As found with blue-grey vitreous enamelled top, red plastic knob, plain pressure release and flat-topped pressure gauge. There is nothing regarding patents stamped on the globe rest of this one...
I dont have any vapalux lamps dave but you know i am tempted to get myself one of these one day nice lamp is the top always enameled or do they do a brass topped one excuse my ignorance!! pete
As it happens, I've got more brass-topped ones than enamelled, Pete. I just didn't manage to get round to taking photos of them today - I've been a bit busy with installing my new kitchen (6 years and counting! ) - damned lamp-collecting gets in the way!
Pete, I have four E41s with brass heat deflectors. All carry the AM marking for The Air Ministry along with long stores reference numbers on the deflector top. These numbers end with the year mark 40 or 41. Amongst the enamel topped E41s, three have the government crow's foot and dates 1941 and 1942 marked on the lip of the hood. It seems quite strong evidence that the Air Ministry had brass tops the Army had enamel!!
Going back to the lamp, the red control cock knob is made of catalin, an expensive, refined form of bakelite. This was used on the very first lamps made but was soon replaced by a brass knob with an arrow as an economy measure. This in turn was quickly superceded by the familiar maroon bakelite knob which remained a feature of W&B lamps for many years. The manometer on this lamp carries the Willis and Bates Ltd name. This is also an indication of one of the earliest lamps because in July 1941 Willis and Bates Ltd set up another company, Vapalux Ltd., to produce and distribute the lamps. This was less than a year after production had first started. Manometers after this date have no logo!!
