BE1016930A3 - Water sterilization device powered by solar energy, includes bypass circuit for sterilizing heat exchanger - Google Patents

Abstract

A bypass valve (13) is provided for diverting the liquid to a circuit (A) used to sterilize the heat exchanger (5) normally used to cool the sterilized liquid. A device for sterilizing a liquid uses solar energy to heat the liquid to a suitable sterilization temperature without it boiling, the latter being achieved by heating the liquid under pressure and placing an overpressure valve (9) at the liquid outlet. The liquid circulates around a conduit in the center of a double-walled glass tube which is heated by solar energy. Liquid is introduced via a pump (3) which is driven by an electric motor (11) regulated via a temperature sensor (7, 14) which switches the pump off when the temperature of the liquid falls below the sterilization temperature. The pump is powered by a solar panel (12). The sterilized liquid is delivered to a thermally insulated vessel (8) located in the liquid circuit and then cooled using a heat exchanger which is heated according to a counter-flow principle, the heat transferred being used to sterilize untreated liquid. A bypass valve (13) is provided which when opened diverts the! flow of water to the heat exchanger to a circuit (A) behind the latter which is used to heat the heat exchanger to a sterilization temperature without heat being transferred to the untreated liquid.

Description

Adjustment Improved solar water sterilizer 1 Description

It is a device for sterilizing liquids using solar energy.

This is done by heating the contaminated liquid above the sterilization temperature for a certain time. To prevent the liquid from boiling, the system will operate under pressure to prevent this boiling.

This device uses solar energy to heat the contaminated fluid to a suitable sterilization temperature. The invention uses double-walled glass tubes to collect the solar energy. The heat is directed and blasted to the center of the double-walled glass tube. The liquid circulates in a tube that is in the center of the glass tube. The liquid to be sterilized is allowed to flow through this tube at an appropriate speed, so that the liquid can reach the sterilization temperature.

By placing an overpressure valve at the outlet, an overpressure can be obtained in the liquid circuit, which will prevent the boiling of the liquid at that particular temperature and pressure. The introduction of the liquid is done via a pump. This pump is driven via an electric motor that is controlled by a temperature sensor that closes an electrical circuit when the sterilization temperature is reached. This sensor will switch the pump off again if the temperature falls below the sterilization temperature. The electric motor is driven by a photoelectric panel.

In order to obtain a sufficiently long sterilization time of the liquid, the heated liquid flows at sterilization temperature through a thermally insulated sterilization vessel which is located in the circuit after the thermally insulated glass solar collector tubes. After sterilization, the water is cooled in a countercurrent heat exchanger, which transfers the heat from the sterilized water to the contaminated water that still needs to be sterilized.

The adaptation and invention is an adaptation to the liquid circuit in the counterflow heat exchanger. Since in the circuit at the outlet of the heat exchanger the temperature of the liquid comes out of the overpressure valve below the sterilization temperature, there is a possibility of bacteria growing at that location in the circuit.

The invention will ensure that the entire heat exchanger can be brought to sterilization temperature so that the entire heat exchanger and the pressure relief valve can be sterilized.

With the insight to better demonstrate the features of the present invention, a preferred embodiment without limiting character is described below with reference to the accompanying drawing.

Figure 1: A schematic drawing of the sterilization cycle

This figure provides a schematic overview of the various elements of this invention for sterilizing contaminated water with solar energy. The water to be sterilized is located in the vessel (1) in which the water is decanted and pre-filtered. If this invention is used for sterilizing unsafe tap water, this tap water can be directly connected. The entire solar collector (6) containing the glass tubes must be placed in the sun. In the center of the vacuum-insulated glass tubes there are metal tubes through which the water to be sterilized flows. The solar collector is inclined to better face the sun. Because the hottest water rises upwards, the highest temperature in the collector at the top will be reached (6-up). At the start of the sterilization process, the pump does not yet work because the sensor switches (7) and (14) are open and no current can flow to the motor of the pump. A privileged setting for the sterilization temperature is, for example, that the sensor switch (7) closes at 140 ° C and opens again at 120 ° C and Sensor switch (14) closes at 100 ° C and opens at 80 ° C. By closing the sensor switches (7) and (14) the motor (11) of the pump (3) is powered because at that moment the sun is shining on the photoelectric solar panel (12) which then supplies the power to the motor (11) ). The motor (11) drives the pump (3), which draws the water from the tank (1) over a non-return valve (2) and pumps it into the circuit through the non-return valve (4). The entire water circuit is kept under pressure by a pressure relief valve (9) at the end of the flow circuit. A preferred pressure for this pressure relief valve is 4 kg / cm 2. However, it is also possible to operate the system with slightly lower pressures, for example 2 kg / cm 2 or much higher pressures. As soon as the pump motor (11) has been activated by closing the temperature sensor switches (7) and (14), the flow of the water starts and the already heated water is pushed into the sterilization vessel. The flow rate of the pump (3) and the dimensions of the sterilization vessel (8) are adjusted to each other in such a way that the water remains in the sterilization vessel for sufficient time. The sterilization vessel (8) is very well thermally insulated so that the water remains at 130 ° C for a sufficiently long time.

The hot sterilized water flows from the sterilization vessel (8) into the heat exchanger (5) where it releases its heat to the cold contaminated water that comes out of the pump (3). By using the heat exchanger (5) the cold water is already preheated very well so that it can reach the sterilization temperature faster in the solar collector (6). Through the pressure relief valve (9) the cooled sterile water is released from the circuit in a container (10) for the sterile water.

As soon as the sun is no longer powerful enough to bring the water in the collector (6) to the sterilization temperature, the temperature sensors (7) and (14) will interrupt the circuit so that the pump motor (11) stops. As a result, the water circuit in and after the sterilization vessel (8) always remains filled with sterile water. The improved solar water sterilizer will therefore automatically stop as soon as there is cloudiness or when evening falls without contaminated water coming into the container (10).

The stagnation temperature, which is the maximum temperature without flow of the water that can be achieved in the collector with the glass vacuum tubes (6), is more than 200 ° C. The pressure relief valve (9) ensures that the pressure cannot exceed, for example, 3 kg / cm 2. The pressure relief valve (9) therefore also serves as a safety valve against overpressure of the water at too high temperatures.

In order to prevent the growth of bacteria in the cold part of the sterile water in the heat exchanger, the valve (13) between non-return valve (4) and heat exchanger (5) will periodically interrupt the water circuit B to the heat exchanger (5). and open water circuit A.

Water circuit A will divert the contaminated water behind the heat exchanger. As a result, the heat in the heat exchanger can no longer be dissipated, so that the entire heat exchanger (5) reaches sterilization temperature.

The invention described here with adaptation of the cycle is mainly intended for sterilizing contaminated water, but can also be used for sterilizing other aqueous liquids.

Claims (1)

2 Conclusions See patent 2003/0211

The circuit B is interrupted via valve (13) and circuit A is opened. This prevents the heat exchanger from cooling down. So that the entire heat exchanger can be sterilized at regular intervals. The pressure relief valve could autonomously also act as a controller if the pump and / or temperature sensors were to be cut off.