A thermostat is a device that allows you to maintain a stable temperature in a confined space. Used in bacteriological or virologic laboratories for cultivation of microorganisms at a certain temperature and in clinical laboratories for various chemical analyses.
Thermostats are water and air. Both thermostats are metallic Cabinet with the double walls (Fig. 1)between which is the fluid (air or water). Saving of heat is provided by a strip of the insulation material (asbestos fibre, cork, felts, and so on). In thermostats have an electric heater. In water circulators it is separated from the water with a metal casing. A necessary element of any thermostat is the thermostat (contact thermometer), due to which automatically turns on and off the heater and thus constant temperature of the thermostat.
Deviation from the specified temperature in the interval 28-39° is ±0,6 degrees. If you need a more stable temperature, use ultraterrestre (Fig. 2).
Ultraharmonic is a metal container with a lid, which are mounted heater, contact and control thermometers, holes with connections for input and output water, sunroof for entering the samples and the electric motor with a mixer. Temperature stability is achieved by vigorous mixing of the water (brine) by means of electric motors and automatic regulation with the help of the contact thermometer.

dry air thermostat TS-450
Fig. 1. Dry air thermostat TS-450: left - a General view; on the right - scheme. 1 - contact thermometer; 2 - body; 3 - shelf; 4 - working chamber; 5 - average Luggage; electric heater; 7 - heat-insulating material: 8 - stand; 9 - ground; 10 - toggle switch adjustment: 11 - cord for connection to the network; 12 - panel; 13 - outside the door; 14 - stick the outer door; 15 - inner door; 16 - constipation interior doors; 17 - casing: 18 - a reference thermometer.
ultraharmonic TC-15 M
Fig. 2. Ultraharmonic TC-15 M: 1 - contact thermometer; 2 - control thermometer; 3 - hatch with cover from the rings of the samples; 4, 5, 8 and 9 connections for input and output water; 6 - flexible coupling; 7 - holder; 10 - motor.