Device for supplying liquid at constant amount and method for controlling same

A device for supplying liquid at a constant amount, comprising a constant amount chamber (1), an input pump (2), an output pump (3), a liquid level detection device (4), and a controller (5), wherein the constant amount chamber is provided with a liquid inlet (11) and a liquid outlet (12);

• the input pump (2) is provided with an input pump liquid feeding pipe (21) and an input pump liquid discharging pipe (22);
• the output pump (3) is provided with an output pump liquid feeding pipe (31) and an output pump liquid discharging pipe (32);
• the liquid inlet (11) is in matched connection with the input pump liquid discharging pipe (22);
• the liquid outlet (12) is in matched connection with the output pump liquid feeding pipe (31);
• the liquid level detection device (4) is provided with a high liquid level detection probe (41) and a low liquid level detection probe (42);
• the high liquid level detection probe (41) and the low liquid level detection probe (42) are provided inside the constant amount chamber (1);
• the high liquid level detection probe (42) is provided at a height higher than that of the low liquid level detection probe (41);
• the high liquid level detection probe (42) is used for detecting a high liquid level in the constant amount chamber (1), and the low liquid level detection probe (41) is used for detecting a low liquid level in the constant amount chamber (1);
• the input pump (2), the output pump (3), and the liquid level detection device (4) are each in matched connection with the controller (5), wherein the input pump (2) and the output pump (3) are diaphragm pumps.