IDENTIFICATION

The BLB directional valves are labelled as follows:

Monoblock valves

These valves are supplied ready to be installed and carry just one product label:

Sectional valves

  • These valves are supplied in the following configurations:
    • Sections delivered assembled as one sole valve: these valves are ready for the installation and carry just one product label.
    • Single modular work sections delivered complete with detached accessory parts for the final assembling
      (elements, inlets and outlets, tie rods, valves, etc.). Work sections, inlets and outlets are identified by their own label.
  • The following routes have to be differentiated:
    • The final assembling is carried out by end user. No need to put further labels.
    • The final assembling is made by a third party (autorized centers by BLB) who will apply the final product identification label..

Code and part number

The product code is made of seven digits. The first number is a “9” for all monoblock valves and for the sectional
valves supplied as a sole unit; the first number is a “8” for loose sections.
Part number is made of seven numbers (progressive number) and a letter (month) and two digits (year) of
manufacturing.


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GOODS RECEIPT AND STORAGE

Preventive inspection

On receipt of delivery check that:
• Goods delivered comply with the issued order;
• Accompanying documents are complete and exhaustive, particulary when delivery differs from the original order;
• Products have not been damaged during the transport.
In case of non conformity or damages, inform BLB within eight days from receipt date.

Storage

Valves are delivered packed up in boxes. Handle with care and use means adequate to the size and weight of the boxes. Components are contained in oil proof wrappers. The internal cavities contain some remaining oil retained by the thread plastic plugs. Remove the protection plugs only when connecting the pipes. Valves present sharp edges; use protection gloves when handling them.


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DESCRIPTION

The function of the directional control valves is to direct the circulating oil flow of the hydraulic system to the use that

has been chosen by the operator (Directional drawer valve). This function is obtained by shifting the spool (drawer) inside a cavity that has regular and serial openings. The resulting connections of above openings form the requested functional circuits.
The displacement of the spool is obtained by means of actuarors. They can either be direct (manual) or indirect (electric, pneumatic, hydraulic, cable operated, etc.). The position control can be active (automatic return) or blocked in different kinds of function. In all kinds of construction, BLB directional control valves are predisposed to comply with all those essential and important functions that make hydraulic systems safe and efficient.
These main functions are:

  • Pressure setting and control (relief valve, antishock valve).
  • Oil flow control (integrated with 3-way compensated valves).
  • Non return function or block of the use.
  • Filling up function (anticavitation).
  • Indipendent feeding and usage of two circuits (or parts of them) at the same time.
  • Building circuits in parallel, series and mixed.
  • Connection with other valves using one sole source of energy.
  • Regulation of the energy by directly acting on the source.
  • Possibility of using more sources of energy.

Typologies

BLB directional control valves are divided in two main groups:

  • BM, monoblock valves, characterized by having all the above listed functions in one casting, also for more uses.
  • BC, sectional valves, characterized by having the above listed functions in one housing for each use (elements, work section).The elements can be assembled together in a quantity that is equivalent to the required uses. The setup is more flexible and therefore can easily be suitable for complex requirements.

Functional characteristics

All BLB valves are designed in 6/3, 6/4 system. The drawer controls six ways in three or four positions indistinctly. Anyway, it is possible to realize circuits with drawers type 6/2, 5/4, 5/3, 5/2, 4/3, 4/2.
The stroke of the spool, characterized by negative covering, takes place in 3 phases:

  1. Tightness covering.
  2. Progressive regulation.
  3. Complete open.

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TECHNICAL CHARACTERISTICS

Technical characteristics are deeply explained in the first part of the catalogue. We hereby only report a summary and some additional points.

Recapitulation of technical characteristics

  • Nominal flow and limits.
  • Max pressure and setting field of the main relif valve.
  • Max pressure on ports and in tank-line.
  • Connections and covering of the spool.
  • Pressure drop.
  • Threads on the ports for tube connections.
  • Spool actuations and controls.
  • Circuits and standard connections.
  • Standard accessory applications.
  • Additional functions on work sections or general functions for the whole valve.
  • Size and weight.

