Ball valve with modified characteristics

Abstract

A valve according to the invention having a disk with a shaped opening and one side interfacing with and conforming to the shape of the exterior of the ball or plug. The disk fits inside the port at the seat area, and is secured by a ring. The ring can be threaded into the connection for the fluid pipe line. Alternatively, the connection can have a groove for an internal retaining ring. The disk is positioned so it interacts with the hole in the ball, in such a way that the desired flow characteristics are accomplished.

Description

RELATED APPLICATIONS[0001]This application is a Reissue of U.S. Pat. No. 6,039,304 which claims priority to U.S. Provisional Patent Application Ser. No. 60 / 062,010 filed Aug. 1, 1997. A divisional U.S. Patent Application Ser. No. 09 / 404,739 remains pending.<?insert-end id="INS-S-00001" ?>FIELD OF THE INVENTION[0002]The present invention primarily pertains to control valves used to control the supply of hot or chilled fluid (especially water) to the heat transfer devices used in the heating / ventilation / air conditioning systems in buildings (commonly referred to as the HVAC system). These control valves are generally operated by actuators, which are connected to the temperature control system. The valves are modulated to any suitable intermediate position, so a flow rate that produces the desired temperature is supplied.BACKGROUND OF THE INVENTION[0003]The flow capacity of the subject control valves must be selected so as to be suitable for each control object. Also, the flow ch...

AI Technical Summary

Benefits of technology

[0007]Accordingly, it is an object of the present invention to provide an improved control valve in which its flow capacity and flow characteristics can be easily changed, without having to take the valve apart. Thereby, the integrity of the valve seals will remain intact, and the time consuming operation of taking the valve apart and reassembling it is eliminated.

[0010]It is still another object of the present invention to provide a control valve which is inexpensive to manufacture and which can be quickly and easily assembled.

[0011]It is still another object of the present invention to provide a control valve which has flow capacity and flow characteristics which can be easily changed without disturbing the integrity of the valve seal.

[0013]In another embodiment of the present invention the disk is spring loaded, so it rests upon the ball. This reduces any unwanted flow that passes between the disk and the ball, so essentially the entire flow through the valve is controlled by the opening in the ball and the opening in the disk.

[0014]A further embodiment comprises a control valve having a disc having a surface facing the ball, wherein the disc surface is concave as described above, wherein the ball valve has a reduced size port. In a reduced port ball valve the largest diameter of the hole through the ball is smaller than the largest diameter of the hole in the port and seat in the valve body. The reduced size port eliminates the risk that the disk moves into the hole through the ball, when the valve is fully open.

[0015]As an alternative, the concave side of the disk can be slightly cantered (one side thicker than the opposed side). This has the effect that the disk only partially rests upon the ball, so any unwanted flow between the disk and ball is minimized when the valve begins to open. The cantered shape makes it possible to use a full ported valve without the risk that the valve will lock up, so it no longer can be operated. (A full ported ball valve has a hole through the ball of the same diameter as the diameter of the port and seat in the valve body.)

Problems solved by technology

Basic ball valves or plug valves have a certain inherent flow characteristic not ideally suited for the above mentioned applications.

The use of reducing couplings and installing a valve with a smaller size than the basic pipe size tends to further distort the valve characteristics.

A significant disadvantage of the plug valve taught in the '580 patent is that the HVAC market is in general very price sensitive, and therefore relatively inexpensive “two piece” ball valves are often used.

This makes it very difficult (indeed, practically impossible) to take the valve apart in order to exchange the seats.

Specifically, if a “two piece” valve is taken apart and reassembled in the field, there is a risk that it may be tightened too little or too much.

This will either cause leakage through the seats, or an excessive torque to operate the valve.

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