Z2FS22-3X/S2 | Rexroth Throttle Check Valve 350bar 360L/min

Product Overview

The Z2FS22-3X/S2, Z2FS22-3X/S, Z2FS22-30B/S2, and Z2FS22-30B/S are core models in the Bosch Rexroth Z2FS series of double throttle check valves in sandwich plate design. Z2FS 22 corresponds to NG25 nominal size, 3X series (30–39) or 30 series, with mounting pattern conforming to DIN 24340 form A, ISO 4401, and CETOP-RP 121H standards. These valves are used to limit the flow in one or two actuator ports.

The Z2FS 22 features two symmetrically arranged throttle check valves—limiting flow in one direction (via adjustable throttling spools) while allowing free return flow in the opposite direction. Depending on the suffix “S” or “S2”, the throttling effect occurs either in the supply (meter-in) or return (meter-out) flow. The throttling spool is axially adjusted via a hexagon socket setting screw to vary the throttle opening.

As original Bosch Rexroth sandwich throttle check valves, these products offer complete interchangeability within the same series and size, requiring no modifications to mounting interfaces or piping layouts.

Model Code Breakdown:

• Z2FS – Double throttle check valve in sandwich plate design

• 22 – Size 22 (corresponds to NG25)

• 3X / 30 – 3X series (30–39, unchanged installation and connection dimensions) / 30 series abbreviation

• B – Specific configuration/design code

• S – Meter-in control (supply throttling)

• S2 – Meter-out control (return throttling)

About Z2F / Z2FS Series:

Z2F and Z2FS are the same product family, with Z2FS representing the standardized upgrade of Z2F—sharing identical mounting dimensions and performance specifications, differing primarily in standardized sealing materials and surface treatment options. Z2FS 22 offers NBR (standard) and FKM (V suffix) seal options.

Technical Specifications 

Z2FS22 Series Common Specifications:

• Brand: BOSCH REXROTH

• Series: Z2FS Series

• Product Type: Double Throttle Check Valve in Sandwich Plate Design

• Nominal Size: 22 (corresponds to NG25)

• Component Series: 3X (30–39)

• Mounting Standard: DIN 24340 Form A / ISO 4401 / CETOP-RP 121H

• Maximum Operating Pressure: 350 bar

• Maximum Flow: 360 L/min

• Mounting Type: Sandwich Plate / Stack Mounting

• Adjustment Type: Hexagon socket setting screw

• Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD mineral oils

• Seal Material: NBR (standard) / FKM (V suffix, optional)

• Weight: Approx. 8 kg

• Height: 55 mm

Z2FS22-3X/S2 Specifications:

• Model: Z2FS22-3X/S2

• Material Number: R900431176

• Throttling Mode: Meter-out Control (return throttling)

• Component Series: 3X

• Weight: Approx. 8 kg

Z2FS22-3X/S Specifications:

• Model: Z2FS22-3X/S

• Material Number: R900456783

• Throttling Mode: Meter-in Control (supply throttling)

• Component Series: 3X

• Weight: Approx. 8 kg

Z2FS22-30B/S2 Specifications:

• Model: Z2FS22-30B/S2

• Throttling Mode: Meter-out Control (return throttling)

• Component Series: 30 (belongs to 3X series)

• Design Code: B

Z2FS22-30B/S Specifications:

• Model: Z2FS22-30B/S

• Throttling Mode: Meter-in Control (supply throttling)

• Component Series: 30 (belongs to 3X series)

• Design Code: B

Key Technical Advantages

1. Sandwich Plate Design for Compact Integration

The Z2FS22 series features a sandwich plate design that mounts directly between the directional valve and subplate. This eliminates additional piping, significantly simplifying hydraulic system layout, reducing potential leak points, and saving installation space.

