WO1994008103A1

WO1994008103A1 - System and apparatus for a pressurized flush toilet

Info

Publication number: WO1994008103A1
Application number: PCT/US1993/009133
Authority: WO
Inventors: Chang Shih-Chih
Original assignee: Shih Chih Chang
Priority date: 1992-09-28
Filing date: 1993-09-27
Publication date: 1994-04-14
Also published as: AU5536594A; JPH073856A; TW241321B; JP2670479B2; KR970007596B1

Abstract

A flush system for a toilet (31) consists of a sealed flush tank (1) which is normally empty, a feed valve (2) connecting the tank (1) to the water supply, and a flush valve (3) for discharging water under pressure from tank (1) to the toilet (31). In use, start button (6) is depressed, admitting water from the supply through valve (3) and check valve (12) into tank (1). Air above the water in the tank (1) is compressed until it reaches supply pressure, closing valve (4). A small amount of water from valve (3) bleeds through port (14) in plug (15), gradually reducing the pressure on plug (15), until pressure in the tank unseats plug (15), thus admitting a pressurized flush into toilet (31).

Description

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION

TECHNICAL FIELD

This invention generally pertains to flush toilets, including an apparatus and process system, to produce an improved and more reliable flush, while using less water.

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION

BACKGROUND ART

The working principle of flush toilets relies on two basic elements, namely the wastetrap and the siphon. The wastetrap consists of a trapway which is constructed by a dam formed by a up-turn flow passage followed by a down turn section. This arrangement prevents the water in the bowl from draining below the top of the dam to form a water pool at the bottom of the toilet bowl between uses. The water pool functions as a liquid seal which isolates the toilet bowl from the downstream waste line and it also receives the dropping waste and prevents direct contact of waste with the toilet bowl surface. The down-turn section of the trapway extends substantially below the bottom of the bowl so that a siphon can be induced at a certain high water flow.

With a conventional toilet, water is released to the bowl which first causes an overflow from the bowl over the waste dam. As the flushing continues, the overflow increases to a critical rate at which a column flow is formed in the down turn section of the trapway. Under this condition a siphon is established. The siphon induces a suction which extracts the waste from the bowl. In fact, all existing flush toilets rely on the siphon for waste extraction. Since the siphon can be established only by a certain high water flow, a high capacity water supply becomes necessary. A domestic toilet delivers the needed high flow by a release of a significant amount of water from a flush tank. The flush tank of a gravity flush toilet is positioned just above the bowl and open to the atmosphere. Currently, the gravity flush toilet is by far the most popular in the U.S. and over the world.

Lately a pressurized flush system was developed for domestic toilets which utilizes the existing pressure energy of the water supply to energize the flushing action. This system consists of a sealed flush tank for collecting pressurized water so as to cause an effective increase of water supply. After a flush, the flush tank is refilled by the water supply automatically. As supply pressure forces water into the flush tank, it compresses the entrapped air inside the tank and causes the tank pressure to increase until it reaches to a predetermined pressure. Then the feed flow is cut off by a pressure regulator and the water and the compressed air is held in the tank until the next flush. Since the volume of the tank and the quantity of entrapped air are fixed, the control of the tank pressure determines the quantity of water per flush.

The pressurized flush system has many advantages over the conventional gravity flush. The initial water discharge velocity of this system is significantly higher than that obtained by gravity flow. The total energy involved in a pressure flush is many times greater than the gravity flush. As a result the pressurized flush establishes the needed siphon almost immediately and it requires far less water for an effective flush.

However, there are a few undesirable characteristics with the existing pressurized flush system. The existing pressurized flush adopts the same conventional concept that stores the water in the tank between uses. This requires the flush tank to be regulated pressurized almost all the time. This causes safety concerns, because a significant amount of energy is constantly stored in the form of compressed air. Extra precautions are needed in the structural design of the flush tank which adds manufacturing costs to the system. Furthermore, the pressurized water in the tank may cause a back flow to the supply system when supply pressure fluctuates which could be a threat to public health. To prevent the backflow from the pressurized tank, a reliable backflow prevention device is required. This again increases the system complexity and manufacturing costs. Another problem with the exiting pressure tank system is that the existing system needs to entrain a fixed quantity of fresh air at each refill of the flush tank, in order to make up the air lost in the previous flush. To control the air entrainment the water flow must be regulated by a rather precise venturi nozzle. This further increases the complexity of the system which translates in installation and maintenance costs. In operation the user needs to open the flush valve under pressure. Due to the large cross-section area of the flush valve and the hydraulic pressure a large force is applied on the flush valve. For user's convenience, it is necessary to reduce the force for valve opening to a manageable level. The existing solution to this problem is to include a pilot valve for actuating the tank flush valve. This again makes the pressurized flush system more complicated and less reliable. As a result, up to now, the pressure tank system has not become very popular in spite of its superior performance.

