Fluid handling – With indicator – register – recorder – alarm or inspection means – Plural
Reexamination Certificate
2000-06-30
2001-08-28
Rivell, John (Department: 3753)
Fluid handling
With indicator, register, recorder, alarm or inspection means
Plural
C137S554000, C137S625170, C137S636400
Reexamination Certificate
active
06279607
ABSTRACT:
This invention relates to a fluid metering valve, and in particular to a valve of the type in which the fluid flow rate is controlled by adjusting the axial and angular position of a valve element.
In order to provide accurate control over the output flow rate of such a valve, it is important to ensure that the valve element is connected to a drive arrangement used to control the axial and angular positions of the valve element in a backlash free manner such that no movement of the valve element relative to an output of the drive arrangement is permitted. It is an object of the invention to provide a fluid metering valve having such a backlash free connection in a simple and convenient form.
It is also desirable to be able to monitor the position of the valve element. This may be achieved by providing a sensor which monitors the position of a target associated with the drive member. The axial and angular positions of the target are conveniently adjustable.
According to an aspect of the invention there is provided a fluid metering valve comprising a valve element moveable, axially and angularly, by a drive member, a sensor arranged to monitor the position occupied by a target carried by the drive member, and an adjustment arrangement whereby the axial position of the target can be adjusted relative to the drive member independently of the angular position of the target.
Such an arrangement is advantageous in that a datum position for the target can be selected and set relatively easily.
The target is preferably carried by a carrier member which is keyed to an angular adjustment member, the angular adjustment member being in screw-threaded engagement with the drive member. The carrier member is slidable axially relative to the angular adjustment member, and axial adjustment means are conveniently provided to permit adjustment of the axial position of the carrier member relative to the angular adjustment member. In use, the angular position of the target is set by angular movement of the angular adjustment member. Once the correct angular position has been achieved, the axial position of the target is set using the axial adjustment means.
A spring is preferably provided between the drive member and the target such that the mounting of the target to the drive member is substantially backlash free.
The valve is conveniently of the type having two outlet ports, wherein the fluid flow rates to the two outlet ports can be controlled independently of one another by appropriate control of the angular and axial position of the valve element.
According to another aspect of the present invention there is provided a fluid metering valve comprising a valve element which is moveable axially and angularly, a drive member whereby axial and angular movements are transmitted to the valve element, and a backlash free connection between the valve element and the drive member, the backlash free connection comprising a projection protruding laterally from one of the drive member and the valve element, the projection being received within a recess associated with the other of the drive member and the valve element, the dimensions of the projection and the recess being such that the projection engages the sides of the recess but is spaced from the base thereof, and biasing means urging the projection towards the base of the recess.
As the projection does not engage the base of the recess, engaging only the sides of the recess, and as the valve element and the drive member are biased in such a manner as to urge the projection towards the base of the recess, the cooperation between the projection and the sides of the recess substantially prevents relative axial and angular movement between the valve element and the drive member.
The projection may be defined by an end region of a pin. The pin conveniently extends through an opening formed in the drive member and engages with a recess formed in the valve element, an opposite end of the pin also being received within a recess formed in the valve element. The pin conveniently includes a central region of diameter greater than the width of the recess. Such an arrangement is advantageous in that the pin is held captive and so the backlash free connection will not be broken by, for example, vibrations.
The valve may be of the type of the first aspect of the invention.
REFERENCES:
patent: 48588 (1865-07-01), Poh
patent: 313089 (1885-03-01), Martin
patent: 2202216 (1940-05-01), Madsen
patent: 3349798 (1967-10-01), Allen
patent: 4191213 (1980-03-01), Dolling et al.
patent: 4974636 (1990-12-01), Cogger
patent: 5358213 (1994-10-01), Pilolla
patent: 5524822 (1996-06-01), Simmons
patent: 5595216 (1997-01-01), Pilolla
patent: 5755262 (1998-05-01), Pilolla
patent: 6158465 (2000-12-01), Lambert et al.
Andrus Sceales, Starke & Sawall
Lucas Industries Limited
Rivell John
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