HOW TO CHOOSE A REGULATOR
Single Stage vs. Dual Stage
Single stage regulators reduce pressure in a single step to deliver pressure within a specific range. Regulators designed this way will show a slight variation in delivery pressure as the cylinder pressure falls during use. For this reason, single stage regulators are best suited for applications where constant outlet pressure is not critical, an operator can monitor and readjust pressure, or where inlet pressure is constant. Dual stage regulators perform the same function as single stage regulators. However, delivery pressure remains constant as the cylinder pressure decreases, and greater accuracy in pressure control is maintained because inlet pressure is reduced in two steps. CONCOA recommends dual-stage regulators for critical applications requiring a consistent and precise outlet pressure, such as laboratory experiments, industrial processes, and medical applications.
Helium Leak Integrity
Helium leak integrity is a measurement of how well a regulator prevents gases from leaking into or out of a regulator body. The measured quantity is expressed as a flow rate such as 1 x 10-9 cc/sec He (1 billionth of a cc/sec). In this case, a Helium Leak integrity rating of 1 x 10-9 would indicate that the regulator would leak enough gas to fill one cubic centimeter every 33 years. If the rating were 1 x 10-3, the regulator would leak enough gas to fill one cubic centimeter in just 17 minutes. Helium is used as the test gas because it is chemically inert, is easy to detect, and is an extremely small molecule able to pass through the smallest leak. The lower the helium leak specification, the better the regulator will be at preventing leaks into the atmosphere and minimizing contamination from gases outside the body.
Materials of Construction
The regulator's component materials should be selected based on the properties and purity of the gas being used. CONCOA manufactures regulators from brass and 316L Stainless steel. Brass is economical and compatible with most non-reactive gases, making it suitable for standard applications. For applications involving corrosive gases, high purity requirements, high pressures, or extreme temperatures, 316L stainless steel is preferable. It is the go-to material in pharmaceuticals, biotechnology, food and beverage, and analytical laboratories. In applications where 316L stainless steel is not sufficiently inert or corrosive resistant, CONCOA regulators treated with SilcoNert™ 2000, such as the 420/430 Series, ensure unsurpassed analytical accuracy. The CONCOA 455 Series electroless nickel-plated regulators are designed for applications involving sulfide and chloride compounds. Passivation for fluorinated compounds is also available. Finally, there is an option to choose between forged body construction and barstock construction. Forged body regulators are economical; however, their internal surface finishes are relatively rough compared to barstock body regulators. Barstock body regulators have all whetted surfaces machined to a smooth finish, which reduces the possibility of contamination.
Cylinder Connections
CONCOA manufactures cylinder connections that conform to worldwide standards. In the US, the Compressed Gas Association (CGA) has designated specific cylinder connections for each gas service and pressure rating. There are approximately a dozen commonly used CGA fittings, with others used for specialty purposes. Identifying the correct CGA fitting for a specific gas ensures safe and proper connections. A CGA Fitting Reference Chart of standard inlet connections along with corresponding gas types and other information is available on the
CONCOA website. Figure 1, CGA-580 Inlet Connection is an example of the information presented on that chart. CONCOA also offers cylinder connections that conform to international standards, including DIN 477, BS 341, JIS (Japan), and KS (Korea). It is important to note that a CGA fitting limits the temperature range of a regulator to the specifications of that fitting.
Flow Charts
Flow charts provided with every CONCOA regulator offer a graphical representation of test results that show the change in outlet pressure. To use the chart, determine the maximum no-flow pressure permitted by the system. Locate this pressure on the vertical axis of the chart. If there is no curve for your specific condition, interpolate a curve. Follow the curve to the desired flow rate on the horizontal scale. Read horizontally to the left to determine the corresponding pressure drop. Because flow rate is dependent upon inlet pressure, data is presented at full cylinder pressure (2000 PSIG), partially full (500 PSIG), and nearly empty (200 PSIG).
