【正文】 ign of chemical treatment operations involves not only the sizing of the various unit operations and processes but also the necessary appurtenances. Because of the corrosive nature of many of the chemicals used and the different forms in which they are available, special attention must be given to the design of chemical storage, feeding, piping, and control systems. 化學貯存 Scale Control 611 3 611 3 進料系統(tǒng) 611 3 固體進料 Dry Chemical Feed Systems A dry chemical feed system typically consists of a storage hopper, dry chemical feeder, a dissolving tank, and a pumped or gravity distribution system. The units are sized according to the volume of wastewater, treatment rate, and optimum length of time for chemical feeding and dissolving. Hoppers used with powdered chemicals that are pressible and can form an arch such as lime are equipped with positive agitators and a dust collection system. Dry chemical feeders are either of the volumetric or gravimetric type. In the volumetric type the volume of the dry chemical fed is measured, whereas in the gravimetric type the weight of chemical fed is measured. 611 3 With a dry feed system, the dissolving operation is critical. The capacity of the dissolving tank is based on the detention time, which is directly related to the wettability or rate of solution of the chemical. When the water supply is controlled for the purpose of forming a constant strength solution, mechanical mixers should be used. Depending on the flow pattern within the mixing tank, it may be necessary to add baffles for effective mixing. In smaller mixing tanks, the mixer can be set at an angle to avoid the use of baffles. Solutions or slurries are often stored after dissolving and discharged to the application point at metered rates by chemical feed pumps. 611 3 611 3 進料器類型 Typical characteristics of chemical feedersa 611 3 611 3 611 3 611 3 液體 進料 Liquid Chemical Feed Systems Liquid chemical feed systems typically include a solution storage tank, transfer pump, day tank for diluting the concentrated solution, and chemical feed pump for distribution to the application point. In general, liquid feed systems provide for better initial contact and dispersion of the chemical and the wastewater. The storage tank is sized based upon the stability of the chemical, feed rate requirements, regulatory requirements, delivery constraints, and availability of the supply. Spill or secondary containment is usually required around the storage tanks。 , March 22, 2023 ? 雨中黃葉樹，燈下白頭人。 :25:5901:25Mar2322Mar23 ? 1故人江海別，幾度隔山川。 :25:5901:25:59March 22, 2023 ? 1他鄉(xiāng)生白發(fā)，舊國見青山。 。 2023年 3月 22日星期三 1時 25分 59秒 01:25:5922 March 2023 ? 1做前，能夠環(huán)視四周；做時，你只能或者最好沿著以腳為起點的射線向前。 , March 22, 2023 ? 很多事情努力了未必有結果，但是不努力卻什么改變也沒有。 :25:5901:25Mar2322Mar23 ? 1世間成事，不求其絕對圓滿，留一份不足，可得無限完美。 :25:5901:25:59March 22, 2023 ? 1意志堅強的人能把世界放在手中像泥塊一樣任意揉捏。 。 2023年 3月 22日星期三 1時 25分 59秒 01:25:5922 March 2023 ? 1空山新雨后，天氣晚來秋。 , March 22, 2023 ? 閱讀一切好書如同和過去最杰出的人談話。 :25:5901:25Mar2322Mar23 ? 1越是無能的人，越喜歡挑剔別人的錯兒。勝人者有力，自勝者強。 2023年 3月 22日星期三 上午 1時 25分 59秒 01:25: ? 1最具挑戰(zhàn)性的挑戰(zhàn)莫過于提升自我。 2023年 3月 22日星期三 1時 25分 59秒 01:25:5922 March 2023 ? 1一個人即使已登上頂峰，也仍要自強不息