Chemical Delay Igniter

Connected to charge by threads in base

The delay time can be varied by the number of celluloid washers, and igniters of various times are differentiated by the colors of the large threaded on the upper part of body, as follows:

The body houses a steel striker retained against a compression of a steel spring by a celluloid washer which projects into a cylindrical chamber at the upper end of the body. A detonator fitted with a flanged cap is secured to the lower end of the body by a was-her and a screw-threaded adapter slotted laterally at the lower extremity to permit the insertion of the flanged detonator head beneath the detonator locating ring.

The exterior of the body's upper portion has a large-pitch square thread onto which screws the cap assembly with acetone sealed in the hollow-end cap by screwing the adapter collar hard down on the alumium ring.

The ring presses the circumference of the lead closing disc into a groove in the wall of the end-cap, as shown. For transport, the end-cap is screwed down and the long leg of the wire safety pin passed through a hole in the upper end of the body, while the short leg is passed through a hole in the collar.

The safety pin is withdrawn and the end-cap assembly screwed down. A lead closing disc, cut by the chamfered edge of the upper end of the igniter body and projection from the end-cap, permits acetone to enter the chamber and surround the celluloid washer.

Unless the arming operation is carried out with the end-cap down, the acetone leaks out the air-ecape hole. When the end-cap is screwed down, the adapter collar bears hard against the fiber washer to form an effective seal. When the acetone dissolves the cel-luloid washer, the striker is released to initiate detona-tion.

Figure 245
Chemical Delay Igniter