Materials and protections

Valves bodies are realized in cast iron and the spool in hardened steel. O-ring seals are made of synthetic rubber with oil resistant nitrilic mix, that is suitable to the mineral oil used in the hydraulic systems. Differents fluids and heavy duty conditions require seals in fluoridated elastomer mix (Viton®).
Protective treatments on the bodies are available for valves that will be exposed to aggressive enviroments.

Special characteristics

For technical specifiations that cannot be found in the catalogue, or deriving from customized applications, ask the technical service of BLB srl.

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CHOICE AND USE

Choice

The choice of the directional control valves has to respect:

  • The technical characteristics of the system (pressure, flow, temperature, maintenance). Use BLB valves within the duty limits indicated in part one of the catalogue and under respect of the operating conditions as indicated in the table 5.2.1.
  • The functional characteristics of the system and of each single work section (schematic of the hydraulic system and in particular of the valve).
  • The interfacing with the order parts of the system

Use

HYDRAULIC FLUID OIL MINERAL ACCORDING TO DIN 51524
VISCOSITY VISCOSITY RANGE 10…460 mm2/sec
OPTIMAL VISCOSITY 12…75 mm2/sec
TEMPERATURE FLUID RANGE TEMPERATURE -20 … +85 °C
SUGGESTED RANGE +30 … +60 °C
MAXIMUM CONTAMINATION LEVEL NAS 1638: CLASS 9 – ISO 4406: 19/16
ROOM TEMPERATURE -30 … +60 °C
PRESSURE AND FLOW SEE CATALOGUE
PRESSURE DROP SEE CATALOGUE
OIL VELOCITY IN THE TUBE: INLET AND PORTS 6 ÷ 8 m/sec
OIL VELOCITY IN THE TUBE: RETURN 3 ÷ 4 m/sec

 

Monoblock/Sectional

Use monoblock valves when following features are required:

  • Strong construction.
  • Reduced size and weight.
  • Simple circuits.
  • Higher reliability and less maintenance (no tie rods interface O-rings seals).
  • Economy of the system.

Use sectional valves when following features are required:

  • Composition of the circuit very flexible and easy to modify.
  • Non return valve on each work section (contemporaneous use of more sections).
  • Possibility for the end user or the authorized third party to assembly the valve themselves.
  • Auxiliary valves on each section.

Not allowed utilizations

  • Never use directional control valve to hold actuators in a fixed position for periods of time not consistent with the work pressure.
  • Never use directional control valves in system with no filtration. The admitted contamination level is reached by using filters with 30 μm medium pores.
  • Never use directional control valves for other fluids than those reported in the enclosed chart.
  • For any use that does not come into the operating duty or functional conditions of this catalogue, ask BLB technical service and require written specifications.

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CONDITIONS OF USE

Intalling operations

Location – It is recommended to predispose the area where the valve will be placed, in order to ease the mounting, the pipe connection and the settings for start and testing.

Installation

  • When handling the valves avoid collisions and shocks.
  • Valves have to be fastened with screws through the holes made in the support zone. The mounting position is not relevant, whereas the elements forming the support must create a flat surface. This is necessary in order to avoid that the fastening causes any dangerous defarmation.
  • If is not possibile to have an adequate support, use supplementary clamps or elastic elements to eliminate geometric defects. • Install the valve in a shock and vibration proof zone.
  • Protect from oxidation with a rust-proof coating o painting. Prevent solvents for the preparing of the surface to get in contact with the mobile parts of the valve.
  • Screws, fittings and pipes must be tightened by means of proper torques and adequate keys, better with torque control (dinamometric keys). Never use fictitious extensions and never push on torque. An extreme tightening might cause deformations of the valve and compromise its regular performance.

