A kind of novel water shortage determination method for no flow sensor constant pressure water supply system
The present invention relates to water system fields, and in particular to a kind of novel for no flow sensor constant pressure water supply system
Water shortage determination method.
Background of related of the invention is illustrated below, but these explanations might not constitute it is of the invention existing
In constant pressure water supply system, other than most basic constant pressure, also there are many protections, wherein not having water in water inlet
In the case of, water pump is possible to run always to generate heat to damage motor.There are two the common methods of excessive low water level protection, connects flow biography
Sensor either uses power (electric current) to judge.
Judged with flow sensor, advantage is accurate and high reliablity, the disadvantage is that at high cost；Its principle is to utilize one
Flow sensor (perhaps water flow switch) when the analogue value fed back be lower than a threshold value after (or flow switch feedback it is low
After voltage) it can be determined that and pass through for no water flow, and then excessive low water level protection is shut down；Cheap flow sensor is slow in water inlet water flow
When slow, it is also possible to be mistaken for water shortage.
Judged with power, advantage is to reduce cost without adding flow sensor, the disadvantage is that versatility is low, is easy to miss
Sentence；Its principle is, in maximum frequency operation water inlet have the case where water can than no water in the case where power it is big；Work as function
Rate is may determine that when being lower than a threshold value as water shortage, but some water pumps, when water shortage, power can't decline, and compare instead
Electric current is also big when normal water supply, so these situations will be mistaken for water shortage；Some pumps power when water outlet is closed
Maximum, some pumps power in the case where water outlet standard-sized sheet is maximum, and the method versatility judged with power is too poor.
Summary of the invention
It is an object of the invention to propose a kind of novel water shortage judgement side for no flow sensor constant pressure water supply system
Method；Without flow sensor, cost is reduced；To water pump type also no requirement (NR), will not because of water pump type it is different and judge by accident, mention
The accuracy rate and versatility that water shortage determines in high constant pressure water supply system.
The novel water shortage determination method for no flow sensor constant pressure water supply system of one kind according to the present invention, using pressure
The value of feedback of force snesor is judged；Prove that the water inlet of water pump has water when constant pressure is effective, without doing water shortage judgement；And work as
When the water inlet water shortage of water pump, the pressure of pressure sensor feedback is unable to reach setting pressure, and water pump will operate in always most
Big frequency does water shortage judgement in maximum frequency, and steps are as follows；
Water pump runs the T0 time with maximum frequency, while filtering record hydraulic pressure P0, then with the speed frequency reducing of 1hz per second,
Reduce the frequency of F0；Water pump operation is stablized a seconds；Filter more new record hydraulic pressure P1 always in the process；If hydraulic pressure P0-P1 > △
P_d, then it represents that hydraulic pressure decline is obvious, and water outlet has water, is just restored to maximum frequency fortune at this time with the speed raising frequency of 1hz per second
Row；If hydraulic pressure P0-P1 < △ P_d, hydraulic pressure P2 at this time after water pump operation is stablized a seconds is recorded, then water pump continues with per second
The speed of 1hz is restored to maximum frequency, and then raising frequency 4hz, water pump operation are stablized b seconds again；During raising frequency, filter always
More new record hydraulic pressure P3；If hydraulic pressure P3-P2 > △ P_d, then it represents that hydraulic pressure has rising, is that user closes valve, needs to shut down, and
It is not that water shortage is shut down；If hydraulic pressure P3-P2 < △ P_d, can determine whether as water shortage.
Preferably, water shortage number cumulative number is added one if being judged as water shortage, if water shortage cumulative number is greater than setting
Water shortage judges times N, then may determine that as water shortage shutdown.
Preferably, described a seconds and b second is all between 0.5 second to 4 seconds.
Preferably, the △ P_d is that frequency reducing disturbs drop, between 0.05-0.15bar.
Preferably, the T0 time is between 0.5 minute to 3 minutes.
Preferably, described judge times N between 2 times to 5 times.
Preferably, described a seconds and b second is all 2 seconds.
In the case where pump water inlet water shortage, due to there is check-valves, water pump frequency reducing operation not will lead to the present invention substantially
The decline of water outlet pressure；And in the presence of water, water pump frequency reducing will lead to pressure and be decreased obviously；But valve is closed in user
In the case where, water pump frequency reducing will not be such that hydraulic pressure reduces, so needing raising frequency to handle, if raising frequency pressure energy rises, then it represents that close
Otherwise valve is exactly water shortage.
Compared with prior art, the invention has the beneficial effects that: 1) be not necessarily to flow sensor, reduce cost；2) to water
Pump type no requirement (NR), will not because of pump type it is different and judge by accident；3) improve water shortage in constant pressure water supply system determine it is accurate
Rate and versatility.
Exemplary embodiments of the present invention are described in detail below；Description to illustrative embodiments is only
It for illustration purposes, is definitely not to the present invention and its application or the limitation of usage.
In present embodiment, water shortage judgement is carried out using the value of feedback of pressure sensor；When constant pressure is effective, illustrate into
There is water at the mouth of a river, without doing water shortage judgement；When water inlet water shortage, setting pressure is not achieved in feedback pressure, to transport always
Row is in maximum frequency, so needing to do water shortage judgement in maximum frequency operation.
In present embodiment, deterministic process are as follows: the T0 time is first run with maximum frequency, while filtering record hydraulic pressure P0, so
Afterwards with the speed frequency reducing of 1hz per second, the frequency of F0 is at most reduced, then water pump is stablized 2 seconds again, filters always in the process more
New record hydraulic pressure P1, once hydraulic pressure (P0-P1) > Δ P_d, then it represents that hydraulic pressure decline is obvious, and water outlet has water, at this time just with every
The speed raising frequency of second 1hz is restored to maximum frequency operation；If after water pump is stablized 2 seconds and recording hydraulic pressure P2 at this time, hydraulic pressure
(P0-P1) < Δ P_d then judges possible water shortage, is restored to maximum frequency at this time and with the speed of 1hz per second, then again
Raising frequency 4hz water pump stable operation 2 seconds, within the period of this raising frequency, filters always more new record hydraulic pressure P3, once (P3-P2) >
Δ P_d, then it represents that hydraulic pressure has rising, is that user closes valve, needs to shut down, but is not that water shortage is shut down；If P3-P2 is small
In Δ P_d, then it represents that be really water shortage, water shortage cumulative number is added one at this time, sentence once water shortage cumulative number is greater than setting water shortage
Disconnected times N then may determine that as water shortage shutdown.
In present embodiment, is judged using water shortage cumulative number, repeatedly determine water shortage, prevent to cause due to sensor error
Erroneous judgement water shortage.
In present embodiment, in the case where water inlet water shortage, i.e., closing water inlet or water inlet are passed through air, water pump
It can be run with maximum frequency 50hz, set and determined within 1 minute once in system, determine that times N is set as 3；And 3 in the case where water shortage
Minute can be with orderly closedown, and indicator light shows water shortage failure；N is set as 2 can shut down and indicate failure for 2 minutes.
Although referring to illustrative embodiments, invention has been described, but it is to be understood that the present invention does not limit to
The specific embodiment that Yu Wenzhong is described in detail and shows, without departing from claims limited range, this
Field technical staff can make various changes to the illustrative embodiments.