Hot gas defrosting system

[tjk2007]

Dear all,

Hereby i have enclosed P&I drawing for a R-22 Tube Ice machine.The details for Hot gas defrosting from manufacturer side is as follows;

After freezing, the discharge hot gas from the compressor will be injected inside the ice drum instead of the condenser for harvesting the tube ice.

My doubt regarding hot gas defrost is;





After freezing completes the liquid line solenoid valve will cut off the liquid. No expansion takes place in the ice machine since there is no liquid supply.
Then from where the compressor is sucking the gas for compression and discharge.
If my doubt is wrong pls explain the process during hot gas defrosting.

Regards,

TJK

[sterl]

A sequence of valve dispositions would help, but unless I'm missing something, this thing is going to cool the condensing water during the harvest, and that generates the suction vapor for the machine....The condensing pressure control being based on refrigerant discharge and bypass. In effect, the cycle is reversing once all the checks and regulator have responded to the changes in pressures as the thing transitions.

[tjk2007]

A sequence of valve dispositions would help, but unless I'm missing something, this thing is going to cool the condensing water during the harvest, and that generates the suction vapor for the machine....The condensing pressure control being based on refrigerant discharge and bypass. In effect, the cycle is reversing once all the checks and regulator have responded to the changes in pressures as the thing transitions.

i think the condenser water supply will be closed during harvest time.

[Sandro Baptista]

Hi,

See my comments below with blue



Dear all,

Hereby i have enclosed P&I drawing for a R-22 Tube Ice machine.The details for Hot gas defrosting from manufacturer side is as follows;

After freezing, the discharge hot gas from the compressor will be injected inside the ice drum instead of the condenser for harvesting the tube ice.

My doubt regarding hot gas defrost is;






After freezing completes the liquid line solenoid valve will cut off the liquid. No expansion takes place in the ice machine since there is no liquid supply.
Then from where the compressor is sucking the gas for compression and discharge.
It will sucks from the water condenser, wich will work as water chiller. See the diagram...with pink marks arrows when the defrosting is running (the bypass solenoid valve opens and I think that after a few minuts or seconds the Harvest cycle suction valve will open). When the corresponding pressure is well above the saturation temperature of 0ºC (see the end defrost pressostat) it means that the ice already has fallen to the ice storage silo.

I hope my analisys has been useful.

Best Regards




If my doubt is wrong pls explain the process during hot gas defrosting.

Regards,

TJK

[josei]

Dear all,

Hereby i have enclosed P&I drawing for a R-22 Tube Ice machine.The details for Hot gas defrosting from manufacturer side is as follows;





Your Comments about LZ-5000 TIM and my Notes

1-After freezing, the discharge hot gas from the compressor will be injected inside the ice drum instead of the condenser for harvesting the ice.

NOTE. The hot gas discharge is directed both to ice drum (Thaw Chamber and body) and to condenser.


My doubt regarding hot gas defrost is;

2-After freezing completes the liquid line solenoid valve will cut off the liquid.

NOTE.Not necessarily, it has a TES20 thermo-pressure valve closing liquid line according to condition of succion line leaving ice drum.

3-No expansion takes place in the ice machine since there is no liquid supply.

NOTE.Although that were true, there is liquid inside the ice drum that is partially flooded with refrigerant.

4-Then from where the compressor is sucking the gas for compression and discharge.

NOTE.There is gas leaving from ice drum during Harvest Cycle and from Suction Accumulator.

The harvest cicle time is very short compared with freezing cicle, (about 1/15)

[tjk2007]

Thank you for all your suggestions

TJK