| TITLE OF THE INVENTION ΛBATH WATER REUSING SYSTEM DRIVEN BY SUPPLY WATER PRESSURE" Claims The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: Claim 1 - In a bath grey water reusing system, the combination of a small size hydraulic rotating turbine and a small size hydraulic rotating pump, coupled through a common rotating shaft, forming a single device used to extract energy from water being supplied by the water utility system and' simultaneously use that energy to pump recovered bath grey water to a higher level of gravitational potential energy. Claim 2 - In a bath grey water reusing system, the combination of the device defined in Claim 1 with i) a grey water accumulation tank located at a lower gravitational potential energy level and used to collect grey water from the bath only by action of gravitational force, and, ii) a grey water storage tank located at a higher gravitational potential energy level and used to store the grey water pumped from the grey water recovering tank only by action of the device defined in Claim 1. Claim 3 - In a bath grey water reusing system, the combination of the device defined in Claim 1 with a by-pass valve, to allow the regulation of the fraction of utility water flowing into the turbine side of the device or bypassing it, and thus allowing the adjustment of the amount of bath grey water being pumped and the water pressure available in the shower. |
1. Technical Field
- Grey Water Reuse
- Water Supply and Sanitation
2. Background Art
- Hydraulic turbo machines
- Fluid mechanics
3. Disclosure of Invention
The Problem:
Water is an essential element required to satisfy the most basic human needs. The demographic explosion and economic development of human societies in the last century have put our planet's resources under stress and water scarcity is nowadays one of the major problems that humankind is dealing with.
Millions of persons, mainly those in the wealthier countries, continue to neglect the problem and to behave as if this vital resource is still abundantly available for all in quantity, as well as in quality, daily making a reckless use of clean potable water.
Since the global water cycle has shown insufficient capacity to adapt to the increase in water consumption expected to occur worldwide within the next decades, it is certain that many societies will only survive in the long term if water use becomes more efficient than it is today.
For instance, everyday a massive amount of domestic bath grey water 1 is wasted worldwide, although it has enough quality for many other uses that end up by consuming clean potable water from the utility system. From a Human perspective, it is inconceivable that while millions of human beings hardly have access to potable water to satisfy their thirst, so many other millions are simply flushing their toilet waste using high quality potable water.
Many attempts have been made by inventors to enable the reuse of bath waste water in less demanding uses, as for instance in toilet flushing, but failed to succeed due to lack of cost- effectiveness, over complexity or energy inefficiency characterising those inventions. Simply there are no technical solutions available today to enable an energy and cost-effective way for reusing bath grey water in toilet flushing. This is the problem addressed by the invention described next.
1 The expressions "grey water" and "waste water" are used throughout this document with the same meaning and refer to water from baths, which has been used and is considered to be only mildly dirty. The Invention:
The invention 2 presented in this PCT request consists of a system that allows a cost effective and energy efficient way to reuse bath grey water in toilet flushing, avoiding or reducing the consumption of clean water that would otherwise be required for that end. The cost effectiveness is achieved by a simple design that allows simultaneously a low initial cost and a low running cost of the system.
Domestic water is supplied by water distribution companies in urban areas at pressures typically around 4 bar. This pressure is enough to elevate water by several dozens of meters. This means that the energy contained in the water supplied by water utilities may possibly be converted into work, as for instance for the elevation of grey water. The invention explores this possibility.
The core of the invention is a "Micro Hydraulic Turbine-Pump" (MHTP) component, which basically consists of a small hydraulic turbine coupled to a small hydraulic continuous rotating pump through a common rotating shaft, being these rotors located in separate casings.
Regarding the working principle, the MHTP is somehow comparable to a turbo-compressor used in car engines, but in this case the working fluid in the turbine side is clean water supplied by the water utility, while the working fluid in the pump side (analogous to the compressor in car engines) is grey water recovered from the bath taken by an individual user.
The purpose of the MHTP is to extract part of the energy contained in the water being supplied by the water utility system 3 (at a given minimum pressure and flow) and use that energy to pump part of the bath grey water to a "Grey Water Storage Tank" (GWST), which is located at a higher gravitational energy level.
