Geo. Adlam & Sons Ltd. Bristol, Pump Desiccator for Telescopes and Binoculars, Admiralty Patt. 12128, 1944 (View 1)
George Adlam & Sons was a British company founded in 1800 which by the 20th century specialized in metalwork and the manufacture of equipment for the brewing and chocolate industries. During WW II they manufactured a hand pump desiccator for British Barr & Stroud naval binoculars as well as designing a Royal Navy brewing ship to supply soldiers in the Pacific with beer. The desiccator was actually most likely designed by Barr & Stroud in 1937 who subsequently published a manual for its use (William Reid, “Barr & Stroud ‘Nitrogen-filled Binoculars’: the facts” Bulletin of the Scientific Instrument Society No. 81, 2004, p. 34).
Adlam’s hand pump desiccator was used to fill the Barr & Stroud CF41 7x50, Britain’s primary WW II handheld naval binocular, with dry air to prevent internal condensation and fungus. Although the CF41 which entered service in 1935 was not originally equipped with desiccator connections for dry air purging, at some point during the war they were added to new CF41’s and CF42’s, and older CF41’s, CF42’s as well as some CF30’s were retrofitted with them (Reid, page 35). See: www.flickr.com/photos/binocwpg/4408164546/in/photolist-7H... for more information about the CF41, and www.flickr.com/photos/binocwpg/4407463057/in/set-72157623... for a view of the desiccator tubes inside its prism box. It is a misconception (often originating in eBay sales) that the dry air ports found on CF41 and other WW II binoculars such as the Canadian REL 7x50’s and British Bino Prisms No. 2 and 5 were for nitrogen purging. This is not true. During WW II no countries manufactured nitrogen filled handheld binoculars, and this did not become a common practice until the early 1970’s.
The Adlam Pump Desiccator weighs approximately 25 kilograms and fits in a wooden storage box (see View 2: www.flickr.com/photos/binocwpg/19975967603/in/dateposted/ ). It is operated by connecting a rubber outlet tube (1) and inlet tube (2) to the dry air connections on the prism box of the binocular (3- a CF41). Then, the apparatus is hand pumped to draw the air from inside the binocular through a silica gel filled container (4) within the desiccator (See View 3: www.flickr.com/photos/binocwpg/20603416811/in/photostream/ ) for drying before being pumped back into the binocular. Several pumpings may be required before the air is satisfactorily de-humidified which is measured by a hygrometer (5) attached to the unit (see View 4: www.flickr.com/photos/binocwpg/20587802952/in/photostream/ ). There is also a manometer (6) attached to the desiccator (see View 5: www.flickr.com/photos/binocwpg/20570545056/in/photostream/ ) which may have been used to test the air-tightness of the system including testing the binocular to locate any leakage points, and finally there is a screw-down valve (7) for reducing pressure.
See Views 6 and 7: www.flickr.com/photos/binocwpg/20596725635/in/photostream/ and www.flickr.com/photos/binocwpg/19974122004/in/photostream/ for close-ups of the markings on the base of the desiccator and View 8: www.flickr.com/photos/binocwpg/19975766523/in/photostream/ for “parking” i.e. storage of the rubber tubes when not in use.
Note: If you have a vintage binocular you either wish to sell or would just like some information about, I can be contacted at flagorio12@gmail.com .
Geo. Adlam & Sons Ltd. Bristol, Pump Desiccator for Telescopes and Binoculars, Admiralty Patt. 12128, 1944 (View 1)
George Adlam & Sons was a British company founded in 1800 which by the 20th century specialized in metalwork and the manufacture of equipment for the brewing and chocolate industries. During WW II they manufactured a hand pump desiccator for British Barr & Stroud naval binoculars as well as designing a Royal Navy brewing ship to supply soldiers in the Pacific with beer. The desiccator was actually most likely designed by Barr & Stroud in 1937 who subsequently published a manual for its use (William Reid, “Barr & Stroud ‘Nitrogen-filled Binoculars’: the facts” Bulletin of the Scientific Instrument Society No. 81, 2004, p. 34).
Adlam’s hand pump desiccator was used to fill the Barr & Stroud CF41 7x50, Britain’s primary WW II handheld naval binocular, with dry air to prevent internal condensation and fungus. Although the CF41 which entered service in 1935 was not originally equipped with desiccator connections for dry air purging, at some point during the war they were added to new CF41’s and CF42’s, and older CF41’s, CF42’s as well as some CF30’s were retrofitted with them (Reid, page 35). See: www.flickr.com/photos/binocwpg/4408164546/in/photolist-7H... for more information about the CF41, and www.flickr.com/photos/binocwpg/4407463057/in/set-72157623... for a view of the desiccator tubes inside its prism box. It is a misconception (often originating in eBay sales) that the dry air ports found on CF41 and other WW II binoculars such as the Canadian REL 7x50’s and British Bino Prisms No. 2 and 5 were for nitrogen purging. This is not true. During WW II no countries manufactured nitrogen filled handheld binoculars, and this did not become a common practice until the early 1970’s.
The Adlam Pump Desiccator weighs approximately 25 kilograms and fits in a wooden storage box (see View 2: www.flickr.com/photos/binocwpg/19975967603/in/dateposted/ ). It is operated by connecting a rubber outlet tube (1) and inlet tube (2) to the dry air connections on the prism box of the binocular (3- a CF41). Then, the apparatus is hand pumped to draw the air from inside the binocular through a silica gel filled container (4) within the desiccator (See View 3: www.flickr.com/photos/binocwpg/20603416811/in/photostream/ ) for drying before being pumped back into the binocular. Several pumpings may be required before the air is satisfactorily de-humidified which is measured by a hygrometer (5) attached to the unit (see View 4: www.flickr.com/photos/binocwpg/20587802952/in/photostream/ ). There is also a manometer (6) attached to the desiccator (see View 5: www.flickr.com/photos/binocwpg/20570545056/in/photostream/ ) which may have been used to test the air-tightness of the system including testing the binocular to locate any leakage points, and finally there is a screw-down valve (7) for reducing pressure.
See Views 6 and 7: www.flickr.com/photos/binocwpg/20596725635/in/photostream/ and www.flickr.com/photos/binocwpg/19974122004/in/photostream/ for close-ups of the markings on the base of the desiccator and View 8: www.flickr.com/photos/binocwpg/19975766523/in/photostream/ for “parking” i.e. storage of the rubber tubes when not in use.
Note: If you have a vintage binocular you either wish to sell or would just like some information about, I can be contacted at flagorio12@gmail.com .