GESTRA RK76 is a high-performance wafer-type non-return check valve designed for industrial piping systems. It reliably prevents reverse flow of liquids, gases, and steam. The valve uses a lift-style disco design with a spring-assisted closing mechanism, supports installation in any position (horizontal or vertical), and uses a spiral centering ring for precise alignment. RK76 complies with the EU PED Pressure Equipment Directive and EN 558-1. With an extremely short face-to-face length (basic series 49), compact dimensions, and low weight, it is well suited for steam systems, chemical piping, and fluid transfer applications.

In hot-water circulation, condensate recovery, mineral oil transfer, and corrosive gas applications, GESTRA RK76 provides low opening pressures (2.5–18 mbar) and zero-leakage protection to support safe and stable system operation. Multiple seat material options (metal-to-metal, PTFE, EPDM, FPM) accommodate different media requirements. Pressure ratings include PN 6/10/16/25/40 and ASME CL 125/150/300.

Keywords: GESTRA RK76 check valve, wafer check valve, stainless steel check valve, wafer check valve, steam check valve, industrial non-return valve.

Key Features and Benefits

• Compact design: Face-to-face lengths of only 16–60 mm (depending on DN) make the valve suitable for clamped installation between flanges, saving space and reducing system weight.

• Flexible installation: The built-in stainless steel spring supports installation in any orientation. The springless version is suitable for vertically upward flow and adapts to complex piping layouts.

• Low opening pressure: Standard opening pressure is 2.5–6.5 mbar (springless) or 5–18 mbar (with spring). Special springs rated at 20–1000 mbar are also available to ensure reliable opening at minimum flow rates.

• Durable materials: The body is made from 1.4107 chromium steel (DIN/EN) or SA217 CA15 (ASME). The disc and spring are made from 1.4571 stainless steel, providing strong corrosion resistance for extreme environments from -190°C to 300°C.

• Zero-leakage protection: In accordance with DIN EN 12266, metal seats achieve Class D leakage rates, while soft seats (EPDM/FPM) achieve Class A, helping prevent equipment damage or efficiency losses caused by reverse flow.

• Customization options: Available options include silicone-free/grease-free versions, pickling and passivation treatment, orifice and bore designs, and ASME RF sealing strips for specific industrial requirements.

These features make GESTRA RK76 a reliable industrial solution with reduced maintenance requirements.

Technical Specifications

Pressure/Temperature Ratings

Standard	Pressure rating	Temperature range	Maximum pressure (barg) example
DIN/EN	PN 40	-10°C to 300°C	40.0 (-10°C) to 25.8 (300°C)
ASME	CL 300	-10°C to 300°C	49.6 (-10°C) to 31.6 (300°C)

Dimensions and Weight

Nominal size DN (mm)	Inches	Face-to-face length L (mm)	Flange diameter ∅ D (PN 6-40, mm)	Weight (kg)
15	½	16	45	0.18
20	¾	19	55	0.30
25	1	22	65	0.45
32	1¼	28	75	0.70
40	1½	31.5	85	0.90
50	2	40	98	1.50
65	2½	46	118	2.10
80	3	50	134	3.40
100	4	60	154	5.20

• Nominal size range: DN 15–100 mm (NPS ½–4).

• Connection standards: DIN EN 1092 B (PN 6/10/16/25/40), ASME B16.5 (CL 150/300 RF), BS 10 (Table D/E/F/H/J), JIS B2238 10K.

• Seat options:

Type	Temperature range	Leakage rate (DIN EN 12266)
Metal-to-metal	-10°C to 300°C	Class D
PTFE	-190°C to 250°C	Class D
EPDM	-40°C to 150°C	Class A
FPM	-25°C to 200°C	Class A

Materials

• Body/seat/guide: 1.4107 chromium steel (DIN/EN) / SA217 CA15 (ASME).

• Disc/spring retainer: 1.4571 stainless steel.

• Spring: Stainless steel.

• Spiral centering ring: 1.4310 chromium steel.

Applications

GESTRA RK76 is widely used in:

• Steam and condensate systems: Preventing reverse steam flow and protecting pumps and heat exchangers.

• Chemical and petroleum piping: Handling mineral oil, gases, and corrosive fluids for safe transfer.

• Industrial gas and air lines: Providing reliable closure at low differential pressure for compressed-air systems.

• Water treatment and HVAC: EPDM/PTFE seat options are suitable for water and neutral media.

Note: Not recommended for severe pulsating flow or high differential-pressure applications. For DN 65/80, selecting a smaller size is recommended to optimize performance.

Installation and Maintenance Guide

Installation Steps

• Confirm that the media flow direction matches the arrow on the valve body.

• Position the valve between two flanges. Use standard gaskets and long bolts, and tighten evenly in a diagonal sequence according to the flange standard torque requirements.

• Install only when system pressure is zero. The spring-loaded version can be installed in any orientation; the springless version is limited to vertically upward flow.

• Verify the minimum volumetric flow required to keep the disc open (see the data sheet for details).

Maintenance Recommendations

• Regular inspection: Clean the disc and seat every 6–12 months and check spring integrity.

• Troubleshooting:

Leakage: Remove foreign matter or replace the seat.

• Failure to open: Check spring pressure or media viscosity.

• Component replacement: The cover can be removed for convenient spring or disc replacement. Use original manufacturer parts to ensure compatibility.

Proper maintenance can extend RK76 service life to more than 10 years.

Related Document Downloads

• Official Data Sheet (PDF)：Complete specifications, drawings, and installation diagrams.

• GESTRA Official Product Page：Additional variants and selection tools.

• Technical Manual PDF：Detailed dimensions and pressure curves.