Solvent

SOLVENT. Solvent-naphtha-benzene-solvent represents a liquid fraction of coal tar light oil, obtained at t° 120-180°. The main component of solvent-naphtha is xylene (62-24%). Solvent-naphtha is slightly toxic, does not cause poisoning, does not irritate the kidneys; it is not explosive; its fire hazard is equal to that of kerosene. Solvents are also obtained from petroleum of various deposits. Solvent-naphtha is a transparent liquid, non-staining, with a pleasant odor; petroleum solvent is black-brown, not always transparent, with a sharp unpleasant odor, sometimes with significant toxicity. Lastochkin and others experimented with solvents (yellow and red-brown; whether these were solvent-naphtha or petroleum is not indicated) and established significant toxicity of the tested samples. According to Okunevsky's observations over 3 years on a large amount of material, mild poisonings in workers were observed only when working with certain petroleum solvents and, moreover, very rarely. The composition of solvents is not standardized, although their widespread use in sanitary practice requires this measure. Solvent-naphtha, which possesses energetic insecticidal action, is of the greatest value in sanitary terms. However, solvents obtained from petroleum rich in aromatic hydrocarbons also possess significant insecticidal properties. Solvent-naphtha and certain petroleum solvents exhibit insecticidal action on lice, bedbugs, fleas, and cockroaches. Cockroaches are the most resistant to solvents. Lice, when wetted in solvent-naphtha, die within 50 seconds, nits within 50 minutes. The insecticidal effect of solvent-naphtha and other solvents under conditions of wetting insects gave grounds to propose it in a mixture with soap and water in bathhouses and sanitary stations for treating the hairy parts of the bodies of lousy people for 20-30 minutes (soap-50 parts, water-200 parts, solvent-naphtha-250 parts, green soap-25 parts, water-25 parts, solvent-50 parts).

Figure 1. General view of the solvent chamber installed at the Leningrad Isolation House.

insecticidal power, for mass processing of lousy things in chambers installed at bathhouses and sanitary stations, and to develop a type of chamber (Fig. 1). Both solvent-naphtha and other solvents should be used for sanitary purposes in a purified state.

Figure 2. Assembly diagram of the heating devices of the Okunevsky disinfection chamber. The chamber is installed at the Gavan sanitary station (Leningrad). Chamber capacity 10 m³. "Purified solvents". Solvent chambers have the appearance of a small room with two doors, with a capacity of 4-6-12 m³; they are heated by steam, by a system of coils located on the bottom and along the sides of the chamber (Fig. 2). The heating surface

Figure 3. Okunevsky solvent chamber at a dormitory bathhouse (Leningrad). Frontal section. The chamber is equipped with supply-and-exhaust ventilation and devices for recirculating heated air and solvent vapors (designed by Prof. L. A. Pogorshelsky).

of the coils is equal to 2.4-3 m² per 1 m³ of the chamber. The temperature of the steam in the steam generator for heating the coils is 142.8°; pressure 3 atm. Solvent chambers can be installed at any enterprise that has a satisfactory steam system. The chamber operates at a temperature of 60-65° with an admixture of solvent vapors. The solvent is supplied by a nozzle, as in the Japanese chamber, which is best, or evaporated from pans placed on the coils. Solvents are introduced at 150 cm³ per 1 m³. For every cubic meter of the chamber, 2.5-3 sets of clothing are loaded in winter and 3-4 sets in summer; the entire session lasts 1 hour 10 minutes. The chamber does not damage either fur or leather dry items. Under the nozzle there must be

Figure 4. Longitudinal section of the Okunevsky chamber.

an umbrella installed, as in the Japanese chamber. The chamber can also serve, in the presence of a nozzle, for steam-formalin disinfection (according to the Japanese method). In the latter case, it can serve

Figure 5. Plan of the Okunevsky chamber.

for the purposes of disinfection and disinsection. The solvent chamber must be equipped with supply-and-exhaust ventilation and may have devices for recirculating heated air and solvent vapors (Fig. 3-5). For delousing individual sets of clothing and individual bedding items at room temperature, solvent boxes (Fig. 6) are used, in which the sprayed items are kept for 6-12 hours. Boxes for clothing are also arranged according to the type of thermostats—double-walled; hot water (80-90°) is poured between the walls to activate the solvent; items are kept in the warm box for no less than 3 hours. The box holds 2 mattresses, 4 pillows, and 2 blankets.

Figure 7. Okunevsky box for rapid delousing of clothing with solvent vapors or vapors of a mixture of solvent and gasoline (1:3): 1-gasket; 2-terminals; 3-carbon electric lamp for 100-150 candlepower; 4-crate; 5-shelf; 6-hot water; 7-fabric cover.

mixture is used for disinfection and disinsection of residential premises (lysol-10 parts, green soap-25 parts, solvent-65-70 parts). To enhance the insecticidal action, turpentine and kerosene (10-20%) are added. 20% hot soap-cresol solvent solutions are used for treating dwellings. A 25% solvent-soap emulsion (solvent-25 parts, soap-5 parts, water-70 parts) was tested by I. M. Reshetnikov for the treatment of lice in horses. Skin irritation in horses is not observed; the treatment effect is good, the operation is simple. When working with solvents, smoking is strictly prohibited and measures for protecting the health of workers are observed.