Pressboard

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

Paper folding mechanism

Abstract: PURPOSE:To improve the stack performance of paper to be folded onto a stacker table by reducing the friction factor of a pressboard in a vane of a stopper wheel and providing the paper pressing force to said pressboard through a resilient member. CONSTITUTION:When folding a paper 7, a positioning member 37 is rotated by predetermined amount in predetermined direction to position a stopper wheel 21 and a guideboard 22 at the position corresponding with the paper width and to rotate a rotary shaft 23 under this state thus to function a printer. Consequently, even if there is an inflated portion at the folding section (opposite upper end sections) of paper 7 to be discharged to the lower section upon completion of printing, said inflated portion is pressed and corrected by a pressboard to be energized through a resilient board provided on a vane 24 of the stopper wheel 21. Since the pressboard is made of low friction factor material, the paper 7 will never slip when pressing to perform folding reliably resulting in good stack performance.

A New Approach to Estimate Activation Energy of Oil-impregnated Pressboard Stressed under Switching Impulse at Different Temperatures

Abstract: This paper presents an advanced technique for calculating activation energy of oil-impregnated pressboard through dielectric response current measurement under switching impulse voltage at different temperatures. The proposed technique analyzes the measured impulse voltage and current signals to formulate its equivalent circuit at different temperatures. The equivalent circuit parameters are utilized to determine the shifting of ac conductivity curve along frequency axis with variations in temperatures. Based on the shifted ac conductivity curves at different temperatures, the corresponding activation energy of the insulation is estimated. The effectiveness of the proposed technique is investigated through a few laboratory prepared test samples.

Research on the variation of transformer pressboard's resistivity and permittivity with temperature and moisture

Abstract: The converter transformer is one of key equipment in the High Voltage Direct Current (HVDC) transmission system, the performance of the insulating pressboard in which can directly affect the quality of electric energy, and which could be affected significantly by the temperature and moisture. Therefore, an experimental platform was set up in this paper for the research on typical electrical parameters (mainly resistivity and permittivity) of the pressboard. The experiment results indicated that with the increase of temperature and moisture, the relative permittivity of the insulating pressboard increased gradually, and the largest increase on percentage could reach 185.9%. While at the same time, the resistivity gradually decreased, whose maximum decrease in the extent could reach 95.9%. And the properties of insulating pressboard in different manufacturers also showed significant difference. What was found in this paper could provide a reliable basis for the field evaluation of converter transformer and its optimization design.

The study on flow electrification of oil-cellulose insulating system in large power transformer

Abstract: Electrical breakdown due to charge accumulation from transformer oil flow has caused many failures of large power transformers world wide. The problem is due to the entrainment of diffused electrical double layer charges into circulating transformer oil. As the charges accumulate on the surface of solid insulating materials and in volume oil, static potential builds up. If the rate of charge accumulation is greater than the rate of charge relaxation, harmful spark discharge may occur. By employing a pressboard pipe model, the study carried out revealed the influence of higher oil flow rate and upstream charge on flow electrification By simulating an actual transformer internal structure, it is noticed that there is a probability of partial discharge inception under higher oil circulation velocity. However, the upstream charge and dry zone can lead to a great increase of electric field strength, which may become important potential causes of partial discharge inception under the condition of relative low oil velocity.

Machine for automatic steam ironing garment

Abstract: The utility model relates to a machine for automatic steam ironing garment, belonging to hot press equipment and comprising a machine body, a base, a rotating shaft, big extension springs, a workbench, an operating mechanism, a rotating mechanism, an electrical system, an air spraying mechanism, a temperature indicating lamp and a power switch. The utility model has the advantages that the temperature can be controlled automatically and accurately; the self control operation protective performance is provided; the running of the operating mechanism is stable; the pressure can be changed according to the thickness of clothing; a temperature regulator is arranged on a hot pressboard to satisfy the requirement of different clothing; the machine body is provided with the air spraying mechanism to spray the air to improve the effect of ironing; both the hot pressboard and the machine body and the workbench and the base are connected by the rotating mechanism to make the pressboard and an air board rotate by 90 DEG for the convenience of packaging, storing and transportation.