WO2003071372A1

WO2003071372A1 - Control valve

Info

Publication number: WO2003071372A1
Application number: PCT/ZA2003/000030
Authority: WO
Inventors: John Edward Lewthwaite
Original assignee: John Edward Lewthwaite
Priority date: 2002-02-25
Filing date: 2003-02-24
Publication date: 2003-08-28
Also published as: AU2003215048A1

Abstract

The invention provides a control valve comprising a body member having a first flow passage therethrough for a primary fluid; a valve seat in the first flow passage; and a valve closure movable towards the valve seat to close the valve, and away from the valve seat to open the valve; a sensor for determining characteristics of a secondary fluid, the sensor being in communication with the valve closure, to cause movement thereof towards or away from the valve seat in accordance with the characteristics of the secondary fluid, and separation means separating the primary fluid and the sensor within the body of the valve.

Description

CONTROL VALVE

Field of the Invention

THIS invention relates to a control valve.

Background to the Invention

The pre-heating of diesel fuel before it is used for combustion in a diesel engine is

well known. Diesel fuel is passed through a heat transfer mechanism, where heat is

transferred from another fluid, such as water from the engine cooling system, to the diesel fuel. For optimum combustion efficiency, the diesel fuel is required to be

maintained at a certain temperature. The temperature of the diesel is controlled by

increasing or decreasing the flow rate of the hotter fluid through the heat transfer

mechanism.

Object of the Invention

It is an object of the present invention is to provide a novel control valve for

regulating the flow of a primary fluid in accordance with characteristics of a

secondary fluid. A further object of the invention is to provide means for regulating the temperature

of a fuel supply.

Summary of the Invention

According to the invention, a control valve comprises a body member having a first

flow passage therethrough for a primary fluid; a valve seat in the first flow passage;

and a valve closure movable towards the valve seat to close the valve, and away

from the valve seat to open the valve; a sensor for determining characteristics of a

secondary fluid, the sensor being in communication with the valve closure, to cause

movement thereof towards or away from the valve seat in accordance with the

characteristics of the secondary fluid, and separation means separating the primary

fluids and the sensor within the body of the valve.

Further according to the invention, the valve closure is adapted to be moved

progressively towards or away from the valve seat, to open or close the valve

respectively. „,-,-„„ _

PCT/ZA03/00030

Further according to the invention, the valve includes a second flow passage for the

secondary fluid with the sensor being in operative communication with such second

flow passage.

Also according to the invention a diaphragm acts to separate the primary fluid and

the sensor.

Also according to the invention the valve closure is biased away from the valve seat

by a biasing means and the sensor acts on the valve closure against the action of the

biasing means to close the valve.

In a preferred arrangement in accordance with the invention the sensor preferably

acts on the valve closure indirectly, through the agency of resilient means,

preferably a compression spring.

In one application according to the invention a sensor is adapted to sense the

temperature of the secondary fluid, and the sensor includes an actuator shaft that is

adapted to extend or retract in accordance with the sensed temperature. With such an arrangement therefore the actuator shaft acts upon the valve closure (directly or

indirectly) to move the latter.

Also included within the scope of the invention is a method of controlling the flow

of a primary fluid in accordance with characteristics of a secondary fluid,

comprising the steps of providing a control valve substantially as described above,

causing the primary fluid to flow through the first flow passage in the valve,

contacting the sensor with a secondary fluid, whereby characteristics of the

secondary fluid are determined by the sensor, and causing the sensor to act directly

or indirectly on the valve closure progressively to open or close the valve, whereby

flow of the primary fluid is controlled.

Further according to this aspect of the invention, the method includes the step of

causing the valve closure to move progressively towards or away from the valve

seat, to close or open the valve, by means of the sensor.

The method of the invention will in particular find application in diesel internal

combustion engines wherein the secondary fluid is a diesel fuel, and the primary fluid is coolant from the engine's cooling system. With such an arrangement, the

diesel fuel can be heated or cooled as required in a heat exchanger, by means of

flow of the primary fluid through such heat exchanger, the flow thereof being

controlled by the valve of the invention. The invention is not restricted to the

above applications, and will doubtless find other useful applications in industry.

Brief Description of the Drawings

In order more clearly to illustrate the invention an embodiment thereof is described

hereunder purely as an example without limiting the scope of the invention, with

reference to the accompanying drawing which is a schematic sectioned elevation of

a control valve in accordance with the invention.