2. Symmetrically Arranged Dual Throttle Check Valves for Independent Adjustment

Two independently arranged throttle check valves are symmetrically positioned within the valve. Each throttle check valve can be adjusted independently—limiting flow in one direction while allowing free return flow through the check valve in the opposite direction. This design enables independent speed control of the actuator in both directions.

3. Flexible Meter-in and Meter-out Control Options

Depending on the suffix “S” (meter-in) or “S2” (meter-out) , the throttling effect can be applied to either the supply or return flow. Meter-in control is suitable for controlling actuator extension speed, while meter-out control is ideal for controlling retraction speed or preventing overrunning load conditions.

4. Precision Throttle Adjustment with Stable Performance

The throttling spool is axially adjusted via a hexagon socket setting screw to vary the throttle opening. Pressure fluid within the port is applied to the spring-loaded side of the throttling spool via a channel—the applied pressure, in addition to the spring force, holds the throttling spool in the throttle position. Pressure fluid returning from the actuator moves the throttling spool, permitting free flow via the check valve function.

5. 350 bar High Pressure and 360 L/min High Flow Capacity

Delivers 350 bar maximum operating pressure and 360 L/min maximum flow in a compact NG25 package. This performance places it at the forefront of sandwich throttle check valves in its class, meeting the precision flow control requirements of diverse medium-to-high pressure, high-flow hydraulic systems.

6. International Standard Compliance for Global Interchangeability

Mounting conforms to DIN 24340 Form A, ISO 4401, and CETOP-RP 121H international standards. Fully compatible with globally adopted sandwich valve interfaces for direct replacement of same-series, same-specification products. NBR (standard) and FKM (V suffix) seal options accommodate mineral oils and phosphate ester fluids.

Application Areas

• Injection Molding Machinery — Precision adjustment of injection speed and clamping speed

• Hydraulic Presses and Forging Equipment — Independent speed control of slide advance and return

• CNC Machine Tools — Flow control for feed speed and rapid traverse

• Die-Casting Machines — Adjustment of injection speed and clamping speed

• Construction Machinery — Speed control for boom lift and bucket tilt functions

• Material Testing Machines — Precise adjustment of loading and unloading speeds

• Metallurgical Equipment — Flow control for rolling mill hydraulic systems

• General Industrial Hydraulic Systems — Various actuator speed control applications

Expert Maintenance Tips

1. Installation Guidelines

• Z2FS22 series mounting must conform to DIN 24340 Form A / ISO 4401 / CETOP-RP 121H standards.

• This valve features sandwich plate design—install between the directional valve and subplate. Pay attention to sealing and bolt length between stacked valve layers.

• Thoroughly clean the mounting surface and all ports before installation to prevent foreign particles from entering and causing throttling spool sticking or seal damage.

• Z2FS22 corresponds to NG25 nominal size—ensure subplate and directional valve port sizes match.

2. Throttling Mode Selection

• S type (meter-in) : Throttling occurs in the supply flow—suitable for controlling actuator extension speed.

• S2 type (meter-out) : Throttling occurs in the return flow—suitable for controlling actuator retraction speed or preventing overrunning load conditions.

• Select the appropriate throttling mode based on actuator operating requirements.

3. Hydraulic Fluid Cleanliness

• Recommended fluids: Mineral oils per DIN 51524 (HL, HLP, HLPD, HVLP, HVLPD).

• Install a return line filter with minimum 10 μm filtration rating to ensure fluid entering the valve meets cleanliness requirements.

4. Seal Material Selection

• Standard models feature NBR seals, suitable for mineral oils.

• V suffix models (e.g., Z2FS22-3X/S2V) feature FKM seals, suitable for phosphate ester and other specialty hydraulic fluids.

• Select the appropriate seal material based on the actual hydraulic fluid used.

5. Adjustment and Maintenance

• Throttle adjustment is performed via the hexagon socket setting screw. Rotate slowly and gradually to achieve the desired flow rate.

• Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.

• If throttling response changes or instability is observed, first check system fluid cleanliness and verify the throttling spool is not sticking or worn.