Yuanyin Cola Machine – Standard Operating Procedure for Gas Cylinder Replacement
This operating procedure applies only to the replacement of food-grade carbon dioxide cylinders used with Yuanyin brand series cola machines. Gas cylinders are high-pressure special equipment. Operators must read through the entire procedure in advance and strictly follow the steps. Non-compliant operations may lead to equipment damage, personal injury, and other safety risks.
I. Core 4-Step Closed-Loop Operation (Must be performed in sequence; reversing steps is strictly prohibited)
Step 1: Pre-operation Preparation
Tool and Material Preparation: Prepare the dedicated cylinder wrench matching the cola machine cylinder connection, a qualified, full new food-grade CO2 cylinder, soapy foam for leak testing, and a clean cloth.
Gas Source Shut-off Operation: Locate the main valve of the old cylinder to be replaced. Turn it clockwise completely to close, thoroughly cutting off the gas source and stopping gas supply.
Step 2: Old Cylinder Removal and Component Inspection
Loosen and Remove the Connection: Fully seat the dedicated wrench onto the old cylinder connection thread. Confirm it is securely seated without deviation or slipping. Then smoothly turn counterclockwise to loosen the connection, separating the old cylinder from the high-pressure gauge.
Core Component Storage and Inspection: Remove the high-pressure gauge and carefully store the sealing gasket that comes with it. Confirm that the gasket is not deformed, damaged, or aged.
Connection Compliance Inspection: Inspect the cylinder connection and the high-pressure gauge connection threads one by one. Ensure the threads are not stripped, worn, contaminated with debris, damaged, or deformed. Components that do not meet the requirements must not be reused.
Step 3: Proper Installation of the New Cylinder
Pre-installation Confirmation: Verify that the new cylinder is a food-grade CO2 cylinder within its qualified service life, and that the valve threads are intact, not damaged or deformed. Correctly place the intact sealing gasket into the sealing groove of the high-pressure gauge connection, ensuring the gasket sits flat and flush, without misalignment or deviation.
Pre-tightening and Positioning: Precisely align the high-pressure gauge connection with the new cylinder valve threads. First, smoothly turn the threads clockwise by hand until it can no longer be turned by hand. Ensure the threads are not crossed or stripped during this process. Do not force it.
Proper Tightening: Fully seat the dedicated wrench onto the connection threads. After confirming it is securely seated without deviation, apply steady force to tighten clockwise to a reliable sealed state. Do not overtighten, as this may strip the threads or crush/damage the gasket, affecting the seal.
Step 4: Mandatory Leak Test (Absolutely cannot be omitted; must be performed in full)
System Pressurization and Stabilization: Slowly open the new cylinder main valve counterclockwise more than 3 full turns (can be fully opened) to allow gas to enter the lines smoothly. Observe the high-pressure gauge pointer. After it reaches the normal working pressure of the cola machine (standard range 70-80 psi), let it sit for 1-2 minutes to allow the system pressure to fully stabilize.
Leak Test Preparation: Mix soap and clean water in a 1:1 ratio to create a fine soapy foam. Place it in a spray bottle or container. Also prepare a clean cloth.
Full-Point Leak Test Operation: Spray the soapy foam evenly onto all sealing points (key inspection areas: the connection between the cylinder valve and the high-pressure gauge connection, the high-pressure gauge body seal, and all air line connections). Alternatively, dip the cloth in the foam and apply it evenly to the above points. Ensure every sealing surface is completely covered with foam; no point is missed.
Leak Judgment Criteria: After application, wait 30 seconds to 1 minute and observe the test points: ① If no bubbles appear and the foam does not expand, the seal is normal with no leak. ② If bubbles appear, the foam expands continuously, or bubbles emerge continuously, there is a leak at that point. Immediately mark the leak location.
Leak Exception Handling: If a leak is found, immediately close the new cylinder main valve completely by turning it clockwise. Then remove the high-pressure gauge, check if the sealing gasket is damaged or misaligned, and if the connection threads have debris or are crossed. Replace with a qualified gasket, clean the threads, realign and reinstall, tighten, and then repeat the full leak test procedure above until there is no leak. If leaks persist after multiple reinstallations, stop immediately and check whether the high-pressure gauge or the cylinder connection is damaged. Replace with qualified components promptly. Do not use the equipment with a known fault.
Test Acceptance Criteria: No leaks at any sealing point, and the high-pressure gauge pointer remains stable (no significant drop within 5 minutes). Only then is the cylinder replacement considered qualified, and the cola machine can be started for normal use.
II. Inviolable Safety Red Lines (Must be followed throughout; violators will face significant safety risks)
Never disassemble or install a cylinder while it is under pressure. Before operation, confirm that the cylinder main valve is completely closed. Do not use non-matching tools. Do not apply force without fully seating the wrench onto the threads to prevent slipping causing injury or component damage.
The sealing gasket is a core sealing component. Do not lose it, and do not reuse it if it is damaged or aged. Do not perform cylinder installation without a qualified matching gasket.
After each cylinder replacement, a full leak test procedure must be completed. Do not put the equipment into use if the leak test has not been performed or has failed.
Do not use non-food-grade CO2 cylinders, cylinders that have expired for inspection, or cylinders that are damaged or deformed. Do not modify the cylinder connection or related accessories without authorization.