Check Valve SHPI CVPF 03-03 – Pneumatic, G 3/8″ × G 3/8″, 10 bar, Brass+NBR

A Problem You’ve Already Faced

• Pressure “runs away” in reverse — without a check valve on a branched pneumatic line, when pressure drops in one branch, air migrates from another — pressure at the consumer becomes unstable.
• The cylinder “drifts” when pressure is released — without a check valve, a loaded pneumatic cylinder slowly expels air back through the system after the supply is cut.
• Bought a “similar” valve — wrong thread — ordered G 3/8″ female instead of male, or confused it with R 3/8″ (taper) — the valve didn’t fit the mating port.
• Valve leaks after installation — a cheap equivalent with poor NBR sealing doesn’t provide zero leakage in the closed position at 8–10 bar.
• Required part not in local stock — a small component holds up the launch of the entire automation system.

A check valve is the “one-way gate” of a pneumatic system. Without the right valve, pressure stability is compromised, unintended actuator movement can occur and backflow surge damage is possible when the system stops.

What Is the SHPI CVPF 03-03

The SHPI CVPF 03-03 is a pneumatic check valve (non-return valve) from the CVP series by SHPI (Shan Hua Plastic Industrial Co., Taiwan, ISO 9001, RoHS). The valve is part of the One Touch Fittings catalogue and is designed for installation in pneumatic control and air supply lines.

Part number breakdown — CVPF 03-03:

• CV — Check Valve (non-return valve);
• P — Push-In / Pneumatic — SHPI pneumatic valve series;
• F — Female thread — one or both ports with internal thread;
• 03 (first) — inlet port size: G 3/8″ (code 03 in SHPI system);
• 03 (second) — outlet port size: G 3/8″.

Operating principle: a ball or poppet sealing element inside the body is held against the seat by a spring. When inlet pressure exceeds the cracking pressure — the element lifts and air flows through. When pressure drops or reverse flow is attempted — the spring closes the valve. Cracking pressure: 0.05 MPa (0.5 bar).

Body marking: an arrow indicating the permitted flow direction — this must be observed during installation.

Technical Specifications

💡 Expert tip: the CVPF 03-03 has female G 3/8″ threads on both ports — installation requires two male G 3/8″ nipples on both sides. Always observe the flow direction marked by the arrow on the body: a valve installed “backwards” blocks the line completely and the compressor cannot pressurise the circuit. Thread seal: PTFE tape, 2–3 wraps.

Brand Equivalents

Why Acvatron SRL — 5 Solid Reasons

Original SHPI Components with Certificates

Acvatron SRL supplies SHPI fittings and valves with ISO 9001 and RoHS documents. The CVPF 03-03 is not an anonymous product — it comes from a Taiwanese manufacturer with 40 years of history and confirmed specifications.

Engineering Selection by System Diagram

Not sure of the thread type or flow direction — send a photo or drawing and the Acvatron SRL engineer selects the correct part number and confirms mounting orientation on the same day.

In Stock at the Chișinău Warehouse

SHPI CVP series valves in G 1/4″, G 3/8″, G 1/2″ are permanently in stock at acvatron.md. Collect on the day of payment.

Full SHPI Range for Pneumatic Systems

Acvatron SRL supplies the complete SHPI range: PU and PA tubing, One-Touch fittings PC/PL/PT series, CVP check valves, regulators and reels. Complete pneumatic line supply from one source.

Documents for Legal Entities

All items are supplied with accompanying documents. For legal entities — invoice and contract.

Applications

Industrial Automation

• Separating pneumatic circuits: preventing cross-flow between independent branches
• Holding cylinder pressure when main line pressure drops
• Protection against pressure surge when directional valves switch rapidly

Machine Tools and Machining Centres

• Check valve on the receiver outlet to prevent backflow when the compressor stops
• Separating control and supply circuits on CNC machines

Compressed Air Preparation Systems

• Fitted in the line after the receiver to prevent backflow when multiple compressors run in parallel
• Protecting filters and dryers from back-pressure

Transportation Pneumatics

• Braking and control systems of pneumatically actuated vehicles
• Separating independent circuits in pneumatic brake systems

Expert Opinion

“The check valve is the component most often fitted ‘any way round’, without checking the arrow. The result: the compressor feeds the system but pressure won’t build up — people assume the compressor is undersized. First rule of installation: the arrow on the body always points in the direction of flow from the compressor to the consumer. Second rule: G thread needs sealing, Rc does not. If your layout mixes G and Rc ports — prepare the transition fittings in advance. And third: don’t cut corners on air quality. One good water-oil separator upstream of the check valve — and the valve will last 5–10 years without replacement. Without filtration, the NBR seal swells from oil contamination within 1–2 years.”

Vitali Bolucevschi, Chief Engineer at Acvatron SRL, 15 years in the industry

How to Install the CVPF 03-03 Check Valve Correctly: 5-Step Procedure

1. Identify the flow direction — locate the arrow on the body: it shows the permitted direction. “Inlet” — the port facing the compressor; “outlet” — toward the consumer.
2. Prepare the threaded connections — wrap PTFE tape on the male threads of the nipples, 2–3 wraps in the thread direction.
3. Install the valve — tighten into the mating ports; torque 15–20 N·m for G 3/8″. Do not over-tighten.
4. Apply pressure and verify — the valve opens above 0.5 bar. On pressure release: reverse flow through the valve must be zero.
5. Check thread seal integrity — apply soapy solution to both ports under working pressure: bubbles are not acceptable.

FAQ

❓ What is the difference between the SHPI CVPF 03-03 and a compressor check valve (type 1/2″ × 19 mm)?

These are two fundamentally different valves. The CVPF 03-03 is a pneumatic check valve for pipe lines: both ports are threaded G 3/8″, 10 bar, compact body. The compressor check valve (1/2″ × 19 mm) is fitted between the piston block and the receiver: one port is threaded (into the receiver), the other accepts a 19 mm hose tail. The function is the same — one-way flow — but the design and application are entirely different.

❓ Can the CVPF 03-03 be used in vacuum systems?

No. The cracking pressure is 0.05 MPa (0.5 bar positive). In vacuum systems (below atmospheric) the valve will not open correctly — dedicated vacuum check valves with a zero or negative cracking pressure are required.

❓ How often does the CVPF 03-03 need servicing or replacement?

With correct air quality (ISO 8573-1) and normal temperatures, no scheduled maintenance is required. Replace when leakage in the closed position appears, or when the valve sticks (fails to open below 2–3 bar instead of 0.5 bar). Recommended inspection: once a year at any scheduled pneumatic line maintenance.