1. Field of the Invention
The present invention relates to a pressurized water closet flushing system that minimizes water usage incident to flushing of a toilet yet maximizes the efficiency of effluent transport.
2. Related Art
The herein disclosed pressurized water closet flushing system represents an improvement over the system disclosed in my U.S. Pat. No. 4,233,698 issued Nov. 18, 1980 and is a continuation of my application Ser. No. 08/457,162, filed Jun. 1, 1995 abandoned.
Water conservation is an environmental problem that has resulted in strict controls being placed on domestic water usage in many areas of the country. Pressurized water closet flushing systems make a significant contribution to water conservation in that they exhibit relatively low water consumption coupled with high effluent transport efficiency. Known systems generally consist of a water supply group, an accumulator vessel, a flush valve and a flush control. The aforesaid components are generally installed internally of a water closet and are energized by water pressure from a fresh water supply system.
A complete flush cycle consists of a water fill phase and a water discharge phase. In the fill phase of the cycle, supply system pressure forces the water into the accumulator vessel. As the water level rises in the accumulator vessel, air contained therein is compressed. When the pressure of the compressed air in the accumulator vessel equals that of the fresh water supply, flow of water into the accumulator vessel ceases and the system is conditioned for the water discharge phase of operation. When the flush control is actuated, the water discharge phase commences and the compressed air in the accumulator vessel pushes the stored water into the water closet bowl at high velocity, flushing waste therefrom with minimum water consumption.
The function of the accumulator vessel is to store both water and potential energy in the form of compressed air. For a given line pressure, the volume of the accumulator vessel determines the maximum discharge energy available.
The water closet flushing system of the present invention exhibits a substantial increase in discharge energy over known systems without a corresponding increase in water consumption. Discharge energy is maximized by increasing the volume and therefore the total potential energy of the compressed air charge above the water in the accumulator vessel while water consumption is minimized by positive closing of an improved flush valve.
The improved flush valve features a novel balanced piston that divides a flush valve cylinder into upper and lower chambers. As water enters the accumulator vessel, in the fill phase of the flush cycle, compressed air flows from the lower chamber defined by the piston through an air transfer orifice in the piston into an upper chamber of the cylinder above the piston. The fill phase of the cycle continues until a pressure balance is achieved between pressure in the accumulator and line pressure. The flush control is connected to the upper chamber of the flush valve cylinder. When the flush control is opened, the water discharge phase of the flush cycle is initiated by venting the compressed air in the upper chamber of the cylinder creating a pressure differential across the piston allowing the piston and flush valve thereon to move upwardly allowing water in the accumulator vessel to be discharged at high velocity into the water closet bowl.
Closing or downward movement of the flush valve piston is initially resisted by a partial vacuum that is created within the upper chamber of the cylinder above the piston due to initial downward movement thereof. The flush valve piston remains suspended with the flush valve thereon in the open condition until sufficient air passes from the accumulator to the lower chamber of the flush valve cylinder thence upwardly through the transfer orifice in the piston into the upper chamber of the cylinder to reduce the pressure differential across the piston, allowing the flush valve piston and flush valve to return to the closed position under the bias of the flush valve return spring.
The aforesaid operation of the flush valve is insured by an improved air induction system that provides for replenishment of air lost in each flush cycle and lost due to absorption of air into the stored water. Moreover, the air induction system is self-limiting and the accumulator vessel cannot be overcharged with air, e.g., become xe2x80x9cair-logged.xe2x80x9d
In accordance with yet another feature, an improved vacuum breaker acts as a safety device that precludes contaminated water in the toilet bowl from being siphoned into the accumulator vessel and then into the fresh water system. In the event that a negative pressure develops within the fresh water supply system resulting in a relatively higher pressure in the accumulator vessel than in the water supply system, water contained within the vessel will flow backwards reducing the pressure within the vessel. When the internal pressure within the vessel falls below ambient pressure, the vacuum breaker valve will open and admit outside air into the vessel breaking the vacuum and precluding waste from the water closet bowl from being pulled into the vessel. Placement of the vacuum breaker above the flush valve piston precludes creation of a vacuum above the piston in the event air in the accumulator vessel is fully expanded which could restrict proper closure of the flush valve.
Advantages of the herein disclosed system over prior systems are greater operational reliability, higher efficiency and lower manufacturing cost.