A new water shortage judgment method for constant pressure water supply system without flow sensor

Abstract

The invention discloses a novel water shortage determining method for a no-flow sensor constant pressure water supply system. In the case that a water inlet pipe of a water pump is short in water, thewater pump operates by reducing the frequency and does cause reducing of the pressure of a water outlet due to the fact that a check valve is arranged; in the case that the water inlet pipe has water, frequency reduction of the water pump leads to significant reducing of the pressure; but in the case that a user closes a valve, frequency reduction of the water pump does not lead to reducing of the water pressure, so that frequency increasing processing is required, if the increasing frequency pressure can increase, it means that the valve is closed, otherwise water shortage occurs.

Description

technical field [0001] The invention relates to the field of water supply systems, in particular to a novel water shortage judging method for a constant pressure water supply system without a flow sensor. Background technique [0002] The technical background related to the present invention will be described below, but these descriptions do not necessarily constitute the prior art of the present invention. [0003] In the constant pressure water supply system, in addition to the most basic constant pressure, there are many kinds of protection. In the case of no water in the water inlet, the water pump may run all the time, causing heat to damage the motor. There are two commonly used methods for water shortage protection, connecting the flow sensor or judging by power (current). [0004] Judging by the flow sensor, the advantages are high accuracy and reliability, and the disadvantage is high cost; its principle is to use a flow sensor (or water flow switch), when the feed...

AI Technical Summary

Problems solved by technology

[0004] Judging by the flow sensor, the advantages are high accuracy and reliability, and the disadvantage is high cost; its principle is to use a flow sensor (or water flow switch), when the feedback analog value is lower than a threshold value (or the flow switch feedback low voltage After) it can be judged that there is no water flow through, and then the water shortage protection shutdown; the cheap flow sensor may also be misjudged as water shortage when the water flow at the water inlet is slow

[0005] Judging by power, the advantage is that there is no need to add a flow sensor, which can reduce costs, but the disadvantage is that it has low versatility and is easy to misjudge; its principle is that when the water inlet is running at the maximum frequency, the power will be higher when there is water in the water inlet than when there is no water. Large; when the power is lower than a threshold, it can be judged as water shortage, but when some water pumps are short of water, the power will not drop, but the current is larger than the normal water supply, so these situations will be misjudged as water shortage ; Some pumps have the highest power when the water outlet is closed, and some pumps have the highest power when the water outlet is fully open. The method of judging by power is not universal