Letter to Superintend Regarding Machinery Breakdown

To,

The Superintend,

ABC Shipping.

Sub: Breakdown of Provision Room Reefer Compressor

Dear Sir,

With respect to my telephonic conversation with you and subsequent emails with attached photographs you are well aware that our no.1 provision reefer compressor was completely broken down. At present no.2 compressor in is use and no.1 compressor overhauling is in progress.

As per your instruction we have carried out detailed investigation and the report is given below.

On 13/05/2014, it was observed that the compressor start/stop frequently, short cycling, and efficiency of compressor dropped considerably. Provision room temperatures were not maintained. On investigation a refrigerant leakage was detected. Further the leakage was rectified and decision was taken to recharge the system .

Refrigerant charging was carried out by 3/E (Third Engineer) and E/O (Electrical Officer) as both were experienced personnel. While charging the system, suddenly there was a heavy knocking sound and the compressor stopped. I was called up immediately and upon reaching in compressor room, I tried out to rotate the compressor shaft by hand. But it was found seized and there was  no movement.

At that time I was surprised to see that the charging hose was connected to the low pressure side of the compressor and liquid valve was kept open. Instead of charging with gas, refrigerant was going inside in liquid form.

Because of this liquid refrigerant entered directly into the compressor, it mixed with crankcase lube oil and liquid trapped at the top of the piston thereby creating heavy pressure. This huge pressure rise caused aluminum piston to smash into pieces. Connecting rod was also bend, bearings damages and piston seized inside the liner.

From the observation it was very clear that the accident took place because of wrong charging procedure, charging liquid refrigerant in low pressure side of compressor instead of gas.

My instructions to engineers was to charge with high pressure liquid refrigerant to HP side of the reefer system, i.e. before filter/drier. Again it was told to open liquid valve on the charging bottle partially only. Regarding this an internal circular was issued a month back and the same was signed by all engineers onboard.

Presently repair is in progress, we have already dismantled the compressor, found all pistons damaged and connecting rod bent, liner is also damaged. Luckily crankshaft is in good condition and can be used. We have one set of liner, piston, bearings and connecting rod as spares. We are planning to use them as replacement. I would like to request you to issue a circular regarding the incident in our fleet so that same incidents can be prevented.

New set of standing instruction already issued regarding charging procedure. LP side charging connection permanently sealed so that no one will use it again. Also refrigerant charging to be supervised by either chief engineer or second engineer.

I am attaching herewith a requisition for one set of piston, connecting rod, liner and bearings so that the spares can be maintained onboard. A trial run will be carried out as soon as the repairs are done, and you will be informed regarding the same.

At present no.2 provision reefer compressor is running satisfactorily, maintaining normal temperatures in provision rooms. No provision is damaged because of the incident and the running compressor is monitored periodically.

 

Thanking you,

Your Faithfully,

XYZ,

Second Engineer.