GAS Cylinder valve protection system

           VALVE PROTECTION SYSTEM

       General

Valve bodies are made of brass alloy and can get damaged, if it is hit against any object.  This may develop leak of LPG creating serious hazards. To prevent this, protection for the valve is provided by means of valve protection ring assembly on the top of the cylinder.

     Safety Cap

Valve outlet is fitted with safety cap manufactured out of Delrin Dupont 500 material to avoid damage to internals of the LPG valve and also to arrest the entry of dust particles and dirt inside the valve assembly. Safety cap  should  be put on to the valve at all times except for filling of the cylinder at the  plant and usage of the cylinder at the customer’s premises.  If the safety cap is not fitted on to the valve, valve may get damaged due to entry of dust particles or dirt into the valve and may cause leakage of LPG through the valve.  Hence, the safety cap is also considered as a protection for the leakage of the valve.  Safety cap can withstand  a  maximum working pressure of 2.45 M Pa of LPG and as such safety cap is very useful to stop the leakage from the valve, in case there is any leak through the valve seat. 

      ULTRAS0NIC VALVE CLEANING EQUIPMENT

   Each and every valve housing after machining are being cleaned by  the valve  manufacturers with Utrasonic Cleaning Euipment to remove any oil, grease, chips from the valve housing before assembly.  The solution used in Ultrasonic Cleaning Equipment is Trichloroethylene.  In this system, there are three chambers.  The first chamber contains liquid trichloroethylene which vibrates at ultrasonic frequency. The second chamber is of liquid trichloroethylene without any frequency and the third chamber is a vapour chamber.

 

9.7 DEGASSING OF CYLINDERS

                Work on LPG cylinders shall not be carried out in the enclosed space prior to degassing.

             Degassing should be carried out in CCOE approved site.  Cylinders shall  be degassed by purging the same by inert gas, steam or by filling water till it overflows.  The water shall be retained in the cylinders for not less than one hour to ensure that entire vapour or gas remaining in the cylinder comes out.  After emptying out the water, the cylinders shall be kept in inverted position and be tapped gently by non-metallic hammer to remove dust, rust or any loose remnants in the cylinders.

               

              After degassing, the inside of the cylinders shall be checked by an Explosimeter to ensure that the cylinders are gas-freed and shall again be taken up for de-gassing till it completely gas freed.

MARKING FOR AGE PROFILE

                  CCOE confirmed vide letter reference No. R:4(2)85/II dated 19.6.1991 agreeing to increase the periodicity of statutory testing of new LPG cylinders (first statutory testing) from 5 years to 7 years. 

                                  To facilitate segregation of the cylinders at the plant for statutory testing, a uniform procedure is evolved by the Oil Industry.  According to the procedure, color coding / marking is done on one of the vertical stay plates and inside face of the vertical stay of the valve protection ring.  Color coding of inside portion of the vertical stay plate for first statutory testing after 7 years from the  manufacturing date of the cylinder is as follows :

Background Colour	IS Spec.	Lettering	Yr. Of Mfr.	Yr. Of Testing	Coding  for qtr. Of manufacture
					Month of Mfr.	Code
Air Craft Blue	IS:108	White	1998	2005	JAN FEB MAR	A A A
Salmon Pink	IS:443	Black	1999	2006
					APR MAY JUN	B B B
Black	IS:521	White	2000	2007
Yellow	IS:355	Black	2001	2008	JUL AUG SEP	C C C
White	IS:127	Black	2002	2009
Sea Green	IS:217	Black	2003	2010	OCT NOV DEC	D D D
Dove Grey	IS:694	Black	2004	2011

Diagram No. 33 may be referred to for details of the marking on vertical stays.