Livestock productivity depends not least on the temperature of the water that animals drink. Warm water is also required for farm needs. That’s why it’s so important to control its heating at any time of the year.
This can be entrusted to a simple automatic device. By the way, it will also take care of keeping the tank always full.
The reservoir (tank) must be metal and have reliable grounding. Level sensors VD1, VD2 and ND (see diagram) are made from pieces of insulated wire. Their length depends on the size of the tank, the maximum and minimum levels of its filling.
When toggle switch B2 is closed, the 220 V mains voltage is applied to the primary winding of step-down transformer Tr1 and to the coil of valve KK for water supply to the reservoir. Lamp L3 signals this. When the tank fills to sensor ND, the control circuit of thyristor T2 closes and lamp L4 turns on, signaling the water level in the tank. The liquid continues to fill the tank until it reaches sensors VD1 and VD2, installed at the same level. Thyristors T4 and T5 turn on, lamp L5, signaling that the water has reached the upper level, and relay P1. The latter, with its contacts P1/1 and P1/2, turns off KK and L3. Water supply stops.
When water is consumed, the control circuits of thyristors T4 and T5 are broken. But only T4 turns off (this is signaled by the extinguished lamp L5). Thyristor T5 remains on until the electrical circuit of sensor ND opens. Relay P1 turns on the coil of valve KK, and water begins to flow into the tank again.
The automatic device maintains the set water temperature in the range of 2—3°.
As Tr1, you can use a power transformer from any mains radio receiver or tape recorder. All windings except the mains winding are cut off, and new ones are wound instead with wire PEV 0.72—0.74, based on the fact that winding II is five-volt, and windings III, IV, V are twelve-volt. For example, if you use a transformer from the “Nota” tape recorder attachment, winding II should contain 33 turns, and windings III—V — 80 turns each.
The matching transformer Tr2 with a turn ratio of 1 : 1 can also be used ready-made from transistor radio receivers, for example VEF-12, VEF-201, “Gauja”, “Selga” and others. The homemade transformer has a Ш6Х6 core. Its two windings of 1000 turns each are wound with PEV 0.12 wire.
P1 — PE-21 relay for 12 V. Thermistor — MMT-4 for 3.9 kOhm. Fixed resistors — MLT, R3 — variable resistor SPO-1.
C1, C2 — electrolytic capacitors K50-3.
A. TSIULIN, technician
Recommend to read
A LOCOMOTIVE WITHOUT STEAM AND SMOKE
The first domestic locomotive ВЛ19. In the late 1920-ies in our country began the so-called industrialization, whose main objective was to lift the industry to the level of the leading...
DOUBLE PENCIL
If a wooden bar and drill two holes the diameter of pencils or flomasterom — get a new handy tool for drawing or sketching: one motion will be two parallel lines. Instead of a single bar...
