| 摘要 |
<p>The present invention concerns a means for controlling and/or measuring the flow of a running fluid, wherein the throttling of the flow is controlled utilizing the fluid's own differential pressure arising from the flow. The valve comprises a cover provided with a flow aperture, a main valve disc and control means consisting of a cylinder volume/piston assembly, the movement of said piston being connected to the main valve disc, and wherein the cylinder volume has been connected by a first opening (d1 min ) to the high pressure side and by a second opening (d2 min ) to the low pressure side so that the ratio of the areas of the openings is adjustable. The means comprises at least one sensing member by the aid of which the position of a part of the cylinder volume/piston assembly moving axially in the direction of the flow is measured; a data processing unit, to which the signal from the sensing member is conveyed after appropriate processing; a memory unit, in the first part of which have been stored data concerning the characteristic curve of the valve or equivalent, from which based on the signal from said sensing element, with the aid of the data processing unit, the variations of volumetric flow and or pressure can be calculated, and in the second part of said memory unit being stored the desired values of the volumetric flow and/or pressure, with which the calculated values mentioned before are compared; and at least one actuator by the aid of which the ratio of areas of the openings (d1 min , d2 min ) is adjustable for realizing the desired volumetric flow and/or pressure.</p> |
