Circle Seal 5133B-xMP Relief Valve
5100 Series: Adjustable Popoff & Inline Relief Valves, 10 to 2400 psig
Features:
- Zero leakage: to 95-98% of cracking pressure
- Positive reseat: reseals at high percentage of the cracking pressure
- Accurate set pressure: valves can be pre-set to required cracking pressure
- Adjustable: interchangeable springs permit change of crack pressure range; tamper-proof adjustment inside of valve
- Excellent flow characteristics: lift ring poppet design allows high flow rates with minimum amount of pressure rise
- No chatter: chatter eliminated through use of friction damping device; damping bars prevent poppet from over-travel at initial cracking thrust; damping load is proportional to spring load
- Minimal maintenance: fluid is not throttled across the seal, which, combined with soft seat and poppet design, prevents seat and seal erosion
- Versatile: vent-to-atmosphere or inline connections; various materials for both body and seals; sizes ranging from 1/8″ to 1-1/4″
- PED certifications and CE marking available for most models: add “PED” prefix to the valve part number if required

Circle Seal 5133B-xMP Relief Valve Technical Data:
- Description: Inline Relief Valve, 1/8″ to 1-1/4″ MNPT x FNPT connections, constructed in Brass with Neoprene seals, cracking pressures between 10 to 2400 psig
- Configuration: Inline
- Max. Operating Pressure: 2400 psig (except 1-1/4″ size, which is limited to 1200 psig)
- Body Material: Brass
- Seal Material: Neoprene
- Cracking Pressure: 10 to 2400 psig (REQUIRED SET PRESSURE MUST BE SPECIFIED)
- Cracking Pressure Tolerance: ±5% (except cracking pressures below 20 psi, which have a tolerance of ±20%)
- Flow at Cracking Pressure (Elastomeric seals): 5 cc/min
- Reseal Pressure (Elastomeric seals):
- Cracking pressures less than 100 psi: 70% to 89% of cracking pressure
- Cracking pressures greater than 100psi: 90% of cracking pressure
- Leakage at reseal pressure (Elastomeric seals):
- Ascending pressure: zero up to 95% of cracking pressure
- Descending pressure: zero at reseal pressure and below
- Temperature: -40F to +300F
Cracking / Reseal Pressure Graphs:



Flow Rate Table:
Dimensional Information:

Notes:
- The reseal point is the point at which the valve seals absolutely tight so that there is no leakage detectable by normal means of measurement. The point at which the valve closes, cutting off virtually all flow, is called the reseat point. The reseat point is substantially above the reseal.
- Proper filtration is recommended to prevent damage to sealing surfaces.
- Cracking pressure on initial crack after standing un-actuated for a prolonged period will be higher than the set pressure.
- For PED applications, Brass bodies are limited to a max temp of +100F.
Please contact our Sales Department for assistance in selecting the right products for your application.
Product Catalog: Circle Seal Relief Valves
Service Information Sheet: Circle Seal 5100-Series Relief Valves




