Patent ID: 8157100

Claim:
A screening apparatus usable in a wastewater treatment plant to remove impurities contained in wastewater, comprising: a. a frame, b. a screen panel attached to said frame and formed of i. screen bars having upper and lower ends and front and rear surfaces and said screen bars being arranged parallel to each other to have gaps ranging from 1 to 10 mm therebetween, and ii. upper and lower spacer bars extending transversely at the opposite ends respectively of said screen bars and coupled thereto, said screen panel having front and rear surfaces defined by said corresponding front and rear surfaces of said screen bars, c. a plurality of rakes movable along said front surfaces of said screen bars to rake impurities caught by said screen panel, d. a drive system attached to said frame to move said rakes, and e. an impurity guide attached to said frame adjacent upper end of said screen panel to receive said impurities raked off said screen panel, wherein, the lower end of each of said screen bars includes a notch being connectible with clearance to one of a plurality of fastening holes formed on said lower spacer bar, and wherein said upper end of each of the screen bars comprises a fastening part formed by bending a part of the upper end of the screen bar toward the rear surface of the screen bar which is inserted into a through hole formed in said impurity guide, such that the upper ends of the screen bars are prevented from interfering with the linear travel track of the rakes, and wherein said screen bars have medial portions between their opposite ends, said apparatus further comprising support bars positioned closely adjacent the rear surfaces of said screen bars at the medial portions thereof and oriented in a direction perpendicular to the screen bars to prevent the medial portions from sagging.