Abstract: One or more hoses (10) belong to the ventilation system which through a perforation are constructed at least partially as ventilation hose (60). Each of the hoses is permanently connected with a number of holding devices distributed over its length, which hold the hose (10) from below. The holding devices run in a guide rail (14). The hose (10) is drawn into the empty or liquid-filled basin (10) with a traction device along the guide rail (14) which introduces the tractive force onto the body of the hose and holds it there without prestress.

Abstract: A water treatment module (14) has a sedimentation compartment (20), into which water is introduced under high pressure. A filter or microsieve (1) can be provided upstream of the sedimentation compartment (20). Above the sedimentation compartment (20) there is located a flooded first fixed bed reactor (22) for microbiological denitrification, which is flowed through from below. The water travels by way of an overflow device (34) and a sprinkler system (36) through which dissolved nitrogen is stripped and oxygen enrichment from the air occurs, into a second fixed bed reactor (38) for microbiological denitrification. This is constructed as a drip device, and is flowed through by air in a chimney-like fashion. Below the second fixed bed reactor (38) is located a catch basin (44) with a drain (54).

Abstract: Intensive fish fattening in open waters is increasingly disturbed by deposits of harmful substances. Fish fattening in artificial ponds is uneconomic because of the considerable outlay in terms of the fresh water and area required. These disadvantages can be overcome by a specially designed fish tank and a new process for operating such fish tanks. The fish tank (10) has, in its longitudinal center axis, a pit (11), into which a filler (31) with vertically extending flow channels (37) is placed. The fish water, together with an air/oxygen mixture, is circulated through these flow channels approximately 30 times per hour. The fish water is purified (nitrified) biologically according to the adhesive activated-sludge process by micro-organisms adhering to the filler. 50 to 500 liters of fresh water per kg of growing fish are added to the fish water, depending on the type of fish.

Abstract: Monitoring and signaling device having at least one tape for indicating a measurement value of a measuring unit and for actuating a signal transmitter, the tape having a section thereof stretched over spatially separated guides and having a travel proportional to the measurement value and a coating effecting actuation of the signal transmitter which is displaceable parallel to the section of the tape extending between the guides, including an indicator for indicating a set nominal-value signaling point, the indicator and the signal transmitter being integrated in a signal head, and two bars extending parallel to the section of the tape and carrying the signal head, the section of the tape being displaceable past the signal transmitter in direct vicinity thereof and between the signal transmitter and the indicator.

Abstract: In an indicating device for measuring and control apparatus, such as a pressure measuring device, having a planar scale, a flexible, endless indicator tape movable along the scale, at least two rotatable rigidly supported rolls tensionally supporting the tape, a pivotally mounted lever linkage connected at a point thereon to the tape, and means for rotating the lever linkage in an arcuate or circular movement at the connection point thereon in response to the measurement of a given physical parameter, means for compensating a lengthening of the tape caused by the arcuate movement of the lever linkage and tape at the connection point.