CAC – Constant Pressure Cylinders

CAC - Bình khí có áp xuất không đổi

Constant Pressure Cylinders designed with an internal piston and seals, the CP2 cylinder is pressured with an inert gas supply, and then turned around and filled slowly from the opposite end.


By letting the gas push against the piston, slowly venting the pre-charge gas, the sample is taken at full line pressure from start to finish. While the cylinder is being emptied, full pressure is being maintained and the gas composition is not being altered as a result of pressure reduction. The cylinder is equipped with valves, safety reliefs, and gauges on both ends and thus the pressure can be controlled and monitored at all times on both ends.

At Welker, quality and craftsmanship in both construction and design are most important. All of their constant pressure cylinders are designed with a standard 4-to-1 safety factor, unequaled in the industry. Constructed of 316 SS and honed to 2-4rms, Welker® CP2 cylinders give years of dependable service and quality results.



This cylinder utilizes a pin tracker to provide positive reference to the location of the piston. The tracking system is highly resistant to heat and chemical attack, and may even be used at moderate oven temperatures. Convenient size and ease of use make this cylinder ideal for the collection and transport of natural gases. A must for high BTU content!

CAC-CP-2SY (Syringe Style)

Quick, easy-to-read capacity reference and ease of use typify this constant pressure sample cylinder. An indicating rod and an 80% of capacity indicating tower provide positive reference to the location of the piston. T-handle can be easily attached to indicator rod for syringe-style use.


This cylinder offers both convenient size, with its short overall length, and a gravity action mixer. The stainless steel mixer works in conjunction with the cylinder saver rod; mixing is accomplished by inverting the cylinder several times. The mixer slides along the cylinder saver rod, eliminating any contact with the cylinder wall. The piston is tracked by a pin tracker. Great cylinder for transporting light liquid hydrocarbons when stratification and/or space are concerns. Used extensively by specialty gas companies for chromatograph standard mixes.


Ease of use and superior mixing action make this the most respected mixing cylinder available. The CP-2M features an indicating rod with an 80% of capacity indicating tower for quick and positive reference to the collected volume and a mixer with vortex action for complete mixing of stratified product.

Data sheet

Installation, Operation & Maintenance Manual

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