This post refers to a piece of Horne product literature entitled 'Horne's Specialities' that we believe dates from the 1930s.
In the 1930s the regulations regarding trade descriptions and inherent or suggestive claims about a product's performance or function embedded in the product’s name would have been rather less demanding than they are now. Was the silent heater silent? Almost certainly not, but what it offered was a vastly reduced degree of noise and vibration to any user of steam that wished to heat water by directly injecting it with steam.
As steam bubbles condense in water they collapse and this causes noise and vibration. The vibration can cause significant wear to welded joints and other fittings such as would be found on hot water storage tanks. The silent heater caused the steam supply to be split into many tiny streams and the collapse of very tiny bubbles of steam resulted in greatly reduced levels of noise and vibration.
The grenade-like device shown on page twenty is no longer made and the description doesn’t choose to include the fact that the design worked by filling the body of the fitting with lead shot!
Today we manufacture the steam injection heater, which offers the same benefits but by means of a completely different design and without the inclusion of lead shot; the steam injection heater is manufactured entirely from stainless steel.