This document describes a closure member for cistern overflow pipes that prevents air currents from entering the cistern. It consists of a housing with a vertically disposed inlet tube containing a buoyant cork ball closure member. When the liquid level in the cistern rises, the cork ball is displaced upwards, allowing overflow to pass through the outlet. When the level falls, the cork ball returns to its seating under gravity, blocking air flow into the cistern.

1. * GB780196 (A)
Description: GB780196 (A) ? 1957-07-31
Closure member for cistern and like overflow pipes
Description of GB780196 (A)
PATENT SPECIFICATION
i ate of filn)g Comnplete Specification: July 13, 1955.
_Aijlication, Date: June 4, 1954. Noo. 16552 /514.
Complete Specification Published: July 31, 1957.
Index at Acceptance:-Class 1 5, VP8.
International Classification:-FO6k.
COMPLETE SPECIFICATION.
Closure Member for Cistern and like Overflow Pipes.
We, FREDERICK HENRY SHERBOURNE, Of Winterhey House, Winterhey Lane,
Horwich, in the County of Lancaster, and JAMES HILL, of Castlefield
House, Manchester Road,
Blackrod, in the County of Lancaster, both British Subjects, do hereby
declare the invention, for which we pray that a patent may be granted
to us, and the method by which it is to be performed, to be
particularly described in and by the following statement -
This invention relates to the overflow pipes of cisterns, tanks and
like water or liquid storage vessels and particularly but not
exclusively, to cisterns of the type in which the water or liquid
level is maintained by means of a valve operated by a floating ball.
It has been found that, in certain instances, freezing of the supply
pipe to the vessel and/or of water in the vessel occurs as a result of
a current of cold air passing into the cistern from the overflow pipe
provided therein. Thus a storage tank or cistern (or the supply
thereto) disposed in a warm part of a building may freeze up in cold
weather in spite of the apparent inability of the elements to have any
effect thereon. The object of the present invention, therefore, is to
provide a fitting for use on the overflow pipe of a water cistern or
like storage vessel which will prevent air currents passing into the
cistern, so that the freezing up in cold weather conditions previously
referred to is avoided.

2. According to the present invention a nonreturn valve for attachment to
a cistern or like liquid storage vessel and an overflow pipe therefor
comprises a housing having an 4,6 inlet in the form of a vertically
disposed hollow tube having a seating at its lower end for a buoyant
closure member and an outlet adjacent its upper end, which latter [E F
is closed, said outlet being in the form of a branch tube located at
right angles to the inlet, whereby the buoyant closure is displaced
from its seating by a rise in level of the liquid to allow overflow
thereof from the storage vessel and returns to its seating under the
influence of gravity when the liquid level falls.
The non-return valve conveniently comprises an outlet of such a
diameter so as to allow free movement of the closure member in the
vertical direction and relatively no movement in the lateral direction
and the seating for the closure member is of reduced diameter.
The invention will be described further, by way of example, with
reference to the accompanying drawings in which:Fig. 1 is a
perspective view of a union constructed in accordance with the present
invention; and Fig. 2 is a cross-sectional elevation showing the union
in position in a cistern.
The union for securing an overflow pipe into a circular hole
appropriately disposed in a side wall 11 of a water cistern comprises
the usual sleeve or bush 12 which is flanged at 13 and externally
threaded at 14 and which is also adapted to be secured to one end of
the overflow pipe 10 for example, by means of a second internal screw
thread (not shown). This sleeve is secured into the hole in the
cistern wall by locating the externally threaded portion 14 therein
and screwing a union nut 15 thereon so that the wall 11 of the cistern
is gripped between the flange 13 and the union nut 15.
The non-return valve according to the present invention is formed
integrally with the aforesaid union nut 15, and is in the form of a
vertically disposed hollow tube 16 which is closed at its upper end
17. The nut 15 and the tube 16 could quite conveniently be cast or hot
pressed in a single 7801,96 unit, although obviously it is possible
for the valve to be made as a separate entity capable of being secured
to the union nut 15.
The axis of the union nut 15 will naturally be horizontal or near
horizontal, so that, as the hollow tube 16 is vertical. the nut will
be secured to part of the curved surface of the tube, the general
plane of the nut 15 being approximately parallel with the axis of the
tube 16, and the nut 15 will, of course, be in communication with the
tube 16.
The lower end of the tube 16 is reduced in diameter, by pressing
therein a circular disc or ring or by flanging over as at 18, and
within the tube 16 is located a cork ball 19 capable of locating into

3. the reduced diameter portion so as to close the end of the tube 16.
The reduced diameter portion therefore forms a seating at the lower
end of the tube 16 while the cork ball 19 forms a closure member
thereof. To ensure that the ball 19 cannot pass from the tube 16 into
the union nut 15, a pin or cotter 20 is secured across the part where
these two latter join one another, so that the space left at each side
thereof is insufficient to allow the ball 19 to pass. Thus the ball 19
is effectively trapped in the tube 16 and is capable only of vertical
and very slight lateral movement therein.
In use, the overflow pipe 10 is secured to the cistern 11 using the
threaded sleeve 14 and the union nut 15 as previously described, the
union nut 15 being disposed within the cistern. Thus the overflow pipe
terminates at the cistern end at the vertical tube 16. The cork ball
19 is held under the influence of gravity in its position on its
seating so preventing passage of any substance or fluid from the
overflow pipe into the cistern 11.
The presence of the invention at the end of the overflow pipe 10 does
not prevent or interfere with the usual or normal operation of the
overflow pipe 10 since, if the level of water in the cistern 11 rises,
the cork ball 19 is carried upwards thereby so allowing water to flow
into the overflow pipe 10 from the cistern 11.
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