U.S. PATENT NO. 4,315,520
F-4103 Series
Spring Biased Comparators
The F-4103 Series spring-biased comparators function as high-precision regulators with an adjustable positive or negative bias. Standard units operate at a 1:1 ratio (plus/minus bias), with specialized 3:1 and 5:1 ratios available. These units are ideal for HVAC and unique control applications requiring a specific pressure offset.
Operating Logic
- Constant Bleed, Relieving design
- Supports 1:1, 3:1, and 5:1 ratios
- Positive or Negative offset control
- Accepts Pilot/Control inputs
Technical Specs
- Repeatability: < ± 0.05 PSI
- Max Supply: 35 PSI (242 kPa)
- Low Drift: < 0.03 PSI (24 hours)
- Rec. Filtration: 5 Micron
Technical Specifications
| WETTED MATERIALS | Polysulfone, Silicone, Stainless Steel |
| SUPPLY VARIATION | < 0.02 PSI per 1 PSI change (dead-ended) |
| TEMPERATURE RANGE | 40° - 150° F (4° - 66° C) |
| STEM OPTIONS | Non-rising; Adjusting Knob, 1/4" Shaft, or Flush Shaft |
Ordering Information
F-4103-[ID]
Bias Range / Ratio
[Adjustment]
W/K (Knob)
W/S (Shaft)
W/OS (Flush)
W/S (Shaft)
W/OS (Flush)
[Ports]
P80 (1/16")
P85 (1/8")
P85 (1/8")
30: -5 to 5 PSI
33: -5 to 10 PSI
36: -5 to 20 PSI
39: -13 to 20 PSI
40: 0-20 PSI (3:1 Ratio)
50: 0-20 PSI (5:1 Ratio)
Example: F-4103-30-W/K-P80
(-5 to 5 PSI bias, with knob and 1/16" barbs)
* Standard units include straight connections for 1/16" ID tubing.