FLOW SWITCHES 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 Port Size: 1/4 NPT Primary Construction Material: Brass or Stainless Steel Setting Type: Fixed U.L. Recognized File No. E31926 Flow Rate Settings: Liquids: 50-300 cc/min. CSA Listed File No. LR30200 Air/Gases: See Flow Settings at right FM Approved File No. 1H3A2.AX FS-925/926 Series and 0A8A3AE 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 ufl id ofl w in hydraulic systems, assuring proper coolant ofl w in semiconductor processing equipment, monitoring high pressure lubrication systems, and ensuring proper air flow in water/waste systems. Specifications Wetted Materials Housing Brass or 316 Stainless Steel Piston In Brass Housing Polysulfone for water Brass for oil or air Both the FS-925 and FS-926 use a spring-loaded Stainless Steel Housing 316 Stainless Steel piston to detect positive flow with great precision. They act upon direct fluid flow and will not show false- Low Flow Piston (FS-926) Same as Housing positive flow indication as can happen with sensors Spring 316 Stainless Steel using indirect sensing methods such as pressure O-Ring Viton measurement. The FS-926 incorporates an additional Other Wetted Parts Epoxy lap-fitted piston for very low flows see below. Pressure Rating Operating, Maximum 1000 PSIG (69 bar) Dimensions 1/4 (6.3 mm) Proof 2500 PSIG (172 bar) Burst 5000 PSIG (345 bar) Operating Temperature With Brass or S.S. Piston -20F to +300F (-29C to +148.9C) 9/32 DIA. (7.1 mm) MTG. HOLES (2) With Polysulfone Piston -20F to +225F (-29C to +107.2C) Repeatability 1% Maximum Deviation 4-1/8 (104.7 mm) 2-3/8 Set Point Accuracy 10% (60.3 mm) Set Point Differential 15% Maximum Switch* SPDT, 20 VA 1/2 (12.7 mm) Inlet/Outlet Ports 1/4 NPT Electrical Termination No. 18 AWG, 24 L., Polymeric Lead Wires 1-1/4 (31.7 mm) *See Electrical Data on Page X-5 for more information. 27/32 (21.4 mm) 1/4 NPT G-11b ill BOTH PORTS Double Piston Detects Minute Flow FS-926 3/4 (19.0 mm) An additional, lap-fitted piston is used in Gems 1 MAGNET CARRIER O-RING FS-926 Series to accurately (25.4 mm) PISTON detect low-flow rates. Calibration is determined 1-3/4 (44.4 mm) by one or more metering holes in the end of the low- BY-PASS HOLES flow piston, which regulate Electrical Connection, 1/2 NPT Conduit METERING ORIFICE bypass flow, and therefore LOW-FLOW the actuation setting. PISTON 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 1/2 pressure drop. (12.7 mm) G-10 Visit www.GemsSensors.com for most current information. UL Approved Explosion-ProofPISTON TYPE Flow Settings, Air (Typical) Pressure Drop - Typical Dependent on operating line pressure. Examples of set point ranges at a given line FS-925 Series pressure are shown below. 4 Actuation Point Line FS-925 FS-926 Part No. 26919 3 Pressure Min. Max. Min. Max. Part No. 26917 2 5 PSIG (Minimum) 0.5 SCFM 10 SCFM 2 SCFH 15 SCFH 100 PSIG 1.5 SCFM 25 SCFM 7 SCFH 50 SCFH 1 Part No. 26914 Minimum 5 PSI line pressure required. 0 Gas Calibration 0.05 .75 1.0 1.5 2 FLOW RATE - GPM Water flow units should not be used for air/gas applications: Gas flow units have a Tests conducted with units in vertical position (lead wires up) with water at +70F (21C). 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. FS-926 Series How To Order Standard Models Water Calibration 2.0 Specify Part Number based on desired housing material and flow setting. Part No. 1.5 26938 Liquids other than water: Special calibration is available from GEMS for media other Part No. 26941 Part No. 26944 than water. Please consult factory with your requirements, including housing material 1.0 (brass or stainless steel), flow media, operating pressure, flow set point and liquid viscosity (SSU). A lot charge will be applied for special calibrations. 0.5 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 0 0 50 100 150 200 250 300 350 400 calibrations. FLOW RATE - cc/Min. Tests conducted with units in vertical position (lead wires up) with water at FS-925 Series General Purpose +70F (21C). Part Numbers Flow Settings GPM, 10% Brass 316 S.S. FS-925 and FS-926 switches are U.L. Approved for 0.10 26914 26926 Class I, Division 2, Groups A, B, C, D hazardous locations. 0.25 26915 26927 They are also available with FM-approved, explosion- 0.50 26916 26928 proof junction box for Class I, Division 1, Group 0.75 26917 26929 D hazardous locations. Units must be assembled 1.00 26918 26930 completely at GEMS. U.L. Approved File No. E183854 1.50 26919 26931 FS-926 Series Low Flow 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. G-11 Visit www.GemsSensors.com for most current information. PRESSURE DROP (PSID) PRESSURE DROP (PSID) FLOW SWITCHES