The Gas Mask - TM 3-205 War Department Technical Manual

1. Purpose. — This manual is published for the information and guidance of the using arms and services and all personnel charged ■with the issue, alteration, repair, and testing of gas masks in the field. 2. Scope. — This manual explains the designations or numbering systems for the principal components of the gas mask. In order that confusion in storage records and inspections may be avoided, tables giving the main distinguishing characteristics of the various components are furnished. The several special masks or respirators, canisters, and like equipment are also described. Field repair and
• This pamphlet supersedes TK 1120-3S, October 21, 193(1. testing equipment are listed, and directives for these repairs and testing procedures are provided. 3. References. — See appendix I. Section II SERVICE GAS MASK Numbering and identification systems 6 Distinguishing £ h ara cteri sties of various types of gas masks 6 Description and nomenclature of service and diaphragm facepieee parts. 1 Description and nomenclature of canisters and canister parts 8 Description and nomenclature of carrier 9 4. General, — -a. Definition. — The military gas mask is an apparatus designed to purify the air which the soldier breathes. It also protects his eyes and face when he is in an atmosphere contaminated with toxic or irritating gases, vapors, or smokes. b. Co?npo»ents. The complete gas mask consists of three principal ® ]''a« i)ii-ce assembly. © CacnSsteii © Carrier. Ficuhe I. —.Main components of military gas masks. (1) The facepieee (tsxembhj generally consists of the facepieee, containing eyepieces, an outlet valve, a hose connection or angletube. and with a head harness attached. When a connecting hose forms part of the gas mask, it is included in the facepieee assembly. (2) The canister has a hose connection which may or may not include an elbow nozzle, and also one or two inlet valves, depending on the type of canister. These itdet valves are found in all models except the model IX. (3) The car fief is made of a canvas pouch or sack with various straps and buckles for slinging to body of wearer. c. Principle of operation.— (1) The gas mask is an air filter. The path of the air flow in the service gas mask is as shown in figure 2. Air is drawn into the mask when the soldier inhales, and the mask is so constructed that this air must first pass through a canister containing a filtration system. This system comprises both mechanical and chemical fillers, the former filtering out solid and. liquid FigUiuo 2. — Air How system of gifts mask. particles (smoke and dust), and the latter absorbing and neutralizing toxic and irritating gases and vapors. The air after being purified by filtration is drawn to the soldiers face and after being inhaled and exhaled is expelled from the mask through an outlet valve. (2) The facepieee fits snugly to the face so as to be gastight and is held in place by an elastic head harness. It is equipped with eyepieces of safety glass or other transparent material, and a deflector which deflects incoming air against the eyepieces so as to prevent condensation of moisture on the lenses. In addition to this method of reducing dimming of the eyepieces, a soap like substance, known as "antidim," is furnished with each mask — except the training mask — and which, when spread as a than layer over the inner surfaces of the eyepieces, tends further to keep down eyepiece fogging. The facepiece is equipped with an outlet valve through which exhaled air is expelled and a metal tube which is connected to the canister by a corrugated rubber hose.

Republished by Liber Copia LLC for convenient study and reference on any device.