Frequency Conversion Constant Pressure Water Supply Device

Introduction of Frequency Conversion Constant Pressure Water Supply Device

The frequency conversion constant pressure water supply device is easy to operate and can replace the ship's fresh water or sanitary water tank to provide domestic water with stable pressure or cleaning water for the ship.

Working Principle

The pressure sensor samples the water pressure of the pipes, converts the pressure signal into an electrical signal, and transmits it to the PID regulator.

Then compare and calculate with the pressure value set by the user, and convert the calculation result into a frequency signal and a pump number signal and send them to the inverter and the programmable controller (PLC) respectively. The inverter adjusts the speed of the pump motor as needed.

The programmable controller controls the withdrawal or input of the water pump, so as to achieve the purpose of adjusting the water consumption and ensuring a constant pressure.

Drawing of Frequency Conversion Constant Pressure Water Supply Device

Parts list

No.	Name	Material
1	Pump	Stainless steel
2	Stop valve	Cast Iron
3	Check valve	Stainless steel
4	Vacuum gauge	Assembly
5	Control box	Assembly
6	Pressure gauge	Assembly
7	Pressure switch	Assembly
8	Needle valve	Stainless steel
9	Ball valve	Stainless steel
10	Water level switch	Assembly
11	Buffer pressure tank	Assembly
12	Pressure transmitter	Assembly

Functional Features

①．Comprehensive alarm extension function

In the working state, there is a normally closed/normally open (passive) contact interface when the system fails, which can realize remote alarm.

②．Water shortage protection function

The system has its own float level switch. When the water supply pipeline is short of water, the system will automatically stop and issue an alarm.

③．Automatic frequency conversion function

Under the double-pump variable frequency working condition, it has the function of automatic frequency conversion and constant pressure. When the water consumption is large, the pump can be automatically converted to the frequency conversion and added to the pump. When the water consumption is reduced, the pump can be automatically reduced. When no water is used, the system will automatically sleep. When the value is set, the system will automatically wake up to work.

④．Automatic power frequency function

There is a pressure water tank function under the double-pump frequency conversion condition, and the double-pumps work alternately at this time.

⑤．Single pump frequency conversion function

When a water pump is repaired, it can choose the single pump condition, and then choose the 1# or 2# pump to work at the power frequency.

Maintenance Guide

Maintenance must be performed 5 minutes after the system is powered off

Daily maintenance

1.The air pressure of the new equipment is checked every 3 days in the first month. If the air pressure is stable and does not drop, it will be checked every month thereafter. Check the air pressure money first stop the pump, then vent the system pressure to 0, and then check the air pressure in the pressure tank (0.12-0.14MPa) with the barometer in the spare parts / tools.

2.Clean up the surface dust monthly.

3.Perform a system power-off reset once a month, the power-off time is not less than 5 minutes, and then start the system normally.

Preventive maintenance

If the following abnormalities are found in daily use,must stop the machine and repair.

1.The water pump fan is blocked by foreign objects, it should be cleaned in time.

2.The bearing of the water pump motor has a screeching sound of friction, more than 80db.

3.The water pump and motor go hot, more than 55°C, need to check the cause.

Troubleshooting and Solution

No.	Fault description	Possible reasons	Troubleshooting and solution
1	Under the condition of frequency conversion, the system will not sleep when no water is used for a long time, and the frequency of the double pump of the system is 50HZ.	1.Pipeline leakage 2.Check valve damage 3.Air pressure tank burst 4.Transmitter wire is broken or faulty	1.Check piping, drain leaks and faults 2.Change to single pump work and stop using water. If the pump does not stop or starts soon after it stops, it means that the check valve is leaking, and the check valve should be replaced. 3.After the system hibernates and shuts down, it starts again soon, indicating that the airbag has ruptured 4.Check the transmitter connection and reconnect or replace it
2	Under the frequency conversion condition, when the water is used for a long time, the system works at a single frequency, the frequency is 20HZ, and the water pressure is lower than 0.2MPa.	1. The transmitter cable is short-circuited. 2. Transmitter is damaged.	1.Check the transmitter connection and reconnect it. 2.Replace the transmitter.
3	Under the condition of power frequency, the water pump does not stop and the water pressure is higher than 0.35MPa	1.The pressure switch is damaged.	1.Replace the pressure switch.
4	Under power frequency conditions, the unmanned water pump does not stop, and the water pressure is lower than 0.15MPa	1.Check valve is broken. 2.Water pump is broken.	1.Close the water inlet valve of the pump that is not started to see if the water pressure rises. If the water pressure rises and can be stopped, the check valve of the unstarted pump  is broken and needs to be replaced. If the water pressure cannot rise, the water pump is broken. The water pump needs to be repaired.

No.	Fault description	Possible reasons	Troubleshooting and solution
5	Under power frequency or frequency conversion conditions, the system does not start and alarms, and there is no fault code on the panel.	1、The float level switch is broken.	1. Remove the float level switch. In the on and off state, use a multimeter to measure the on-off of the two wires of the float level switch. If any abnormality is found, it is broken and needs to be replaced.
6	Water leakage at the connection between the pump body and the motor (under the middle of the pump)	1.Mechanical seal burned out.	1.Replace the mechanical seal.
7	Under normal working conditions, the noise is relatively large	1.Bearings are worn out	1.Replace the bearing.
8	Inverter common fault codes	A2001 lack of phase A5001 not connect to control plate F0004 Short circuit F008 Transmitter failure F0009 Motor overheating F0012 Overload