Roots vacuum pump used in paper mill practical examples
Most small and medium mills, used mostly for low-speed small machine. For example, single-cylinder 1092 (twin) rotary machine, rotary cylinder machine 1575, 1575 short net-cylinder machine, multi-cylinder machine 1575 net long, multi-cylinder 1760 net long paper machine. The machine in the past mostly with matching pumps water ring vacuum pumps. With advances in technology for many reasons, such as energy conservation and environmental protection, in the last ten years, at home and abroad have been in the paper machine’s vacuum system, widely used in the Roots vacuum pumps, vacuum pumps specifications should of course with the paper papermaking machine specifications and types of paper and other related technology, the requirement to match, only to obtain satisfactory results.
Selection Roots vacuum in the vacuum system of the paper machine is based on the following reasons:
(1) the degree of vacuum pumping speed and paper dryness of the quantitative impact on different sheets of paper quantitatively different in different degrees of dry vacuum requirements. For example, when the quantitative 24g / m2, in order to get 13% of the dryness, the vacuum must be 160mmHg, similarly, when quantification of 30g / m2 and 65g / m2, to be respectively 15% and 20% dry, vacuum degree must respectively 200mmHg and 450mmHg. Since like this quantitative increases sheet thickness, in order to improve the wet strength of a wet paper sheet, it is necessary to increase its dryness.
(2) According to the papermaking process on the vacuum system requirements can be clearly seen from the operating characteristics of the four-leaf ZJ type roots vacuum pump, wet vacuum pump and the characteristic curve: the degree of vacuum in the range of 250 ~ 550mmHg, the cis horizontal, and its essence is suction of the pump remained unchanged.
(3) the use of Roots vacuum economic effect on the performance characteristics of Roots vacuum pump with water ring comparison was addressed in the previous section. About Roots pump and water pump in terms of economic and technological benefits and how? This is the paper industry is more concerned about. In practice mills, for example, set forth the following questions:
Roots vacuum pump capable of saving. Roots vacuum pump high efficiency, is not generally liquid ring vacuum pump comparison. It means it is in the high zone (vacuum within 100-200mmHg range) the amount of power consumed by pumping units (the so-called specific power) much lower than in the water ring pumps. The reason is that in the high zone of water ring vacuum pump sub 400mmHg degree range. In a similar plant machine wire section and felt the vacuum degree requirements are less than 400mmHg, thus supporting the use of vacuum pumps is the play of the pump’s strengths.