HBH Series Redundant Hydraulic Block & Stop Safety Valve Systems Operating Instructions (RC-HBH-OI)

Overview

The ROSS Controls HBH Series provides redundant hydraulic block and stop safety valve systems designed to allow or block hydraulic fluid flow in both directions between a directional control valve and its associated cylinder. When activated, the HBH system blocks flow to stop cylinder motion — a "Block & Stop" rather than "Block & Bleed" function.

The HBH Series is designed to meet Category 3, PL d / SIL 2 per ISO 13849-1:2015 and IEC 62061:2001 when properly implemented in a safety control and monitoring system. SIL 3 certification is also achievable with proper implementation. The system is intended as a "permissive" safety device — it uses spool-type valves, and normal spool leakage will occur. For applications requiring long-term holding, supplemental PO check valves, counterbalance valves, or mechanical locking devices should be incorporated.

Available in Body Sizes 25 and 32, with flow rates of 0–90 gpm and 0–145 gpm respectively, the HBH Series accommodates large hydraulic systems. ROSS Controls, founded in 1921, brings over 100 years of fluid power engineering expertise to hydraulic safety applications. Contact ROSS at 1-800-GET-ROSS or visit www.rosscontrols.com.

Key Features

Block & Stop Function for Bidirectional Flow Control

Unlike block-and-bleed systems, the HBH Block & Stop function closes both the A and B ports to stop cylinder motion in either direction without bleeding downstream energy. This allows the HBH to be used as a permissive safety device that stops motion when required, rather than always bleeding downstream pressure. This is suited to applications where the actuator needs to stop in place momentarily rather than requiring full pressure relief.

High-Flow Redundant Valve Design

Body Sizes 25 and 32 provide flow capacities of 0–90 gpm and 0–145 gpm, accommodating large hydraulic presses, heavy machinery, and other high-flow hydraulic systems. Code 62 flanged ports are provided for both sizes, with port sizes of 1-1/2 inch (682F), 2 inch (692F), and 2 inch (792F).

Inductive Position Switches for Monitoring

Two inductive position switches per system provide spool position feedback to the external safety monitoring system. Switch connector pinout: Pin 1 — +24 VDC supply; Pin 2 — Output Signal NC; Pin 3 — Ground; Pin 4 — Output Signal NO. PNP position switches can be wired as NO or NC by the consumer.

External Monitoring for Flexible Safety Integration

The HBH Series uses external monitoring, allowing it to interface with a variety of safety PLCs, safety relays, and machine control systems. This flexibility enables integration into both new machine designs and retrofit safety upgrades.

Technical Specifications

Specifications from HBH Series operating instructions (RC-HBH-OI):

Safety Category: Cat. 3, PL d per ISO 13849-1:2015 (SIL 3 with proper implementation)
Safety Integrity Level: SIL 3 per IEC 62061:2001
Certification: Pending (per operating instructions)
Standard Voltage: 24 volts DC
Power Consumption: 30 watts per solenoid
Inductive Position Switches: 2 per system
Flow Capacity — Body Size 25: 0 to 90 gpm; 1-1/2 inch Code 62 flange ports (682F)
Flow Capacity — Body Size 32: 0 to 145 gpm; 2 inch Code 62 flange ports (692F or 792F)
Seal Type: Buna-N
Valve Type: Spool-type, double (redundant)
Monitoring: External
Communication: None (standard)
Pressure Relief: No Pressure Relief Valve (standard)
Mounting: Any orientation, preferably horizontal

Applications

Large Hydraulic Press and Machine Safety Stop Functions

The HBH Series is suited to large hydraulic presses and industrial machinery requiring a high-flow redundant block-and-stop safety function. Applications include hydraulic stamping presses, forming presses, and heavy industrial actuator systems where stopping cylinder motion — rather than bleeding downstream pressure — is the required safety function.

