FILED OF INVENTION
The invention relates to a high pressure reverse flow prevention and isolation
device. More particularly the invention relates to reverse flow prevention device
often Called Check Valve or non return valve which are used for high pressure
rating upto and including pressure rating class 4500. These devices are mostly
used in the drain and vent line of super critical boilers where the pressure and
temperature are higher than the normal boiler line ratings. The developed flow
isolation device can be deployed wherever high pressure isolation o
water/steam/oil is required and where reverse flow is to be avoided.
BACKGROUND OF THE INVENTION
Flow isolation devices often called Valves are used for high pressure isolation,
drain or vent service. These devices generally have a shell encompassing the
fluid boundary and Trim portion which helps in isolation of the medium. One of
the applications of such devices is in area where very high pressure is to be
isolated and reverse flow is to be prevented. These devices normally termed as
high pressure check valves are used for drain & vent application in Boilers.
The existing Valves in High Pressure are available in without spring which restrict
installation in horizontal direction only in pipelines.
The purpose of the high pressure drain / vent valve in a Boiler or a pressure
equipment is to effective isolate the upstream from downstream and prevent
reverse flow from downstream to upstream. Another embodiment of this
equipment with a tapered plug. These devices are used in high quantities in
power/utility boilers. Some of these valves are used in the warming-up operation
of the line. These devices are also used as pressure-relieving Valves in large size
high pressure Valves to equalize Bonnet pressure.

Valves are subjected to Pressure and temperature as designated by class rating
of the valve as per the standard ASME B16.34. The class 4500 special is the
maximum rating available in the subject standard.
OBJECT OF THE INVENTION
It is therefore an object of the invention to propose a high pressure reverse flow
prevention and isolation device which can be deployed for high pressure isolation
of water/steam/oil and where reverse flow is to be avoided.
Another object of the invention is to propose a high pressure reverse flow
prevention and isolation device having durable metallic seating and which is
capable of serving at high temperature.
A further object of the invention is to propose a high pressure reverse flow
prevention and isolation device which is provided with a welded Construction
between body and body-extension and thus eliminates the less reliant bolted and
threaded joint prone to leakage.
A still further object of the invention is to propose a simple and sturdy
valve/device with just four components for use in high pressure reverse flow
prevention enabling easier dismantling and servicing.
A still another object is to propose a high pressure reverse flow prevention and
isolation device which provides a spring encompassed in a disk to effect closing
the valve ensuring leak tightness and enable installation in various orientations.

SUMMARY OF THE INVENTION
Accordingly, there is provided a High Pressure reverse flow prevention Device
with spring closure to isolate the inlet and outlet of high pressure fluid flowing
line comprising; a body or shell which encompasses the fluid; the body having
both the inlet and outlet aligned to the piping, a cover or an extension which is
screwed and seal welded onto the body with full penetration welding; the
Seating on Body being integral with hardfacing of suitable material to withstand
the higher pressure & temperature; Seating on Disk hardfacing of suitable
material to effect seating and also withstand the higher pressure & temperature,
the Disk with a small hole of suitable size to act as cushion for the medium
during sudden opening, the spring within the Disk made of suitable material to
withstand corrosion and with suitable spring property to effect positive closure
and to open at sufficient pressure as necessary.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig. -1 cross-sectional view of a High Pressure Reverse Flow Prevention and
Isolation Device according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Figure - 1 illustrates a high pressure reverse flow prevention and isolation device
of the invention. The device comprising a body(Ol) or shell encompassing the
fluid, said body having both the inlet and outlet aligned to the piping and the
inlet and outlet are drilled in the body at a specific angle to the piping when both
are parallel to each other. An extension piece(02) is welded onto the body at
right angle by full penetration weld(03) instead of some oblique angle. A

seat(04) is made integral on body by means of hardfacing of suitable material. A
disk(05) is provided which has one of an integral flat seat(06) for a easier
manufacturing, lapping and re-conditioning and matching with body seat and
hardfaced with suitable material. The body seat (04) and disk seat (05) material
is Stellite. The disk(05) can move through a prefixed distance effecting full open
condition for the fluid flow. The disk(05) has a small hole(07) at bottom
providing cushioning effect by slowly relieving the entrapped medium to outlet
thereby preventing sudden knocking of disk in the event of sudden medium
pressure. The disk(05) encompasses a spring(08) of suitable material
compressed within it and it prevents flow from downstream to upstream. The
spring(08) of suitable material exerts required spring force to close the valve by
engaging the disc seat(06) on body seat(04) and opens when sufficient medium
pressure is exerted below the disk. The spring(08) of suitable material constantly
applies a spring force in ensuring positive closure of the disc(05) and ensuring
leak tightness. The spring material is Inconel. A cover(09) is screwed and seal
welded(lO) onto body(Ol) thereby making disassembly easier by machining of
sealwelding(lO). The disk(05) is closely guided in the cover(09) to ensure non-
chatter, non-vibration during service. The spring within the disc is made of
suitable material to withstand corrosion and with suitable spring property to
effect positive closure and to open at sufficient pressure as necessary. The
positive disk-closure assisted by spring which enables installation in various
orientation as compared to such valves without spring which can be installed in
horizontal orientations only.

We Claim
1) A high pressure reverse flow prevention and isolation device Comprising;
a body(01) or shell for encompassing the fluid;
the said body having inlet and outlet drilled into it;
an extension(02) screwed and seal welded onto the body(01) by full
penetration weld(03);
a seat(04) made integral on the body(01);
a disk(05) having a flat seat(06) matching with body seat; a cover(09)
screwed and seal welded(10) onto body(01) Characterized in that, the
disk(05) is provided with a small hole(07) at bottom for providing
cushioning effect by relieving the entrapped medium to outlet and
encloses a spring(08) within it for exerting required spring force to close
the valve by engaging the disc seat(06) on body seat(04) wherein the
disk(05) prevents flow from downstream to upstream.
2) The device as claimed in claim-1 wherein, the extension(02) is welded
onto the body at right angle.
3) The device as claimed in claim-1 wherein, the body seat(04) and disk
seat(06) are made of hardfacing of Stellite material.
4) The device as claimed in claim-1 wherein, spring force ensures leak
tightness of the disk(05)
5) The device as claimed in claim 1 wherein, the material of the spring is
Inconel.

The invention relates to a high pressure isolation valves for drain/vent/pressure
relief and other similar applications comprising; a body or shell which
encompasses the fluid; the body made out of bar stock and welded to an
extension piece by a full penetration welding; the Body with an inlet drilled at
specific angle to the inlet piping axis; a Seating comprising of welded Stellite
onto the Body; the Seating in the Body Seat made a plane to suit easier lapping
and matching with Disk for isolation; the Cover made of Barstock screwed onto
Body and Sealwelded to ensure leak tightness; a spring made of suitable material
entrapped within the Disk; the Spring of suitable stiffness to provide positive
sealing effect on Disk and also to open on medium pressure under Disk.