When the user opens the shower valve (tap), the water supplied by the water utility system is firstly routed to the turbine side of the MHTP, transferring energy to the turbine. After leaving the turbine, although with less energy content than before, the utility water flows to the shower and is consumed by the user in a shower bath.
After being used in the bath, the resulting grey water would normally flow to a draining pipe through the action of gravitational force and would then follow directly to the sewer system. In this case, however, the grey water resulting from the bath is collected in a "Small Regulation Tank" (SRT), which is located at a lower level than the bath tub.
The SRT is connected to the pump side of the MHTP so that the accumulated grey water is pumped from the SRT to the GWST at the same time that clean water from the utility system is being consumed. The pump is driven by the turbine side of the MHTP, since these two rotors (turbine and pump) of the MHTP are coupled through a common rotating shaft.
The purpose of the SRT is to allow the accumulation of a minimum amount of grey water in order to facilitate the pumping process. The SRT is also connected to the draining pipe, in a way that allows any excess grey water to flow normally to the sewer.
Before entering the pump side casing of the MHTP, the recovered grey water coming from the SRT first passes through a "Grey Water Filter" (GWF) and is filtered in order to avoid the accumulation of dirt in the pump side of the MHTP, which could otherwise affect its mid-term operating efficiency
2 The expressions "the invention" and "the system" are used throughout this document with the same meaning and refer to the invention to which the applicant is requesting a patent.
3 The expression "water utility system" used throughout this document refers to the water supply infrastructure of the local water supplier company (water distribution company), which supplies clean (and eventually potable) water to the individual consumer and is located upstream of the water consumption and of the invention application. and durability. The GWF is designed to allow easy cleaning by the end-user without using any tools.
The MHTP also integrates a "By-Pass Valve" (BPV), so that the user may regulate the fraction of utility water flow going into the turbine side of the MHTP or bypassing it. The regulation of the amount of utility water flowing into the turbine side of (or bypassing) the MHTP allows the user to adjust the amount of pumped bath grey water and the water pressure available in the shower. In other words, increasing the amount of utility water passing through the MTHP turbine will have as a consequence a larger amount of grey water being pumped to the GWST and, at the same time, a lower water pressure available in the shower.
The BPV thus allows the establishment of a compromise between the amount of grey water recovered and the comfort of use of the shower. It also allows the user to easily stop using the system at any time, by simply bypassing all the water being supplied by the water utility system.
The GWST will stock the recovered grey water until it is needed to fill in the toilet flush tank. It is designed in a way that allows any excessively recovered grey water to flow normally to the sewer and is equipped with a "Discharge Valve" (DV) that allows the user to completely empty the GWST whenever that may become necessary (e.g. for periodic cleaning or dismantling).
When water becomes necessary to refill the toilet flush tank, the grey water stored in the GWST flows by action of gravity to a "Water Source Selection Valve" (WSSV), which has the purpose of selecting the water source to be used to refill the existing toilet flush tank. The WSSV guarantees that priority is always given to the grey water coming from the GWST whenever it is available. When no grey water is available in the GWST, the WSSV allows clean utility water to refill the toilet flush tank. This way the refill of the toilet flush tank is guaranteed in all situations.
The WSSV may be designed as a water float valve type, similar to those used in toilet flush tanks. When a determined minimum level of grey water is available in the WSSV tank, the float valve obstructs the flow of the utility water. When the grey water level in the WSSV tank falls below the determined minimum level (meaning there is no grey water available to refill the toilet flush tank), the water float valve opens and allows the flow of the utility water to the toilet flush tank.
Depending on the capability of the MHTP to pump air coming from the SRT (e.g. in a dry start-up of the system), the system may require the use of a non-return valve in order to assure that the pipe between the SRT and the MHTP is always filled with grey water. However this non-return valve may be avoided if the design of the pump allows it to operate in dry mode.
