Technical selection
Specifications and configuration
Reference — FITOK CL union-bonnet stainless check valve series
| Parameter | Documented value / configuration |
|---|---|
| Documented construction | All-stainless check valve with union bonnet; bonnet nut above body for specified horizontal installationConditions: scope: Manufacturer stated orientation; not interchangeable with freely oriented inline series |
| Manufacturer max working pressure | up to 414 barConditions: scope: Manufacturer series maximum, not combined with the full listed temperature span |
| Listed temperature span | -53 to 482 degCConditions: scope: Subject to pressure-temperature curve, exact seal and configuration |
| Documented tube end examples | CLSS-FL4, CLSS-FL6 and CLSS-FL8 use corresponding FITOK tube-fitting ends in the dimension tableConditions: scope: Examples with separate dimensions; pictured valve is not assigned a verified order code |
| Reverse to forward flow coefficient | Less than 0.1% of forward-flow coefficient, as stated for CL seriesConditions: scope: Manufacturer series statement, not a selected-valve leakage certificate or nominal cracking pressure; CL requires horizontal bonnet-up installation |
| Opening pressure basis not catalogued | Unlike the adjacent CV, CA, CH, CO and COA opening-pressure entries, the FITOK CL series feature/ordering section does not give a nominal cracking or set-pressure option. It explicitly requires horizontal installation with the bonnet nut on top. Specify required opening/reseal behavior for the selected line and confirm with the supplier; do not transfer another series' spring rating.Conditions: scope: Documented absence in this catalogue; not a measured CL cracking pressure |
Manufacturer series reference. Confirm the exact order code, mating parts and stated conditions for the quoted configuration.
Overview
This CL-style stainless check valve has a union-bonnet construction that changes installation and service access compared with compact inline check valves. It is a manufacturer reference for a buyer-defined liquid circuit, not a confirmed site supply item.
Construction and interfaces
The pictured body has a prominent top bonnet above two in-line ends. The manufacturer specifies an all-stainless construction and horizontal installation with the bonnet nut above; tube-fitting sizes are documented separately in its ordering table.
Selection
Reserve horizontal mounting with the bonnet above and service-access space before choosing line size. FITOK describes the CL series as having reverse-flow coefficient below 0.1% of its forward-flow coefficient. Unlike the spring-set series in this catalog, the CL feature list gives no nominal opening-pressure choice; obtain the selected valve's opening/reseal behavior for the actual flow and orientation rather than copying another series' setting.
Configuration options
The catalog lists CLSS-FL4, FL6 and FL8 tube-fitting examples with separate dimensions. The shown photo is not tied to one of those codes, so size, end type and final material/seat construction must be reconciled to the actual drawing.
Application limits
The reverse/forward flow-coefficient ratio is a manufacturer series description, not an installed leakage certificate or a cracking-pressure rating. Its pressure maximum and temperature span are separate references, not one simultaneous duty. Check the selected valve curve, fluid compatibility, orientation and inspection criteria.