Permissive Safety Device in Complex Hydraulic Circuits

As a permissive safety device, the HBH Series is used in safety circuits where the valve permits or blocks motion based on safety system state. When the safety condition is met, the HBH allows flow; when a safety violation is detected, the HBH blocks flow in both directions to stop the actuator. The spool-type design allows high flow rates with low pressure drop in the permissive state.

Safety and Compliance Standards

ISO 13849-1:2015 — Category 3, PL d
IEC 62061:2001 — SIL 3 (with proper implementation)
Machinery Directive 2006/42/EC — Declaration of Conformity
ROSS intended use: momentary stopping of actuators, not long-term holding

Installation and Setup Guide

Mounting and Flange Connections

Mount the HBH preferably in a horizontal orientation; any orientation is acceptable. Connect hydraulic lines to Code 62 flanged ports per the port identification on the valve body. Ensure hydraulic fluid is clean and compatible with Buna-N seals.

Inductive Switch Wiring

Wire both inductive position switches to the external safety monitoring system. Pin 1: +24 VDC; Pin 2: NC output; Pin 3: Ground; Pin 4: NO output. The monitoring system must respond to unexpected spool positions by inhibiting machine operation.

Important Limitations

Block and Stop functions are intended to momentarily stop an actuator, not to hold it in place for an extended period. Normal spool leakage will occur. For applications requiring long-term holding, incorporate PO check valves, counterbalance valves, or mechanical locking devices in addition to the HBH system.

Why Choose ROSS Controls

ROSS Controls has over 100 years of fluid power expertise since 1921. The HBH Series reflects ROSS's commitment to extending proven redundant valve technology to hydraulic safety applications. ROSS offers a complete hydraulic safety valve portfolio including the HBB (block and bleed), HBH (block and stop), HDBH (dual block and stop), and H L-O-X® (hydraulic lockout) series. Contact ROSS at 1-800-GET-ROSS or visit www.rosscontrols.com.

Download This Document

The official HBH Series Operating Instructions (RC-HBH-OI) are available as a free PDF download from ROSS Controls.

PDF Download URL: https://ross-admin-global-us-east.s3.amazonaws.com/production/uploads/document_language_file/file/205/ROSS_Hydraulic_Block-and-Stop_HBH_Series_Operating_Instructions_RC-HBH-OI_en.pdf

Frequently Asked Questions

Q: What is the difference between block and stop vs. block and bleed?

A: Block and Bleed (HBB Series) simultaneously blocks supply flow and bleeds downstream energy to tank. Block and Stop (HBH Series) blocks flow in both directions to stop cylinder motion, but does not actively bleed downstream pressure. The HBH is a "permissive" device that stops motion rather than relieving pressure.

Q: What safety category does the HBH Series achieve?

A: Category 3, PL d per ISO 13849-1:2015. SIL 3 per IEC 62061:2001 is achievable with proper implementation.

Q: What are the available flow rates?

A: Body Size 25: 0–90 gpm with 1-1/2 inch Code 62 flanged ports. Body Size 32: 0–145 gpm with 2 inch Code 62 flanged ports.

Q: Can the HBH hold an actuator in position for an extended period?

A: No. The HBH uses spool-type valves and normal spool leakage will occur. For long-term holding, incorporate PO check valves, counterbalance valves, or mechanical locking devices alongside the HBH.

Q: What is the standard operating voltage?

A: 24 volts DC. Power consumption is 30 watts per solenoid.

Q: What hydraulic fluids are compatible?

A: Compatible with mineral oil and vegetable oil hydraulic fluids compatible with Buna-N seals. Consult ROSS for specific fluid compatibility questions.

Q: How are the inductive position switches wired?

A: Pin 1: +24 VDC supply; Pin 2: Output Signal NC; Pin 3: Ground; Pin 4: Output Signal NO. PNP switches can be configured by the user as NO or NC.

Q: What mounting orientation is recommended?

A: Horizontal orientation is preferred, but any orientation is acceptable.

Q: Does the HBH include a pressure relief valve?

A: Standard HBH configuration has no pressure relief valve. Consult ROSS for options.