Detailed Description of Drawings

Referring to the drawing, a control valve (100) comprises a body member (1), a

first flow passage (Seen in Figure 1 as arrow A) through the body member (1) for a

secondary fluid, and a valve (5) in the flow passage (A), the valve (5) comprising a valve seat (23) and a valve closure member (12) movable towards or away from the

valve progressively to close or open the valve (5).

The valve (5) further includes a sensor (7) that is adapted to sense the

characteristics of a secondary fluid, such as the temperature thereof. The sensor

(7) includes an actuator rod (9) that extends or retracts in accordance with the

relevant characteristic of the secondary fluid. The actuator rod (9) is thus utilised

to urge the valve closure member (12) towards or away from the valve seat (23) in

accordance with the sensed characteristics of the secondary fluid. In the

arrangement illustrated, the sensor (7) is disposed in a second flow passage (Seen in

Figure 1 as arrow B) in the control valve (100) through which the secondary fluid

flows in use. In an alternative arrangement, not shown, the sensor (7) could for

example be exposed to atmosphere or to inserted into a pipe in which the secondary

fluid is flowing.

It is a feature of the invention that the first flow passage (A) and the second flow

passage (B) will be separated within the control valve (100) by means of a flexible

diaphragm (21) to prevent contamination of the primary and secondary fluid. In the arrangement illustrated, the diaphragm (21) is disposed between the valve closure

(12) and the actuator rod (9) of the sensor (7) as illustrated. The diaphragm (21)

also prevents foreign matter , such as scale in the engine coolant water, from

damaging or congesting critical sliding components in the mechanism of the control

valve (100).

The valve shown comprises a body member (1) that has an inlet port (14), a valve

seat area (23) and an outlet port (15). The one end of the body member (1) is

enclosed by an end plug (3). The other end of the body member (1) is terminated

by a diaphragm (21) which is held in place by a bonnet (2). The sensor (7) is a

thermostat. A sensor housing (4) is attached to the bonnet (2) by a compound thread

nut (31), thus also securing the sensor (7) to the bonnet (2).

The bonnet (2) encloses a diaphragm piston (10). The diaphragm (21) is secured to

the diaphragm piston (10) by means of a threaded diaphragm securing member

(11). The valve closure member (12) is able to slide freely within the diaphragm-

securing member (11), also causing a control rod (25) to move with it. The valve closure member (12) is biased towards the valve seat face (23) by a

compression spring (20) and is restrained by a shoulder (18) on the control rod

(25). The control rod (25) is affixed to a main spring plunger (17). The main

spring plunger is positively biased onto a stopper face (26) by a main spring (19).

Externally and internally, sealing is effected by O-rings (27, 28, 29 and 30).

In use the control valve (100) is a normally open device thus the primary fluid is

able to flow freely through the valve. The flow path can be seen in Figure 1 as

arrow A. Primary fluid flows into the valve through inlet port (14) and into a semi-

annulus cavity (13). It then passes into valve cavity (24), over the valve seat (23)

and into a valve aperture (16). The primary fluid leaves the control valve (100) at

an outlet port (15), which is connected to a heat transfer device (not shown). The

secondary fluid enters the sensor housing (4) through an inlet aperture (8) and exits

the housing at an outlet aperture (6). The sensor (7), in this case a thermostat,

reacts to the temperature by the extension or retraction of the actuator rod (9) . The

actuator rod (9) contacts the diaphragm piston (10) at a face (31) causing the

diaphragm piston assembly (10, 11, and 12) to move against the action of the

biasing main spring (19). The valve is closed when the valve closure member (12) „,-,-„„ _

PCT/ZA03/00030

contacts valve seat (23). Efficient sealing is effected through the use of the sealing

O-ring (22). The valve closure member (12) is held in contact with the valve face

(23) by a secondary compression spring (20). Residual heat effect in the sensor (7)

may cause the actuator rod (9) to continue moving in the direction of the valve seat

(23). This residual heat effect is accounted for by the compression of secondary

compression spring (20), preventing internal damage to the sensor (7). When the

actuator rod (9) retracts as the temperature of the secondary fluid cools, the biasing

main spring (19) biases the diaphragm piston assembly (10, 11, and 12) towards

open.