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION DISCLOSURE OF INVENTION

The main object of the disclosed invention is to provide a new toilet flush system that utilizes the existing pressure energy in the water supply to reduce water consumption and to improve the performance of the toilet. A specific object of the disclosed invention is to eliminate the various disadvantages of the existing pressure tank system such as the safety concerns and the system complexities.

Another specific object of the disclosed invention is to provide a new pressure flush system in which the flush tank is empty between uses and it is pressurized only for a short period just before flush.

Still another specific object of the disclosed invention is to provide a new pressure flush system that is operated with a different and unique flush cycle in which the flush tank is refilled just before the flush. By so doing, it eliminates the safety and back flow concerns of the existing pressure flush system. Still another specific object of the disclosed invention is to provide a new pressure flush system which refills the pressure tank with fresh air automatically after each flush so that it eliminates the need of air entrainment devices from the existing pressure flush system.

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings which form a part hereof:

Figure 1 is a perspective view of a cross-section and cut-away of the toilet system;

Figure 2 is a side-view of a cross-section of one application of my toilet system, at a time when the flush tank is filling with water; and

Figure 3 is a side-view of a cross-section of one application of my toilet system, at a time when the pressure in the flush tank has caused the fill valve to close and water is flowing from the flush tank, through the flush and into the toilet bowl.

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION

BEST MODE OF CARRYING OUT THE INVENTION

The present invention specifies a new and innovative method of and apparatus for flush toilets. The present invention is specifically related to a pressure flush system for toilets. Up-to-date all the existing flush tanks in the existing toilets, including gravity flush and pressure flush, are filled with water between uses. The flush cycle of a conventional toilet is normally started by opening the flush valve of the flush tank. Then, the stored water in the tank discharges to the toilet bowl. After the tank is emptied, the flush valve closes automatically. Then the tank is refilled with water automatically to the predetermined level and the water stays at that level until next use.

The flush cycle, in accordance with the present invention, is completely different from all existing flush toilets. The disclosed invention consists of a sealed flush tank, a feed valve connected to the water supply, a flush valve leading the discharging water to the toilet bowl. The flush tank is empty between uses. A flush cycle starts with tripping open the feed valve. Then the pressurized supply water forces into the flush tank, at the same time, the hydraulic force of the feed water closes the flush valve. The closure of the flush valve entraps a full tank air therein. The incoming water is collected in the flush tank and, the increased water volume compresses the entrapped air inside the tank and causes the tank pressure to increase. When the tank pressure reaches to a predetermined level, the feed valve closes and the flush valve opens automatically. The water is then discharged to the toilet bowl under the pressure of the compressed air which immediately induces a siphon which in turn extracts the waste out of the toilet bowl. Thus, when the user triggers the flush cycle, the flush action does not start immediately, instead, there is short delay which allows the flush tank to be charged. Then, suddenly the flush starts automatically with a powerful water discharge. This flush cycle is conceptually different from all existing toilets.

Referring to Figure 1, the flush tank 1 is a sealed tank for holding water and compressed air. Tank 1 is hydraulically connected to the water supply through a feed valve 2 and a conduit 4 and then to the toilet bowl 31 through a flush valve 3. A preferred toilet bowl design using the present flush system is similar to a conventional siphon jet design which has a jet nozzle 32 at the bottom section of the toilet bowl. In this preferred embodiment, the discharge flow from the flush tank splits into two stream. One stream flows to the rim channel 33 which subsequently discharges to the bowl through the rinsing holes 34. The other stream feeds to the jet nozzle 32 and forms a high speed jet during a flush. A water pool 35 is collected at the bottom of the toilet between uses which serves as liquid seal, and at the same time, as a catcher for the dropping waste. Between uses, the feed valve 2 is closed, the flush tank 1 is empty and the flush valve 3 is open.

Figure 2 shows the details of the flush system, in accordance with the present invention. A push on the start button 6 will push the plug 4 away from the valve seat 5 and cause the feed valve to open. In the open mode the valve plug 4 is no longer subjected to the hydro-static pressure of the supply water. The feed water enters the flush tank through a cylinder means 11 and through the check valve 12. At the same time the pressure of the feed water pressurizes the cylinder means 11 and thereby closes the flush valve 3 by pushing the flush valve plug 15 against the flush valve seat 13. The closure of the flush valve entraps a full tank of air therein. Then the water, which is under the pressure of the supply line, starts to flow into the flush tank 1. The incoming water gradually compresses the entrapped air as it is collected in the tank.

Due to the existence of a fixed relationship between the tank pressure and the water quantity in the tank, the tank level can be controlled by the tank pressure. In this preferred embodiment the feed flow is shut off at a predetermined tank pressure by a pressure switch means incorporated in the feed valve 2. When the pressure in tank 1 reaches to a predetermined value, the hydraulic force applied on piston 8 overcomes the spring force and consequently causes the feed valve 2 to close. When valve 2 is closed, the pressure in cylinder 11 is no longer sustained by the incoming feed flow and the cylinder 11 is depressurized by a bleed flow through the narrow flow passage 14 which communicates with the external low pressure region. The depressurization of cylinder 11 causes the plug 15 to retract and to disengage from the valve seat 13 as shown in Figure 2. This opens the flush valve 3 and allows the tank water to discharge to the toilet bowl.

