| What causes noise to occur in a check valve? | Check valves may chatter due to a variety of reasons. An oversized check valve is often indicated by continuous valve chatter, which is the repeated opening and closing of the valve that occurs when the valve is only partially open. System design may also contribute to check valve noise. For instance, a quick coupling installed in series with a check valve may contribute to noise. Changing spring crack ratings or relocating the valves are common cures for reducing or eliminating chatter. |
| Can a check valve be used as a relief valve? | Yes, it is a common practice. However, the crack pressure settings are limited to the few options available. Relief valves are available for customers to use at any desired setting between 10 and 6000 psig. |
| Can check valves be mounted vertically or horizontally? | All our series check valves can be mounted both horizontally or vertically as they are spring activated with only one exception being the LC Series Lift Check Valve. This is because the design of the LC Series is gravity assisted in order to achieve the back seal. |
| What is the difference between C and CO check valves? | Essentially the CO Series is assembled & tested in a clean room and have leak rates tested at the factory during assembly. In simple terms the C Series is a standard product and the CO is for high purity / cleanliness and leak rate control. |
| Can C series valves be manufactured to meet MR0175 | Yes just add -NC after the material designation. |
| Is the PTFE used in the C series valves FDA approved and/or virgin PTFE? | The PTFE is virgin but not FDA approved |
| How does the LC check valve perform with respect to temperature and pressure? | The LC Series Lift Check Valve P-T curve is the same as the U-Series with the HT option up to 900°F. |
| Do C series check valves have a minimum pressure to seal? | The CB Series Check Valves follow the re-seal pressures in the catalogue. The 100psi min back pressure note does not apply. |
| Parker literature says that Hi Check crack at <10psi. What does that mean? | It means that Hi Check Series will crack at a pressure of less than 10psi. We can't state the exact pressure. Parker also offers another range of check valves, the CH series, that will crack at 1,3 or 5 PSI. |
| Are our check valves suitable for liquid nitrogen? | No, O-rings will not handle -196 degrees. |
| We are using Sodium Hypochlorite (bleach) and the Inconel (X750) spring has apparently dissolved. What's going on? | Bleach does not like most metallic materials. Inconel springs will only last 12-24 months in the this media. We recommend Ti springs. |
| Are titanium springs to NACE? | Yes, they can be. (Table A.1 in NACE MR0175 says no, but this is interpreted as a guideline and is not definitive. Table A.41 gives the environmental and material limits for use of ti and tantalum alloys.) |
| Can Hi Check be fire safe? | No. |
| Can we use check valves on steam? | No, we do not offer a steam service check valve, the LC Series Lift Check Valve is typically only used on liquids, and on steam vapor it will leak. |
| Does the parent material affect the cracking pressure? | No, the cracking pressure for a given part number is the same regardless of material. |
| Are check valves considered as zero leak? | This would be classed at a zero leak product according to ISO 5208 - Allowable leakage Rate A - No visually detectable leakage for the duration of the test. |
| What is the spring material, X750 or Stainless steel, for Hi Check? | The NACE versions use X750, the 'normal' version uses stainless steel (316) |
| Can we quote no lube on C Series Check Valves? |
We can offer this only with PTFE seats, and it will be assembled with PTFE tape. C-series are not available with o-ring seals. |
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