerbelt pastes on the face of hot pressboard, moves when accomplishing the immigration of coir mat monolithic when high temperature resistant conveyer belt, and lift cylinder upwards promotes the hot pressboard, the hot pressboard rebound, and under pressure -bearing fixed plate and lift cylinder's effect, the coir mat monolithic on the hot pressboard is return by hot compression and fixation, liftcylinder, and the hot pressboard moves down by self gravity and restores to the throne, and the removal of the high temperature resistant conveyer belt of conveying belt drive device drive shifts outhot compression and fixation's coir mat monolithic. Because high temperature resistant conveyer belt has all been add to every hot pressboard among the over -and -under type hot press unit, can be conveniently with the immigration of coir mat monolithic with shift out, improved hot compression and fixation's work efficiency greatly.