Vízügyi Közlemények, 1973 (55. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(42) 3. Exposed levee sections are very difficult to protect adequately against wave action and severe damages may occur even in spite of tremendous flood fighting efforts Along the exposed levee sections wave action should desirably be solved by contemporary, durable measures which are not organically related to flood fighting measures. 4. For the successful reinforcement and heightening of the flood levees it is suggested to construct model sections adopting the "mixed type" cross-sections shown in Figs. 4 and 6 for strengthening work. BRIEF PUBLICATIONS AND REPORTS 1. Pálfai, Imre, Civ. Engr.: The area output of portable sprinkler equipment (For the Hungarian text see pp. 237) The area output of sprinkler equipment is controlled by three main factors, namely 1. the demand for irrigation water, 2. the daily operating hours and 3. the discharging capacity of the equipment. These factors arc found from the following formulae : The irrigation water demand: q = 0.1157 Y (1) where q = the continuous irrigation jet, in lit/sec. hectare units, /i = the total water quantity to be delivered in a single irrigation phase expressed as mm depth of water cover, X = the length of an irrigation phase in calendar days. The daily operating hours: t = k^

2t* (2) where t = average daily effective operating hours, t = daily operating hours progammed, A-^the percentage utilization of daily operating time, /f

2 = ratio of irrigation days to calendar days. The magnitude of k\ is expediently taken from 0.80 to 0.90, while the average value of /с, is 0.88 with no irrigation on Sundays. The discharge delivered by the equipment is 0 = ^*20* where Q = the effective discharge delivered by the equipment, in lit/sec units, Q* = the planned discharge of the sprinkler equipment in lit/sec units, = correction factors for wear of the pumping machine sets, «

2 = correction factor for increased head losses. The average values of and x.

2 are 0.85 to 0.95 and 0.9 to 1.00, respectively. With the above values the area output F in hectare units is Qt 24q illustrated in Fig. 2. 2. Csepregi, László, Mech, Engr. : Removal of debris from entrance canals (For the Hungarian text see pp. 241) On the entrance side of drainage pumping stations fixed racks have been used for retaining floating debris. With the increasing number and longer operating hours of pumping stations, the manual cleaning of racks and the head losses caused growing problems ( Fig. 1 ). The mechanical rack cleaning devices used at power stations proved too expensive for this purpose. The mechanically driven, self-cleaning moving racks developed by the author proved satisfactory in the exprimental installations (Figs. S and в

). Tire continuous rack field here consists of forks equipped with teeth, which move in operation upward with the peripheral speed of the driving pair of cog wheels (Fig. 4). As the forks reach the upper dead center, they tilt to the horizontal position and drop the accumulated and raised debris on a conveyor belt.