The discharge flow, which is accelerated by the pressure of the compressed air, establishes a siphon almost immediately which extracts the waste collected in the bowl until the toilet bowl is nearly empty. Then, the siphon breaks and the bowl remain empty momentarily.

A flush toilet is required to be designed such that its waste trap is automatically refilled after each flush. This is necessary to seal the waste drain line and to get ready for the next use. A preferred solution, in accordance with the present invention, is to slow down a portion of the water discharge cycle at the end of the discharge so that the last portion of the discharged water remains in the toilet bowl after the siphon break. There is a short standpipe 21 upstream the flush valve 3. It is so arranged that the volume in the flush tank below the upper end of the standpipe is sufficient for refill of the water pool. There are a number of flow orifices 23 near the bottom of the stand pipe. When the water level in tank 1 is dropped to the upper end 22 of the standpipe during a discharge, the flow path is restricted by the small orifices 23 which significantly reduce in flow rate of the discharge. The slow water discharge can no longer sustain the siphon flow in the which consequently causes the siphon to break. The water of the slow discharge is than collected in the bowl and it refills the water pool.

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILET

DESCRIPTION

INDUSTRIAL APPLICABILITY

The way in which the invention can be exploited in industry and the way in which it can be made and used, is obvious from the description and the nature of the invention. Toilets are literally used around the world and most of the toilets are unreliable and inefficient. This toilet system will allow more reliable toilets to be manufactured and will allow toilets to be installed such that massive savings of water can be realized world-wide.

Claims

SYSTEM AND APPARATUS FOR A PRESSURIZED FLUSH TOILETDESCRIPTION CLAIMSI claim

1. A toilet apparatus, comprised of: a. a flush tank which is air tight and water tight; b. a water supply, which is operatively connected to an interior of a flush valve, with a flush tank fill valve controlling the flow of water between the water supply and the interior of the flush valve; c. a manual means to open the flush tank fill valve and allow water to flow from the water supply to the interior of the flush valve; d. an opening between the interior of the flush valve and the flush tank, said opening being controlled by a pressure switch that closes when the pressure in the flush tank exceeds the pressure in the interior of the flush valve, and said pressure switch which, when open, allows the flow of water from the interior of the flush valve into the flush tank, the flow of which compresses entrapped air in the flush tank; e. a toilet bowl which is operatively connected to the flush tank; and f. the flush valve controls the flow of water between the flush tank and the toilet bowl, closing when water flows from the water supply and opening when the flow of water from the water supply stops, and the opening of the flush valve allows water to flow from the flush tank to the toilet bowl, thereby removing waste from the toilet bowl;

such that when the pressure differential between the flush tank and the interior of the flush valve reaches a pre-determined value, the flush tank fill valve closes and the flush valve opens.

2. A toilet apparatus as recited in claim 9, wherein the flush valve is comprised of: a. a cylinder means with an interior which receives water from the water supply, and which has a pressure flow gate between its interior and the flush tank, said pressure flow gate is open when pressure within the interior of the cylinder means is greater than pressure within the flush tank, and closed when pressure within the flush tank exceeds pressure within the interior of the cylinder means; b. a piston means fitting within said cylinder means, which closes the flush valve when it extends from the cylinder means and opens the flush valve when it retracts into the cylinder means, and which is subject to force from within the flush tank which pushes the piston means causing it to retract into the cylinder means; and c. a small opening which allows air and water flow between the interior of the cylinder means and the toilet bowl;

such that once the force within the flush tank subjects the piston means, and consequently the flush tank fill valve, to a pre-determined force, the flush tank fill valve closes and stops the flow of water from the water supply, and since water flows through the small opening to the toilet bowl, pressure within the cylinder means becomes less than pressure within the flush tank, which causes the piston means to be pushed into the cylinder means, thereby opening the flush valve.

3. A process for flushing a toilet, which comprises the following steps: d. maintaining an air-tight flush tank empty preceding the start of a flush cycle; e. starting the flush cycle by triggering water to feed to the flush tank from a pressurized water supply source, which entraps and compresses the air in the flush tank; f. causing the pressurized water supply to stop flowing once a predetermined internal pressure is present in the flush tank; g. discharging the water in the flush tank to a toilet bowl, utilizing pressure accumulated in the flush tank from the compression of the entrapped air and water, whereby the water discharged from the flush tank extracts waste out of the toilet bowl; and h. the water flow extracting waste out of the toilet bowl refills a waste trap in the toilet bowl, such that the flush toilet is then ready to go through another cycle.

4. A process for flushing a toilet as recited in claim 11, and in which the pre¬ determined internal pressure achieved in the flush tank is pre-determined in relation to the amount of water desired for flushing.