Pressure Cap: Temperature Range -40°C to 130°C

Component Specifications

Definition

The pressure cap is a critical component installed on coolant reservoirs or tanks in industrial machinery cooling systems. It functions as a pressure-regulating valve that maintains system pressure above atmospheric levels, raising the boiling point of the coolant to prevent vaporization during high-temperature operation. The cap typically incorporates a pressure relief valve that opens at a predetermined pressure to prevent over-pressurization and a vacuum valve that allows coolant to return from the expansion tank as the system cools.

Working Principle

The pressure cap operates on the principle of pressure regulation through spring-loaded valves. When coolant temperature increases, pressure builds within the closed system. The cap's pressure relief valve remains closed until reaching the designed pressure rating, maintaining optimal pressure for heat transfer efficiency. If pressure exceeds the set point, the valve opens to vent excess pressure to the expansion tank or atmosphere. During cooling, the vacuum valve opens to allow coolant return, preventing vacuum formation that could collapse hoses or components.

Materials

Typically constructed from brass, stainless steel, or high-temperature plastics with nitrile or silicone rubber gaskets. Pressure springs are usually stainless steel. Materials must resist corrosion from coolants and withstand operating temperatures from -40°C to 130°C.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Thread Size	M30x1.5, M32x1.5, or custom
Pressure Rating	7-15 psi (0.5-1.0 bar)
Temperature Range	-40°C to 130°C
Vacuum Valve Opening	0.5-2.0 in-Hg
Relief Pressure Tolerance	±1 psi

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 6194, DIN 71412

Parent Products

This component is used in the following industrial products

Coolant Reservoir/Tank

A container that stores and supplies coolant fluid to maintain proper levels in the cooling system.

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Engineering Analysis

Risks & Mitigation

Over-pressurization causing component failure
Coolant boiling leading to overheating
Vacuum collapse of hoses
Coolant leakage and environmental contamination

FMEA Triads

Trigger: Gasket degradation from heat and chemical exposure
Failure: Pressure loss leading to coolant boiling
Mitigation: Regular inspection and replacement of gaskets, use of compatible coolant formulations

Trigger: Spring fatigue from cyclic loading
Failure: Inconsistent pressure regulation
Mitigation: Periodic pressure testing, scheduled replacement based on operating hours

Trigger: Corrosion of metal components
Failure: Sticking valves or leakage
Mitigation: Use corrosion-resistant materials, proper coolant maintenance, environmental controls

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Pressure relief setting ±1 psi, vacuum valve opening ±0.5 in-Hg

Test Method

Pressure decay test per ISO 6194, visual inspection of gaskets and springs, torque verification of sealing surfaces

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Pressure Cap

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Shenzhen Deerose Technology Co., Ltd.

Shenzhen, Guangdong, CN

Also makes: Pressure Control Valve, Pressure Relief Valve, Fuel Injection Pump and 9 more

Listed on the company's own website · profile compiled by CNFX from public sources

Listed there as: “Pressure Cap Socket”
View source page ↗ szdeerose.com · checked 2026-09-08

View profile Send enquiry

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What happens if a pressure cap fails?

A failed pressure cap can cause coolant boiling at lower temperatures, reduced cooling efficiency, coolant loss through overflow, or system over-pressurization leading to hose bursts or component damage.

How often should pressure caps be replaced?

Pressure caps should be inspected annually and replaced every 2-3 years or according to manufacturer recommendations, as gaskets degrade and spring tension decreases over time.

Can using the wrong pressure rating damage the cooling system?

Yes, a cap with too low pressure rating causes premature boiling, while too high rating risks over-pressurization and component failure. Always use manufacturer-specified pressure ratings.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Pressure Cap