Doubtless variations of the invention in detail are possible without departing from

the principles set out in the consistory clauses.

Claims

1. A control valve comprising a body member having a first flow passage

therethrough for a primary fluid; a valve seat in the first flow passage; and

a valve closure movable towards the valve seat to close the valve, and away

from the valve seat to open the valve; a sensor for determining

characteristics of a secondary fluid, the sensor being in communication with

the valve closure, to cause movement thereof towards or away from the

valve seat in accordance with the characteristics of the secondary fluid, and

separation means separating the primary fluid and the sensor within the

body of the valve.

2. The control valve according to claim 1 wherein the sensor is adapted to

move the valve closure progressively towards or away from the valve seat

progressively to open or close the valve respectively.

3. The valve according to claim 1 or claim 2 wherein the separation means

comprises a diaphragm which separates the primary fluid and the sensor.

4. The valve according to any one of claims 1 to 3 wherein the valve closure is

biased away from the valve seat by a biasing means and the sensor acts on

the valve closure against the action of the biasing means to close the valve.

5. The valve according to claim 4 wherein the sensor acts on the valve closure

indirectly, through the agency of resilient means.

6. The valve according to claim 5 wherein the sensor acts on the valve closure

indirectly through the agency of a compression spring.

7. The valve according to any one of claims 1 to 6 wherein the sensor is

adapted to sense the temperature of the secondary fluid, and the sensor

includes an actuator shaft that is adapted to extend or retract in accordance

with the sensed temperature.

8. The valve according to claim 7 wherein the actuator shaft acts upon the

valve closure indirectly to move the latter towards or away from the valve

seat.

9. The valve according to any one of claims 1 to 8 wherein the body member

includes a second flow passage for the secondary fluid, and the sensor is in

fluid communication with such secondary fluid.

10. The valve according to claim 9 wherein the sensor is a thermostat which

projects into the second flow passage.

11. A control valve comprising a body member having a first flow passage

therethrough for a primary fluid; a valve seat in the first flow passage; and

a valve closure movable towards the valve seat to close the valve, and away

from the valve seat to open the valve; a sensor for determining

characteristics of a secondary fluid, the sensor being in communication with

the valve closure, to cause movement thereof towards or away from the valve seat in accordance with the characteristics of the secondary fluid, the

sensor acting on the valve closure indirectly through the agency of resilient

means.

12. The valve according to claim 11 wherein the resilient means comprises a

compression spring.

13. The control valve comprising a body member having a first flow passage

therethrough for a primary fluid; a valve seat in the first flow passage; and

a valve closure movable towards the valve seat to close the valve, and away

from the valve seat to open the valve; a sensor for determining

characteristics of a secondary fluid, the sensor being in communication with

the valve closure, to cause movement thereof towards or away from the

valve seat in accordance with the characteristics of the secondary fluid,

wherein the sensor acts on a bonnet structure which is separated from the

first flow passage by means of a flexible separation means.

14. The valve according to claim 13 wherein the bonnet structure acts on the

valve closure indirectly through the agency of resilient means.

15. The valve according to claim 14 wherein the resilient means comprises a

compression spring.

16. The valve according to any one of claims 13 to 15 wherein the sensor is a

thermostat which is located in a housing, and a secondary flow passage for

the secondary fluid passes through such housing so that a portion of the

sensor is contracted by the secondary fluid.

17. A method of controlling the flow of a primary fluid in accordance with the

characteristics of a secondary fluid comprising the steps of providing a

control valve as claimed in any one of claims 1 to 16, causing the primary

fluid to flow through the first flow passage in the valve, contacting the

sensor with a secondary fluid, whereby characteristics of the secondary

fluid are determined by the sensor, and causing the sensor to act directly or indirectly on the valve closure to open or close the valve, whereby flow of

the primary fluid is controlled.

18. A method according to claim 17 including the step of causing the valve

closure to move progressively towards or away from the valve seat

progressively to close or open the valve, by means of the sensor.

19. The method according to claim 17 or claim 18 wherein the secondary fluid

is a diesel fuel and the primary fluid is a coolant for an internal combustion

engine cooling system.

20. A control valve substantially as herein described and exemplified with

reference to the accompanying drawings.

21. A method of controlling the flow of a primary fluid in accordance with the

characteristics of a secondary fluid substantially as herein described and

exemplified with reference to the accompanying drawings.