This invention relates to the art of fluid pressure regulating valves wherein a valve element is diaphragm actuated to control the flow of fluid through the valve and, more particularly to an improved valve element operating arrangement for a diaphragm-operated pressure regulating valve.
It is well known to provide fluid pressure-regulators which operate in accordance with the pressure of fluid acting against a flexible diaphragm between valve housing components to provide a pressure chamber on one side of the diaphragm and a chamber vented to atmosphere on the other. The pressure chamber includes an inlet orifice or port for fluid under pressure from a source and an outlet passage for the flow of gas to a point of use such as, for example, a gas-operated cooking grill. A valve unit controls the flow of fluid through the inlet orifice to the outlet opening and, most often, the valve unit comprises lever arm pivotally mounted in the pressure chamber and having an end connected to the diaphragm for the later to pivot the arm about its axis during operation of the valve. The other end of the lever arm carries a resilient sealing member or valve element which, in response to pivotal displacement of the lever arm, engages and disengages the inlet orifice to respectfully close and open the latter to the flow of fluid into the pressure chamber from the source. Regulating valves of the foregoing character also include a relief valve arrangement by which excessive back pressure into the pressure chamber from the point of use is vented to atmosphere.
The problems encountered in connection with pressure regulators employing the lever arm concept include an undesirably large housing or envelope and therefore a higher than desired cost of manufacturing. In particular in this respect, the length of the lever arm required to obtain the necessary mechanical advantage with respect to controlling the flow of liquid at a given supply pressure requires a large housing or envelope, and the size of the latter increases as the supply pressure increases requiring a larger capacity inlet orifice and liquid flow and a high lever ratio to assure appropriate control of the flow. It follows that any increase in the size of the valve housing increase the cost-thereof as well as the overall cost of the regulating valve. A further problem encountered in connection with lever operated valve elements is performance limitations resulting from the opening and closing arc of the sealing element relative to the inlet orifice and which arc is determined by the length of the lever arm between the pivot axis thereof and the valve element thereon. More particularly in this respect, the displacement of the sealing member or valve element along an arcuate path relative to the inlet orifice makes it extremely difficult to obtain and to then maintain proper seating of the sealing element relative to the orifice. Yet a further problem encountered in connection with pressure regulating valves using the lever concept results from turbulent flow conditions resulting from the fluid flow through the inlet orifice to the pressure chamber and which turbulence causes the lever arm to vibrate and/or oscillate during valve operation causing fluctuating gas flow to the point of use.
In accordance with the present invention, an improved valve element operating arrangement is provided for a diaphragm-operated pressure regulating valve which eliminates the use of a lever and, in connection with a pressure regulating valve of the same capacity using the lever concept, considerably reduces the size of the valve housing and thus the cost thereof as well as the overall cost of the regulating valve while increasing performance characteristics relative to lever operated valves. More particularly in accordance with the invention, the foregoing attributes are achieved through the use of a valve element which is coaxial with and axially displaceable relative to the inlet orifice and the opening and closing displacement of which is controlled by a ball and cam actuating unit which is coaxial with the inlet orifice and operates in response to displacements of the diaphragm. The ball and cam unit provides the necessary mechanical advantage which in turn provides the operating force against the valve element and the fluid supply pressure for closing the inlet orifice. By having all of the component parts of the actuating unit coaxial with and linearly displaceable relative to the axis of the inlet orifice, the housing or envelope for the valve is considerably reduced in size, and thus cost, relative to a valve of the same capacity employing the lever concept. Moreover, linear displacement of the valve element relative to the inlet orifice advantageously provides for a resilient sealing member on the valve element to engage the orifice transverse to the axis thereof, thus optimizing the obtaining and maintaining of a proper seating of the sealing element against the inlet orifice.
In accordance with another aspect of the invention, the flow of fluid from the inlet orifice to the outlet passage of the valve is through trim orifices, each of which is slightly smaller in diameter than the inlet orifice and which trim orifices function together with the inlet orifice to promote uniform flow, to eliminate vibration and to provide lockout pressure requirements. More particularly in this respect, the trim orifices create a positive pressure or force against the ball and cam components of the actuating unit to eliminate clearances therebetween and thus undesired relative movement therebetween. By reducing lockout pressure, an increase in diaphragm bias spring loading is obtained which results in increased regulated output flow, and this further contributes to a smaller sized regulator and a higher flow rate.
It is accordingly an outstanding object of the present invention to provide an improved diaphragm-operated valve element actuating arrangement which enables decreasing the size and cost of a diaphragm-actuated fluid flow pressure regulating valve in comparison to such valves employing a diaphragm actuated pivotal lever for displacing the valve element relative to the inlet orifice of the valve.
Another object is to provide a diaphragm actuated pressure regulating valve in which the valve element is coaxial with and axially displaceable relative to the inlet orifice of the valve and wherein the valve element actuating unit is coaxial with the valve element and operated by displacement of the diaphragm.
A further object is the provision of a diaphragm actuated pressure regulating valve of the foregoing character which is structurally simple, of minimal size with respect to a given flow capacity, and which costs less to manufacture than diaphragm actuated fluid flow pressure regulators heretofore available.
Yet a further object is the provision of a diaphragm actuated fluid flow pressure regulating valve of the foregoing character in which the diaphragm operated valve element actuating unit is comprised of ball and cam components operatively interconnected with the valve element for controlling displacement thereof in response to displacements of the diaphragm.