Pipe connection (ingresso, utilizzi, scarico)

  • Remove protection plugs from ports only when connecting the pipes.
  • Always use pipes and fittings suitable to the setting pressure and to the maximun flow of the system.
  • Never use tapered fittings.
  • Never use tape winded on thereads to get tightness.
  • Do not invert the connection of inlet and outlet.

Actuators and controls
Any supplementary part applied to the valve by the user to get customized actuators or spool controls should allow:

  • To perform the whole stroke of work.
  • Not to transmit such actions as to compromise the duration and the functionality of the original parts. Please note: before making any customized application, ask BLB to get its approval and, if that is the case, the preparation of the valve.

Starting

Before starting, it is a good rule to “wash the system” with oil fluxing from an auxilary plant.
  • Actuators should not be under load while starting; operate slowly untill the system is filled up.
  • Set the relief valves and make a complete testing of the system.
  • If the initial fluxing has not been made, at the end of the test, clean the filter.
  • Set the relief valve only after having mounted a manometer on line.

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MAITENANCE

Normal maintenance

  • Periodically, lubricate the mobile parts located in the manual actuators and in the controls.
  • Periodically, check the functioning of the relief valve.
  • Periodically, clean the filter of the system. Excess of contamination of oil causes misfunctions of the spool and relief valve.

Preventive maintenance

  • Replace filter every time the system oil is changed.
  • Check the setting of the relief valve, and replace it when it is no longer reliable.
  • In sectional valves, check the tightening of tie rods by using a dinamometer key.

Extraordinary maintenance

In case of intervention for which to dissamble the valve is necessary, contact an authorized technicians.
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DEFECTIVITY AND DEMOLITION

Defects

Valves are delivered tested according to the conditions declared in this catalogue. Defects that may be found when first installing the valves usually depend either on the non respect of indications in chapter 5 or on damages occurred during the transport.
During the period of work, the following may be found:

Problem Causes Rimedies
Sticking of the spool Excess of work pressure.
  • Check the work pressure and the setting of the valves.
  • Eliminate the possible ram shocks (pressure peaks).
Excess of oil contamination.
  • Change oil and filters.
  • Wash the plant with an auxiliary fluxing.
  • Have more frequent maintenance
Valve does not fit the application
  • Correct the choice of the directional control valve
Additional controls and actuators.
  • Check or modify the additional applications
Excess of torque in the fastening of screws.
  • Loosen fittings and fastening screws.
Support base with serious geometric defects (not flat).
  • Use supplementary clamps or elastic elements.
Excess of working temperature.
  • Check the setting of the relief valves and reduce the pressure drop in the system.
Oil leaking between elements or in corrispondence of the spool
Causes:
Excess of working temperature.
  • Increase the quantity of oil in the system (increase the tank size).
  • Reduce the pressure drop in the plant.
  • Improve the cooling of the oil.
  • Check or modify the valve setting.
  • Replace the seals or the whole valve.
Excess of working pressure.
  • Check the work pressure and the setting of the valves.
  • Eliminate the possible ram shocks (pressure peaks).
Valve does not fit the application.
  • Correct the choice of the directional control valve
The periodical check of torque on tie rods has not been made.
  • Restore torque of the tie rods.
  • Have more frequent checks.
Worn out or broken O-ring seals on the valve.
  • Replace the O-ring seals.
Excess of flow in the valve.
  • Correct the choice of the directional control valve or the pump.
Back-pressure in the tank-line
  • Check eventual throttlings towards the tank.
Excess of internal leakage Excess of work pressure.
  • Check the work pressure and the setting of the valves.
  • Eliminate the possible ram shocks (pressure peaks).
Excess of works temperature.
  • Increase the quantity of oil in the system (increase the tank size).
  • Reduce the pressure drop in the plant.
  • Improve the cooling of the oil.
  • Check or modify the valve setting.
  • Replace the seals or the whole valve.
Valve does not fit the application.
  • Correct the choice of the directional control valve
Worn out or broken O-ring seals or the valves.
  • Replace the O-ring seals or the whole valves.