Diaphragms
The diaphragm is a pressure sensing control element crucial to the function of the regulator and the purity of gas delivery. Stainless steel diaphragms are strong and corrosion resistant. The metal-to-metal seal prevents gas contamination and has low leakage rate characteristics. Neoprene diaphragms may offer more sensitive pressure control, but do not offer the gas purity of stainless steel.
Specialty Applications
While a single or dual stage regulator of the appropriate material will suffice in most gas services, some applications require specially designed regulators. CONCOA addresses these specialty needs with a range of innovative solutions. For example, within the 400 Series, the 492/493 Series single stage regulators safely deliver gas at extremely high pressures with low static pressure and high leak integrity. Similarly, the 483/484 Series pipeline and 485/486 Series manifold regulators ensure high flow in high purity gas applications, with a balanced stem seat design for steady outlet pressure.
In the 300 Series, the 305 and 315 Series regulators, featuring a standard 2-15 LPM flowgauge calibrated for carbon dioxide or a custom 2-15 LPM flowgauge, are designed for medical laboratory applications, such as blood gas analysis. CONCOA's 308 Series electrically heated regulators alleviate flow reduction by eliminating freeze-up associated with high flows of carbon dioxide or nitrous oxide in critical laboratory settings. Compact and efficient, the 325 Series regulators provide pressure regulation for non-corrosive gases in lecture bottles, making them suitable for educational, laboratory, and research applications.
Finally, the CONCOA 203 and 213 Series cylinder regulators deliver high purity, non-corrosive, or liquefied gases in applications requiring delivery pressures as low as 0.1 PSIG (7 mBAR). CONCOA’s commitment to addressing specialty needs means that every regulator is not only meticulously designed but also customizable to meet specific requirements.
Understanding Capsule® Technology
To meet the rigorous requirements of end-users in the analytical, scientific, and electronics markets, CONCOA has developed a unique regulator seat assembly that incorporates the numerous individual parts of a standard regulator seat into a single component. This design allows the Capsule to be tested as a separate component before assembly into the regulator. Completed CONCOA regulators are then 100% tested giving the seat, or “heart” of the device, a double test. The result is a longer life and reliable performance.
1. Lateral Flow Passages – Instead of impinging directly on the diaphragm, the gas enters the low pressure chamber through a side orifice of the Capsule®. This smooth transition from high pressure to low pressure reduces the effects of gas surge on the diaphragm and minimizes regulator hum. In addition, the lateral flow passages induce a swirling effect which yields a completely swept internal cavity for complete purging.
2. Multiple Orifice Sizes–Each regulator has a specially designed Capsule® to optimize regulator characteristics over a broad range of applications. However, some applications require higher or lower flows than the standard Capsule® can offer. By substituting a Capsule® with a larger or smaller orifice, CONCOA can tailor the regulator to meet a specific requirement.
3. PTFE Seat–The standard seat material is high density PTFE. PTFE is an inert material that will not react with or contaminate any high purity gas. In addition, PTFE retains its sealing properties over a wider temperature range than other seat materials. The inlet pressure rating of all CONCOA regulators with a PTFE seat is 3000 PSIG (210 BAR). With the optional PCTFE-seated Capsule®, the pressure rating increases to 4500 PSIG (310 BAR).
4. High-Load Marginal Spring – The purpose of the marginal spring is to close the seat independently of gas pressures. The innovative CONCOA Capsule® technology utilizes a high-force spring that assures a gas-tight seal under all conditions.
5. 10-Micron Filter – Particles trapped between the seat and orifice prevent proper seat closure, causing the regulator to fail. The Capsule® incorporates a 10-micron filter that surrounds the seat components and prevents the entrance of these damaging particles, virtually eliminating the cause of such seat failures. This filter is fine, and its large surface area is resistant to clogging, allowing unrestricted flow. The 10-micron filter is a factor in the long life and reliable performance of all CONCOA regulators. The stainless steel 10-micron mesh Capsule® is patented CONCOA technology.
Conclusion
Understanding the design and operation of CONCOA regulators ensures selecting the safest and most efficient solution based on application needs. For tailored regulator solutions and expert assistance, contact CONCOA with specific pressure and flow requirements, sizing information, temperature ranges, and other essential information.