INSTRUMENTATION > FLOW > CFS925 & CFS926 Series Piston Type Switch

CLARK SOLUTIONS

CFS925 & CFS926 Series Piston Type Switch

Liquid Flow rates from 0.1 GPM to 1.5 GPM, Gases to 25 SCFM

DESCRIPTION

These two series of precision-calibrated switches provide reliable and consistent performance; repeatability is within 1%. CFS-925 and CFS-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.

The CFS-925 series is a general purpose design for liquids or gases. The CFS-926 Series features a special low-flow piston. This additional piston allows the detection of fluid flow as low as 50 cc/min. These switches are ideal for applications such as gas sampling, liquid or gas leak detection, or chemical injection.

Click here for information on our other flow switches.

SPECIFICATIONS

Wetted Materials:
     Housing: Brass or 316 Stainless Steel
     Piston In Brass Housing: Polysulfone for 
          water; Brass for oil or air
     Piston in Stainless Steel Housing: 316 
           Stainless Steel
     Low Flow Piston (CFS-926): Same as 
            Housing
     Spring: 316 Stainless Steel
     O-Ring: Viton®
     Other Wetted Parts: Epoxy
Pressure Rating:
     Max. Operating: 1000 PSIG
     Proof: 2500 PSIG
     Burst: 5000 PSIG
Operating Temperature:
     With Brass or S.S. Piston: -20°F to +300°F 
          (-29°C to +148.9°C)
     With Polysulfone Piston: -20°F to +225°F 
          (-29°C to +107.2°C)
Repeatability: 1% Maximum Deviation
Set Point Accuracy: ±10%
Set Point Differential: 15% Maximum
Switch: SPDT, 20 VA




  

    
      Switch
      Rating, Maximum Resistive Load
  

  

    
      VA
    
      Volts
    
      Amps AC
    
      Amps DC
  

  

    
      20
    
      0-30
    
      0.4
    
      0.3
  

  

    
      120
    
      0.17
    
      0.13
  

  

    
      240
    
      0.08
    
      0.06
  



Inlet/Outlet Ports: 1/4" NPT
Electrical Termination: No. 18 AWG, 24" L., 
     Polymeric Lead Wires
Lap-Fitted Piston Type Switch

An additional lap-fitted piston is used in model CFS-926 to accurately detect low flow rates. Calibration is determined by one or more metering holes in the end of the low-flow piston which regulate bypass flow and therefore the actuation setting. 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.

Flow Setting, Air (Typical)
Dependent on operating line pressure. Examples of set point ranges at a given line pressure are shown below.

Line Pressure Actuation Point
CFS-925 CFS-926
Min. Max. Min. Max.
5 PSIG (Minimum Line Pressure) 0.5 SCFM 10 SCFM 2 SCFH 15 SCFH
100 PSIG 1.5 SCFM 25 SCFM 7 SCFH 50 SCFH

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.

Piston Type Switch Typical Pressure Drop

HOW TO ORDER - STANDARD MODELS - WATER CALIBRATION

Specify Part Number based on desired housing material and flow setting.

Liquids other than water: Special calibration is available from Clark for media other than water. Please consult us 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 us 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.

FOR YOUR CONVENIENCE, THESE ITEMS ARE AVAILABLE ONLINE OR PLEASE CALL 1-800-253-2497 TO ORDER
Model Part Numbers Flow Setting GPM, ±10%
Brass 316 SS
CFS-925 C26914 C26926 0.10
C26915 C26927 0.25
C26916 C26928 0.50
C26917 C26929 0.75
C26918 C26930 1.00
C26919 C26931 1.50



FOR YOUR CONVENIENCE, THESE ITEMS ARE AVAILABLE ONLINE OR PLEASE CALL 1-800-253-2497 TO ORDER
Model Part Numbers Flow Setting
Brass 316 SS cc/Min., ±10% Equiv. GPM
CFS-926 C26938 C26951 50 0.013
C26939 C26952 100 0.025
C26941 C26953 150 0.045
C26942 C26954 200 0.055
C26943 C26955 250 0.065
C26944 C26956 300 0.075

Qty:

Show Discount Schedule

CFS-925 and CFS-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, explosion-proof junction box for Class I, Division 1, Group D hazardous locations. Units must be assembled completely at factory.