An Improved Combined Feed and Stop-valve for Steam Generators.
Year: 1899

page_text: Date of Application, 8th June, 1899-Accepted, 29th July, 1899
COMPLETE SPECIFICATION.
An Improved Combined Feed and Stop-valve for Steam Generators.
I, HERMANN SCHMIDT, of 62, Herderstrasse, Hamburg, in the Empire of
Germany, Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
As is well known in the feed water supply for steam boilers there is always a
non return valve (feed valve), and between this valve and the boiler there is
arranged a stop or cut-off valve which can be closed for the purpose of enabling
the non return valve to be inspected when required to remedy any irregularity
in the working.
In connection with this arrangement there is however the objectionable feature
that at the moment when the forcing action of the feed pump is reversed into
suction the column of water between the boiler and non-return valve is thrown
against the valve owing to the action of the higher pressure in the boiler. These
blows given by the water occur continuously during the working of the feed
pump and they are the stronger the higher the steam pressure in the boiler and
they not only cause a speedy deterioration of the valve and its seat but they are
also responsible for the imperfect working of the valve, the disadvantageous effect
increasing directly with higher boiler pressure and with the quantity of water
thrown back during the change of the stroke of the pump plunger.
According to this invention the afore mentioned disadvantages are obviated
in the improved combination valve by reducing the space between the stop-valve
and the non-return valve to a minimum owing to the latter valve being arranged
in the casing of the stop valve. Furthermore the blow from the reduced quantity
of water, is avoided by causing the return current to flow in a direction exactly
central but opposite that of the closing of the valve. In this manner the working
of the valve is noiseless and greater durability is ensured.
My improved combination feed and stop-valve is illustrated in the accompany-
ing drawing in which:-
Figure 1 is a cross section and
Figure 2 is a longitudinal section of the valve.
In carrying my invention into effect the part a is connected with the feed pipe
and the end with the steam boiler. The valve e of the stop valve is adapted to
be pressed upon its seat by means of the spindle d and handwheel e, or to be
lifted off its seat by the same to open the valve. The non return valve, f is
guided from below and above as shown and is formed with a double contact sur-
face so as to reduce its stroke; this having been found to be of particular advan-
tage with regard to the motion of the returning water relatively to the down
stroke of the non return valve as has already before been mentioned.
The water from the feed pipe enters the valve casing at a and flows through
the side passages 9 g¹ Figure 1 into the annular space and after lifting the valve f,
passes into the spaces i and j Figure 1 and thence through the open stop valve c
and space b into the boiler. The volume of water between the boiler and non

page_text: return valve thrown back at the commencement of the suction stroke cannot
strike against the valve but its line-force is directed onto the cover while the
waves which travel upwards in opposition to the downward motion of the valve f
allow this latter to close gradually and without noise.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
A combined feed and stop valve characterized by the arrangement of the feed
and the stop valve in a single casing for the purpose of reducing the volume of
water between the boiler and feed valve at the commencement of the suction
stroke, the arrangement being such that the returning water flows in the opposite
direction to the downwardly moving feed valve, substantially as and for the
purpose described.
Dated this 8th day of May 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.