ZA200604520B

ZA200604520B - Control valve assembly

Info

Publication number: ZA200604520B
Application number: ZA200604520A
Authority: ZA
Inventors: Buehrmann Rudolph
Original assignee: Buehrmann Trust
Priority date: 2005-03-14
Filing date: 2006-06-02
Publication date: 2007-02-28

Description

, ’ . NU © =

CONTROL VALVE ASSEMBLY

FIELD OF THE INVENTION

The invention relates to a control valve assembly which provides for a take-off flow as required by a specific appliance, and particularly where the take-off flow is to a cooling coil in underground mining operations.

BACKGROUND TO THE INVENTION

A minimum flow of water is required for the operation of certain appliances. One such appliance is an air cooling coil in underground mining operations.

The flow of pressurized water in pipes to the working areas in mines is dependent on the operation of hydraulic equipment in those areas. The fluctuations in flow usually require that the water must be continually passed through a cooling coil and dumped. This normally goes to a drain and must then be recycled.

OBJECT OF THE INVENTION

It is an object of this invention to provide a control valve assembly that minimizes the volume of take-off water that is dumped.

i : 3

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a control valve assembly comprising a housing with an inlet and an outlet, a main poppet spring biased towards the inlet against a main valve seat in the housing, a take-off conduit connectable on the inlet side to provide flow through an appliance and back via a return conduit having a non-return valve to the outlet side of the assembly, a vent conduit extending from the return conduit, between the appliance and non- return valve, through an auxiliary valve to a vent, with a connector from the main poppet whereby the auxiliary-valve is opened as the main valve is closed.

The invention further provides for the auxiliary valve to include an auxiliary poppet spring biased against an auxiliary valve seat.

Further features of the invention provide for the auxiliary valve to have an auxiliary valve chamber supported in the housing to the inlet side of the main valve seat with the vent conduit extending through the housing to provide a rigid support for the auxiliary valve chamber; for the main poppet to be mounted on a spindle extending through the main valve seat and axially slidable in a perforated support to the outlet side with the inlet end of the spindle guided to act against the auxiliary poppet; and for the spindle adjacent the inlet end to extend slidably into the auxiliary valve chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will be described, by way of example only, with reference to the drawing:

Figure 1 which shows a schematic cross-sectional view of a control valve assembly in accordance with this invention.

: | 4

Lo 2:22000.0v02020

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1, a control valve assembly (1) is securable into a pressurized water supply line (2). The line (2) will supply working areas in an underground mine. The assembly (1) has a housing (3) with an inlet (4) and an outlet (5). A perforated support (6) is located at the outlet (5) side of the assembly (1). A main poppet valve (7) is located centrally in the housing (3).

The valve (7) has a main poppet (8) which is annular and mounted on a spindle (9). The spindle (9) extends longitudinally through the housing (3). The spindle (9) is axially slidable with one end (9.1) extending through the support (6). A spring (10) is provided around an inwardly stepped portion of the spindle (9) and against the support (6). The spring (10) biases the poppet (8) against a main valve seat (11) which is also annular.

The other, inlet end (9.2) of the spindle (9) extends into an auxiliary valve chamber (12). This end (9.2) of the spindle (9) is slidably received in a seal (13).

The chamber (12) is supported by a pair of rigid pipes (14) and (15), both of which extend through the wall of the housing (3). In the chamber (12), is an auxiliary poppet (16) and corresponding valve seat (12). Both are annular.

These components form an auxiliary valve (18). This valve (18) controls flow from an inlet side fed by pipe (14) to an outlet side into pipe (15). The chamber (12) provides a cylinder (19) which slidably receives the rear end of the poppet (16). The poppet (16) has an enlarged head providing a shoulder (20). A spring (21) acts against the shoulder (20) biasing the poppet (16) against its seat (17).

The forward end of the poppet (16) has an extension (22) of reduced diameter.

A passage (23) through the poppet (16) communicates between its downstream side and the cylinder (19) behind the poppet (16).

A take-off conduit (24) connects the inlet side of the assembly (1) to a cooling coil (25). A separate valve (26) may be provided in conduit (24). A return conduit (27) with a non-return valve (28) connects the cooling coil (25) back to the outlet (5) side of the assembly (1). The cooling coil is an example of an

R ) appliance (25) which requires a constant flow (Qc) therethrough. A vent conduit : (29), which includes pipe (14) and pipe (15), connects the return conduit (27) to a vent (30). The vent (30) will conveniently lead to a tank (31).

Also shown is a pressure gauge (32) connected across the main poppet valve (7). In use, the main valve (7) maintains a constant pressure drop (AP) across the poppet (8) and seat (11). This is done by means of the main spring (10). AP is the difference between the pressure at the inlet (P4) and pressure at the outlet (P,). In the result the constant flow (Qc) through cooling coil (25) is provided. This is under circumstances where there is sufficient flow (Q2) to working areas downstream from the assembly (1). Figure 1 shows the assembly (1) in this condition with flow to the assembly (1) indicated by (Q1).

When the downstream flow demand (Q2) drops to a minimum flow (Qc) required by the cooling coil (25), the main poppet (2) moves towards its closed position and pushes auxiliary poppet (16) off its seat (17). The shortfall (Qd) below the required flow (Qc) is thus dumped by the open auxiliary valve (18) under these flow conditions.

In summary, under high flow demand conditions (where Q2 is greater than Qc),

Q1 will be equal to Q2. Flow through the main poppet valve (7) will be equal to

Q1 less Qc, which is channeled through the coil (25). Under low flow demand conditions (where Qz is smaller than Qc), the auxiliary valve (18) is opened as the main valve (7) closes. Flow (Qd) through this valve (18) will be equal to Qc less Qz2, and Q2 will be equal to Q1 less Qa.

The valve assembly (1) provides a constant required flow to a cooling coil (25), or other appliance, and reduces the volume of water dumped. More particularly, when flow demand to working areas is suitably high, no water is dumped as a result of cooling coil operation.

A person suitably skilled in the art will appreciate that variations may be made to the features of the described embodiment without departing from the scope of the current invention. For example, the connector between the main poppet (8) and auxiliary valve (18), may be other than the spindle (9) described.

Claims

~ —_ - . CLAIMS SE

1. A control valve assembly comprising a housing with an inlet and an outlet, a main poppet spring biased towards the inlet against a main valve seat in the housing, a take-off conduit connectable on the inlet side to provide flow through an appliance and back via a return conduit having a non-return valve to the outlet side of the assembly, a vent conduit extending from the return conduit, between the appliance and non-return valve, through an auxiliary valve to a vent with a connector from the main poppet whereby the auxiliary valve is opened as the main valve is closed.

2. A valve assembly as claimed in claim 1 in which the auxiliary valve includes a poppet spring biased against an auxiliary valve seat.

3. A valve assembly as claimed in claim 2 in which the auxiliary valve has an auxiliary valve chamber supported in the housing to the inlet side of the main valve seat with the vent extending through the housing to provide a rigid support for the auxiliary valve chamber.

4. A valve assembly as claimed in claim 3 in which the main poppet is mounted on a spindle extending through the main valve seat and axially slidable in a perforated support to the outlet side with the inlet end of the spindle guided to act against the auxiliary valve poppet.

5. A valve assembly as claimed in claim 4 in which the spindle adjacent the inlet end extends slidably into the auxiliary valve chamber.

6. A control valve assembly substantially as herein described with reference to the accompanying drawing.

DATED THIS 2'° DAY OF JUNE 2006 BOWMAN JOHN & KERNICK FOR THE APPLICANT