Fluid handling – Convertible
Reexamination Certificate
2002-10-02
2004-03-23
Bastianelli, John (Department: 3754)
Fluid handling
Convertible
C251S292000
Reexamination Certificate
active
06708720
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a valve accessory, and in particular to an adaptor for a valve actuator.
2. Summary of the Prior Art
Valves, particularly industrial valves, are usually opened and closed by valve actuators. Typically, a valve has a rotational control stem which opens the valve mechanism when it is rotated one way and closes the valve when rotated the other. By convention, the direction of opening is usually anticlockwise looking along the control stem towards the valve mechanism.
Rotation of the control stem is carried out by the actuator, usually in response to a control signal. The actuator has a rotational drive and this engages with the control stem to rotate the control stem. The actuator housing is usually attached to the valve itself, at a part other than the control stem, in order more efficiently to generate torque to rotate the control stem with respect to the rest of the valve.
The present invention is particularly concerned with part turn actuators in which the rotational drive of the actuator has a limit of rotation of less than a complete revolution, i.e. less that 360°.
For satisfactory operation and to minimise leakage, valves are manufactured with small dimensional tolerances. This has led to some of their dimensions being standardized. This is the case in terms of the dimensions of the interface between a valve and a part turn actuator. The relevant standards are ISO 5211 (reference number ISO 5211:2001 (E), published Feb. 15, 2001) and DIN 3337 (published September 1985). The contents of these publications are incorporated herein by reference. Where relevant in this specification, they will be referred to together as ISO 5211/DIN 3337, or separately, as appropriate. Devices which are described as non-ISO 5211/DIN 3337 are devices which do not conform either to ISO 5211 or to DIN 3337.
To be directly attachable to a valve of standard dimensions, an actuator must also have standard dimensions. An advantage of the standardized valve/actuator assembly is that a bracket and coupling usually need not be used since the actuator can be directly mounted onto the valve. Of course, manufacture of an entire actuator in accordance with international standardized dimensions places restrictions on the actuator. Furthermore, for an existing actuator design standardisation often requires extensive redesign of the whole actuator which is expensive. Still further, the adoption of such standards can make existing, otherwise satisfactory actuators and actuator designs obsolete.
SUMMARY OF THE INVENTION
In a general aspect, the present invention provides an adaptor for mounting a non-ISO 5211/DIN 3337 actuator to an ISO 5211/DIN 3337 valve.
Preferably, in a first aspect, the present invention provides a valve actuator adaptor having a body with first and second mounting surfaces, the adaptor having an aperture extending through the body, the aperture being open at each mounting surface, the first mounting surface having valve attachment points arranged around its aperture in accordance with ISO 5211/DIN 3337, the second mounting surface having valve actuator attachment points not in accordance with ISO 5211/DIN 3337, and a coupling link locatable in the aperture, a first end of the coupling link having a first surface shaped for engagement with a valve rotational control means and a second end of the coupling link having a second surface shaped for engagement with an actuator rotational drive means, the coupling link being rotatable within the aperture;
wherein the valve attachment points of first mounting surface comprise holes extending from said first mounting surface to an exposed third surface intermediate along the axial length of the adaptor, the holes being arranged to receive screws or bolts for securing the adapter to the valve, the third surface having recesses therein around said holes, the walls of the recesses being shaped to prevent rotation of the head of said screws or bolts or nuts mounted on said bolts.
Preferably, in a second aspect, the present invention provides a method of assembling a valve arrangement including the step of mounting a non-ISO 5211/DIN 3337 actuator in relation to ISO 5211/DIN 3337 valve by attachment of an adaptor between the valve and the actuator.
Preferably, in a third aspect, the present invention provides a method of modifying a valve arrangement, wherein the valve arrangement includes an ISO 5211/DIN 3337 valve which is operable via an actuator, the method including the step of mounting a non-ISO 5211/DIN 3337 actuator in relation to the valve by attachment of an adaptor between the valve and the actuator.
In another general aspect, the present invention provides the assembly comprising a valve actuator adaptor having a mounting surface with valve attachment points arranged in accordance with ISO 5211/DIN 3337, with an actuator and a valve mounted thereon.
The valve actuator attachment points are arranged around the aperture opening on the second mounting surface not in accordance with 150 5211/DIN 3337.
Preferably, the valve attachment points are valve attachment holes formed in the body of the adaptor, each valve attachment hole opening at the first mounting surface. The actuator attachment points are preferably arranged around the aperture opening at the second mounting surface. Preferably the actuator attachment points are actuator attachment holes formed in the body of the adaptor, each opening at the second mounting surface. More preferably, one of the valve attachment holes is offset from any of the actuator attachment holes. This in the sense that the principal axis of the valve attachment hole does not coincide with the principal axis of any of the actuator holes (although these axes may be parallel). Even more preferably, all of the valve attachment holes are offset from all of the actuator attachment holes. Stated in an alternative way, preferably none of the valve attachment holes is in line with any of the actuator attachment holes.
This arrangement may allow the depth of one or more of the valve attachment holes to overlap with the depth of one or more of the actuator attachment holes but wherein none of the holes, preferably, is continuous with another. Therefore, for a given hole depth, the axial length of the body of the adaptor can be shorter than if the holes were in line. This is particularly the case where each hole is open only at one end. In that case, the holes may be tapped to engage with a screw thread of an attachment screw or bolt.
One function of the adaptor is usually to allow torque to be transmitted from the actuator to the valve. Reduction in the axial length of the adaptor (as discussed above) can give rise to more efficient transmission of torque from the actuator to the valve. Typically, therefore, the actuator includes a torque transmission coupling, which is discussed is more detail below. It is usually undesirable to transmit relatively high torques over long axial torque transmission couplings since the longer the transmission coupling, the more elastic “twist” it has.
In the case where one or more of the valve or actuator attachment holes is open at both ends (for example, open at both the first mounting surface and at the second mounting surface) then the overlap (referred to above) of one hole with another can be total. As an example, for attachment of the adaptor to a valve, attachment means such as a screw, bolt or similar may be passed along the length of the valve attachment hole to the valve and tightened from the end of the hole which is not adjacent the valve, i.e. from the second mounting surface end. As will be clearly understood, another example could be of attachment of the adaptor to an actuator via an actuator attachment hole.
The valve attachment holes may be radially offset from the actuator attachment holes. Additionally or alternatively, they may be circumferentially offset from each other. Use of the words “radial” and “circumferential” imply that the adaptor has substantially circular, or at least roun
Bastianelli John
Kinetrol Limited
Larson & Taylor PLC
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