FS-925 Series - General Purpose Flow Rate Settings: Liquids: 0.1 GPM to 1.5 GPM Air/Gases: See Flow Settings at right FS-926 Series - Low Flow ed pprov UL A on-Proof si Explo Port Size: 1/4 NPT Primary Construction Material: Brass or Stainless Steel Setting Type: Fixed Flow Rate Settings: Liquids: 50-300 cc/min. Air/Gases: See Flow Settings at right U.L. Recognized -- File No. E31926 CSA Listed -- File No. LR30200 FM Approved -- File No. 1H3A2.AX and 0A8A3AE FS-925/926 Series These two series of precision-calibrated switches provides reliable and consistent performance; repeatability is within 1%. FS-925 and FS-926 units are factory preset for actuation at specified flow rates. These switches provide accurate detection of excessive or insufficient flow rates in such applications as: protecting against loss of fluid flow in hydraulic systems, assuring proper coolant flow in semiconductor processing equipment, monitoring high pressure lubrication systems, and ensuring proper air flow in water/waste systems. Specifications Wetted Materials Housing Piston In Brass Housing Stainless Steel Housing Low Flow Piston (FS-926) FLOW SWITCHES Spring O-Ring Other Wetted Parts Pressure Rating Operating, Maximum Proof Burst Operating Temperature With Brass or S.S. Piston With Polysulfone Piston Brass or 316 Stainless Steel Polysulfone for water; Brass for oil or air 316 Stainless Steel Viton(R) Epoxy Both the FS-925 and FS-926 use a spring-loaded piston to detect positive flow with great precision. They act upon direct fluid flow and will not show "falsepositive" flow indication as can happen with sensors using indirect sensing methods such as pressure measurement. The FS-926 incorporates an additional lap-fitted piston for very low flows; see below. 1000 PSIG (69 bar) Dimensions 316 Stainless Steel Same as Housing 5000 PSIG (345 bar) -20F to +300F (-29C to +148.9C) 1% Maximum Deviation Set Point Accuracy 10% Set Point Differential 15% Maximum Switch* SPDT, 20 VA Inlet/Outlet Ports 1/4 NPT Electrical Termination No. 18 AWG, 24 L., Polymeric Lead Wires 4-1/8" (104.7 mm) 1-1/4" (31.7 mm) 27/32" (21.4 mm) Double Piston Detects Minute Flow - FS-926 MAGNET CARRIER PISTON An additional, lap-fitted piston is used in Gems FS-926 Series to accurately detect low-flow rates. Calibration is determined by one or more metering holes in the end of the lowflow piston, which regulate bypass flow, and therefore the actuation setting. 1/4" NPT BOTH PORTS 3/4" (19.0 mm) 1" (25.4 mm) 1-3/4" (44.4 mm) Electrical Connection, 1/2 NPT Conduit When metered bypass flow is exceeded, the resultant pressure differential displaces the low-flow piston, moving the magnet carrier piston to actuate the reed switch. Two large bypass holes in the piston skirt are exposed after actuation to maintain low pressure drop. G-10 2-3/8" (60.3 mm) 1/2" (12.7 mm) *See "Electrical Data" on Page X-5 for more information. BY-PASS HOLES METERING ORIFICE LOW-FLOW PISTON 9/32" DIA. (7.1 mm) MTG. HOLES (2) -20F to +225F (-29C to +107.2C) Repeatability O-RING 1/4" (6.3 mm) 2500 PSIG (172 bar) Visit www.GemsSensors.com for most current information. 1/2" (12.7 mm) PISTON TYPE Flow Settings, Air (Typical) Pressure Drop - Typical Dependent on operating line pressure. Examples of set point ranges at a given line pressure are shown below. FS-925 Series Line Pressure FS-925 FS-926 Min. Max. Min. Max. 5 PSIG (Minimum) 0.5 SCFM 10 SCFM 2 SCFH 15 SCFH 100 PSIG 1.5 SCFM 25 SCFM 7 SCFH 50 SCFH 4 PRESSURE DROP (PSID) Actuation Point Part No. 26919 3 Part No. 26917 2 1 Part No. 26914 Minimum 5 PSI line pressure required. 0 0.05 Gas Calibration Water flow units should not be used for air/gas applications: Gas flow units have a special dash-pot piston for reliable operation. Gas calibration is dependent upon line pressure, switch orientation, and the specific type of gas. The calibrated flow set point is subject to change with fluctuations in line pressure. How To Order - Standard Models - Water Calibration .75 1.0 1.5 2 FLOW RATE - GPM Tests conducted with units in vertical position (lead wires up) with water at +70F (21C). FS-926 Series FS-925 Series - General Purpose PRESSURE DROP (PSID) 2.0 Specify Part Number based on desired housing material and flow setting. Liquids other than water: Special calibration is available from GEMS for media other than water. Please consult factory with your requirements, including housing material (brass or stainless steel), flow media, operating pressure, flow set point and liquid viscosity (SSU). A lot charge will be applied for special calibrations. Gas flow: Consult factory for available calibrations. Specify: Housing material (brass or stainless steel), gas type, mounting orientation, operating pressure and actuation setting (SCFM or SCFH) and normal flow rate. A lot charge will be applied for special calibrations. Part No. 26938 1.5 Part No. 26941 Part No. 26944 1.0 0.5 0 0 50 100 150 200 250 300 350 400 FLOW RATE - cc/Min. Tests conducted with units in vertical position (lead wires up) with water at +70F (21C). Brass 316 S.S. 0.10 26914 26926 0.25 26915 26927 0.50 26916 26928 0.75 26917 26929 1.00 26918 26930 1.50 26919 26931 FS-925 and FS-926 switches are U.L. Approved for Class I, Division 2, Groups A, B, C, D hazardous locations. They are also available with FM-approved, explosionproof junction box for Class I, Division 1, Group D hazardous locations. Units must be assembled completely at GEMS. U.L. Approved -- File No. E183854 FS-926 Series - Low Flow FLOW SWITCHES Part Numbers Flow Settings GPM, 10% Standard Wiring Color Code Flow Setting Part Numbers Wire Color Terminal cc/Min. 10% Equiv. GPM Brass Material 316 S.S. Material Orange N.O. 50 .013 26938 26951 Black Common 100 .025 26939 26952 Red N.C. 150 .045 26941 26953 200 .055 26942 26954 250 .065 26943 26955 300 .075 26944 26956 Notes: 1. Flow settings are calibrated using water @ +70F on increasing flow, with units in a vertical position (lead wires up). Consult factory regarding special flow setting calibration. 2. Temperature changes will slightly affect the standard water or gas flow settings listed. Oil flow settings will vary with viscosity. 3. Use of 50 micron filtration is recommended. - Stock Items. Visit www.GemsSensors.com for most current information. G-11