Spare parts

Replace the pieces to be changed only with original spare parts.

Demolition

No longer usable valves must be disassambled to seperate metallic parts from synthetic material or rubber.

Do not waste the single elements or the oil remeining therein.

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TRANSPORT

Handle with care whether the transport is made by single pieces, loose boxes or by pallets. Take all possible steps to avoid damages that might compromise the functional efficiency of the valves and the safety of users.

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SPECIAL PRODUCTS

BLB directional control valves are characterized by a high quantity of possible functional combinations. Specifictaions for products with high customized combinations of functions might not be found in the catalogue. For these products, BLB guarantees the necessary assistance to determine the best setting and the preparation of the documents (integrative to the catalogue) that are necessary for the installation and the correct use.

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WARRANTY AND LIMITATIONS OF LIABILITY

Premise:
BLB products are exclusively appointed to professional operators and end users. Therefore, in warranty topics, it is not applied the discipline of law by decree n. 24 of the 02/02/2002 in performance of European directive 1999/44/CE. All products are warranted for a period of 12 (twelve) months from date of shipment from BLB to be free from defects in material and workmanship under:

  • Correct use
  • Normal operating conditions
  • Proper application

Seller’s obligation under this warranty shall be limited to the repair or exchange, at seller’s option, ex-factory, of any seller’s product or part which proves to be defective as provided herein. Seller’s reserves the right to either inspect the product at Buyer’s location or require it to be returned to the factory for ispection, free of charge. Any description of goods, including any reference to Buyer’s specifications and any description in catalogues, circulars and other written material published by the seller is for the sole purpose of identifying such goods and shall not create an express warranty that the goods shall conform to the sample or model. Buyer is the sole responsible for determining the suitability of goods sold hereunder for use of buyer. Seller reserves the right to discontinue, modify or revise the specifications or the products described herein. The above warranty does not extend to goods damaged, or subjected to accident, abuse or misuse after shipment from seller’s factory, nor to goods altered or repaired by anyone other than authorized by seller’s representatives. Seller will in no event be liable for any incidental or consequential damages whatsoever, nor for any sum in excess of the price received for the goods for which liability is claimed. Equipments produced by third parties and included in the supply together with items produced by BLB are subjected to the warranty conditions of the parts producer. BLB is not subjected to warranty obligations on breakdowns, damages or inefficiencies deriving from wrong installation, intentional or unintentional tampering, bad maintenance, negligence and incapacity of the end user. Modifications or repairs made by people not expressly authorized by BLB, shall cause the warranty cancellation. Supplys delaied in payment or not paid, even partially, shall cause the warranty cancellation. Warranty conditions do not confer to the customer the right to suspend or delay the payments which will have to be made in any case under the conditions agreed and specified on written order confirmations.

BLB reserves the right of cancelling the warranty if:

  • Tags or labels with the producer mark and product code and series number have been removed
  • The product has been subjected to alterations or modifications not expressly authorized by BLB
  • The product has not been used in conformity to the instruction supplied
  • The product has been used for other purposes than those for which it has been designed Warranty is recognized only to BLB’s direct customers.

Anyone being in possession of BLB products which however have been bought through third parties (distributors, reseller, installers or manufacturers of any kind) will have to contact the direct supplier for any eventual warranty claim.

THERE ARE NO EXPRESS WARRANTIES OTHER THAN THOSE SPECIFICALLY DESCRIBED HEREIN.

  • The Court of Justice of seller’s seat (BLB S.r.l. – Vicenza – Italy) is the only competent for any controversy

GENERAL SALES CONDITIONS

General sales conditions may differ from Country to Country.
Our sales department will send all necessary information upon request. For anything not specified, will be valid the norms of the Civil Code in matter.