Advantageous Effects of the Invention:
This invention is characterised by the following unique advantageous features:
1. The use of part of the energy contained in the water supplied by the water utility system as the only external source of energy required to collect, store and reuse bath grey water in individual applications;
2. The use, in individual applications, of a small scale hydraulic turbine coupled to a small scale hydraulic continuous rotating pump through a common rotating shaft, forming a "micro hydraulic turbine-pump" device that allows energy transfer from clean water being supplied by the water utility system to the pumping of recovered bath grey water;
3. Pulsation-free bath water flow achieved by the smooth transmission of energy from the clean water being supplied by the water utility system to the recovered bath grey water pumping, which is made possible by the use of the rotating turbine and rotating pump configuration;
4. Unprecedented combination between design simplicity and operating efficiency when compared to the former inventions aiming at the same goal, enabling a compact, energy efficient and low-cost solution for bath grey water reuse in individual applications and gathering therefore the necessary conditions to enable the deployment of grey water reuse in wide scale with the potential for a significant environmental and social impact at global level.
4. Brief Description of the Drawings
The document "PCT Request - Drawings", which is also part of the PCT request presented by the applicant regarding the invention, includes the following 2 drawings:
■ Drawing 1 - System Components and Working Principle
Figure 1 in Drawing 1 presents the integration of the components included in the system, as well as the system's working principle.
The mains components of the system are the following (numbered as indicated in Figure 1):
1. Micro Hydraulic Turbine-Pump (MHTP)
2. By-Pass Valve (BPV)
3. Small Regulation Tank (SRT)
4. Grey Water Filter (GWF)
5. Grey Water Storage Tank (GWST) - 6. Discharge Valve (DV)
7. Water Source Selection Valve (WSSV)
Clean water supplied by the local water utility at a given pressure flows through the turbine side of the MHTP, transferring energy to the turbine.
The MHTP integrates the BPV, so that the user may regulate the fraction of utility water flow going into the turbine side of the MHTP or bypassing it.
After leaving the MHTP turbine, although with less energy content than before, the utility water flows to the shower and is used by the consumer in the shower bath.
The grey water resulting from the bath is collected in the SRT, which is located at a lower level than the bath tub.
The SRT is connected to the pump side of the MHTP so that the accumulated grey water is pumped to the GWST by the MHTP pump side (which is driven by the turbine side of the MHTP since the turbine and the pump are coupled through a common rotating shaft).
Before entering the pump side casing of the MHTP, the recovered grey water is filtered in the GWF.
The GWST will stock the recovered grey water until it is needed to fill in the toilet flush tank. Excess grey water flows to the sewer. The DV equipping the GWST allows the user to completely empty the GWST whenever that may become necessary. The WSSV guarantees that priority is given to grey water over utility water, whenever there is the need to fill in the toilet flush tank and grey water is available in the GWST. The WSSV may be designed as a water float valve type, similar to those used in toilet flush tanks, integrated in a small water tank. When a determined minimum level of grey water is available in the WSSV tank, the float valve obstructs the flow of the utility water. When the grey water level in the WSSV tank follows below the determined minimum level (meaning there is no grey water available to refill the toilet flush tank), the water float valve opens and allows the flow of the utility water to the toilet flush tank.
- Drawing 2 - "Micro Hydraulic Turbine-Pump" (MHTP) Working Principle
Figures 2, 3 and 4 in Drawing 2 present different views of a schematic of the Micro Hydraulic Turbine-Pump component (which is the core of the invention), as well as its working principle. The final dimensions and accurate design of each sub-component in the MHTC will be subject to optimisation in the products to be developed under the patent being required. For instance, the turbine and pump diameters are represented in Drawing 2 as being equivalent, which may not be the case in the optimised and materialised systems.
