Fluid handling – Diverse fluid containing pressure systems – Fluid separating traps or vents
Reexamination Certificate
1999-06-14
2001-01-30
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Fluid separating traps or vents
C137S415000
Reexamination Certificate
active
06178985
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates to an automatic drain system and apparatus particularly designed for the removal of condensate and contaminants from compressed air systems.
2. Prior Art and Background of the Invention
In compressed air systems it is generally necessary to remove condensate as well as particulate material such as rust and scale to ensure proper operation and avoid corrosion and damage to the systems. To accomplish the removal of condensate various float valve assemblies and systems have been developed and used.
U.S. Pat. No. 3,635,238 to Hankinson et al. discloses an automatic valving device utilizing a dual float control system that can be used to drain condensate from compressed air systems.
Various patents to Cummings or Cummings et al disclose various automatic drain valves and systems for discharging condensate and foreign materials from various pneumatic systems and devices. Such valves and systems are described in U.S. Pat. Nos. 4,444,217; 4,562,855; 4,574,829; 4,779,640; 5,004,004; and 5,014,735.
U.S. Pat. No. 5,080,126 to DeRycke et al. discloses a magnet and float controlled valve to discharge moisture in a compressed air system.
U.S. Pat. No. 5,533,545 to Robinson discloses a drain system utilizing a magnet and float controlled drain system wherein condensate and particulate contaminants are automatically collected and discharged through an air pressure controlled ball valve.
Although the prior art discloses a number of devices and systems for removing moisture from compressed air systems, it will be appreciated that a need exists for a still further improved and efficient system for this purpose.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide an improved drain system for the removal of condensate and particulate contaminants from compressed air systems.
It is another object of this invention to provide a drain system having improved efficiency and characterized by simplicity of design and requiring a minimum of parts.
It is a still further object to provide a drain system and apparatus that is compact in design.
These and other objects are accomplished in accordance with the present invention which provides an automatic drain system particularly adapted for removal of condensate and particulate contaminants from compressed air systems which comprises, in combination, a reservoir having a liquid inlet and a liquid outlet; a float structure comprising a float having a lever arm pivotally attached thereto at a fulcrum point of the lever arm and responsive to the liquid level in the reservoir; an air discharge tube controllably coupled to the lever arm of the float structure for opening and closing the air discharge tube in response to changes in the liquid level in the reservoir; an air cylinder in fluid communication with the air discharge tube; a valve for opening and closing the liquid outlet, the valve being responsively connected to the air cylinder so that the valve is controllably opened and closed by the air cylinder in response to air pressure transmitted from the reservoir through the air discharge tube to the air cylinder in response to changes in liquid level in the reservoir. Preferably, the movement of the lever arm is aided by use of a counter-weight attached thereto at the end opposite the float.
In operation, the liquid inlet of the reservoir is connected to a compressed air system to be drained so that condensate will flow by gravity into the reservoir. A vent port located at the top of the reservoir and also connected to the compressed air system allows the air to escape as the condensate enters. This allows air pressure to equalize and prevents air lock problems. When the float is at its lowest level a seal on the underside of the lever arm rests on the opening (seat) of the air discharge tube and effectively acts as a valve closing the air discharge tube. The lever arm is pivotally connected to the entrance end of the air discharge tube at the side opposite the float. As the condensate fills the reservoir, the float rises, lifting the seal from the seat of the air discharge tube and allowing air to flow through to an air cylinder attached to the outside of the reservoir. As the compressed air enters the cylinder a rod at the other end of the cylinder is forced outward. As the rod moves outward, it forces the ball valve open. As the ball valve opens, the pressure within the reservoir forces the liquid condensate, as well as particulate contaminants, through the passage in the ball valve and out the liquid outlet. As this happens, the liquid level in the reservoir drops and the float lowers. Finally, the float reaches its lowest position and the seal on the underside of the lever arm seals the air discharge tube, thus allowing the cycle to begin again. The excess air pressure that remains in the discharge tube and air cylinder is allowed to escape through a bleed hole. A spring in the air cylinder returns the cylinder to its retracted state and thus the ball valve closes.
In a preferred embodiment, as the float rises in response to a rising liquid level in the reservoir, the lever arm and seal are held in place with the aid of a magnetic force preventing air flow through the air discharge tube until buoyant force on the float is sufficient to overcome the magnetic force. The magnetic force may be created, for example, by a magnet attached to the air discharge tube and a ferromagnetic component integral with lever arms. This allows a greater volume of condensate to collect in the reservoir before the drain part of the cycle begins. Furthermore, when the force of buoyancy is great enough to overcome the magnetic force the seal will be fully lifted instantaneously from the seat and deliver a full flow of air, more than will dissipate through the bleed hole while the ball valve is quickly opened via the extension rod of the air cylinder.
In another preferred embodiment, a weight is attached to the end of the lever arm opposite the float.
In yet another preferred embodiment, two lever arms are employed. Both are pivotally connected to the entrance end of the air discharge tube. The weight is attached to one end of the first lever arm and a seal is attached to the underside of the arm in alignment above the entrance to the air discharge tube. A float is attached to the end of the second lever arm, and is positioned in alignment below the end of the first lever arm. At a point near the float, the second lever arm is tethered, for example, by means of a flexible wire, chain, rope or the like, to the end of the first lever arm that is opposite the end where the weight is attached. The purpose of the second lever arm with float, tethered to the first, is to create a delay in the closing of the air discharge tube as the float lowers. The delay will allow the expulsion of more condensate per cycle.
REFERENCES:
patent: 3635238 (1972-01-01), Hankison
patent: 5417237 (1995-05-01), Stumphauzer et al.
patent: 5687754 (1997-11-01), Nemeth et al.
Cookfair Arthur S.
Michalsky Gerald A.
Ralabate James J.
Robinson Larry P.
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