The mains sub-components of the MHTP are the following (numbered as indicated in Drawing 2):
1. Turbine Rotor (TR)
2. Turbine Casing (TC)
3. Turbine Casing End Cover (TCEC)
4. Common Shaft (CS)
5. Pump Rotor (PR)
6. Pump Casing (PC)
7. Pump Casing End Cover (PCEC)
8. Inter-casing Sealing (ICS)
Clean water supplied by the local water utility at a given pressure flows through the turbine side of the MHTP, transferring energy to the turbine rotor and consequently to the shaft and to the pump rotor. The pump rotor transfers energy to the grey water recovered from the bath and pumps it to a higher level. For illustration purposes Figure 2 considers the application of a flexible impeller pump type. However different pump designs, as well as turbine designs, may be tested before the final product is defined.
5. Mode for Carrying Out the Invention
In order to develop the invention, the following tasks should first be performed:
1. Design the MHTP component - This should be performed by taking into consideration the utility water supply conditions, the bath grey water recovering and storing conditions, the possible use of currently existing components (if appropriate and allowing cost- effectiveness);
2. Design the remaining system components - This should be performed by taking into consideration the system operational logic, the toilet flush system operating conditions;
3. Simulate the system operation and estimate expected water savings;
4. Estimate the manufacturing cost and analyse the cost effectiveness of the system;
5. Estimate the market potential; 6. Estimate the impact caused by a large scale deployment of the invention.
After a successful demonstration of the working principle of the system through a demonstration prototype, the final product should be obtained by optimising the issues that may be critical to its success in each market segment, in order to achieve the necessary efficiency, cost effectiveness and aesthetical appeal that the final customer will require. This shall be achieved by the optimisation of the hydraulic efficiency of the MHTP, the minimisation of the manufacturing and running costs and of the periodic maintenance requirements. Different turbine designs and pump designs shall be tested before the final design is defined.
6. INDUSTRIAL APPLICABILITY
The invention addresses an application that is present all over the world and therefore its technical potential Ts considerable.
With exception to the "Micro Hydraulic Turbine-Pump" (MHTP) component, most of the system may be assembled using components and materials that are either available nowadays or may be easily manufactured by adapting and optimising existing components:
■ All piping between components may be performed using standard pipes currently available in the market;
■ All water tanks used in the system may be obtained from adaptation of standard container types currently available in the market;
The Discharge Valve (DV) used in the system to empty the Grey Water Storage Tank (GWST), may be obtained by adapting standard valve types currently available in the market;
■ The Water Source Selection Valve (WSSV) used in the system to guarantee that priority is given to grey water (when filling in the toilet flush tank) may be obtained by adapting valves currently available in the market, as for instance water float type valves used in toilet flush tanks.
The development of the MHTP component will however require specific design and manufacturing, but still no extraordinary difficulties are expected. Different turbine designs and pump designs shall be tested before the final product is defined. The design of the MHTP must assure that the following characteristics are incorporated:
■ The turbine side and the pump side casings of the MHTP need to be hermetically separated, so that no water leaks from the turbine casing to the pump casing in result of the difference in water pressure on both sides. This can be achieved, for instance, through proper design and use of a proper sealing;
«
■ The pressure drop caused in the incoming utility water flow when passing through the turbine side of the MHTP needs to be kept below a determined level, so that a minimum determined pressure is available in the shower and a satisfactory comfort in shower use can be attained. This can be achieved, for instance, with an efficient turbine-shaft-pump design (reducing hydrodynamic and friction losses) and through a proper case-by-case regulation of the By-Pass Valve (BPV); ■ Maximisation of the reliability and efficiency of the MHTP component at the lowest possible cost. This can be achieved, on one hand, through a proper choice of materials and, on the other hand, through the use of adapted components already massively available in the market, as for instance may be the case of small rotors developed for other types of applications;
■ The cleaning and replacement of the rotating part of the MHTP (turbine rotor, shaft and pump rotor) must be possible to be performed by the user of the system without needing any special tool or skill. This can be achieved through proper design of the casing.
The use of currently available components may also be possible in the development of the MHTP, as for instance may be the case of flexible impellers nowadays used in water pumps for car engine cooling, which may be tested as the rotor for the pump side of the MHTP. Nevertheless the optimised design and manufacturing of components for the final system may be necessary either to fulfil the final customer's requirements or to allow the product's cost effectiveness.