1. Home
  2. Documentation
  3. Data sheets
  4. N°006 pilot operated pressure

  • 55,00€ inc. tax 52,13€ excl. tax

    Details
  • Promotion

    620,00€ 496,00€ inc. tax
    516,67€  413,33€ excl. tax

    Details
  • Promotion Test box for 3- and 4-wire sensor

    Test box for 3- and 4-wire sensor

    Boîtier test pour le controle des capteurs 2 & 3 fils. Capteur avec connecteur 4 broches -...

    99,00€ 89,10€ inc. tax
    82,50€  74,25€ excl. tax

  • Promotion

    3 livres pour se former en hydraulique. 55 cours associés à des vidéos consultables...

    165,00€ 148,50€ inc. tax
    156,40€  140,76€ excl. tax

    Details

Scheet N° 6

Pressure relief valve with pilot operated

  • Promo

    55,00€ 49,50€ inc. tax
    52,13€  46,92€ excl. tax

    Details
Limiteur de pression a action pilotee 1

  • La procédure de contrôle, réglage et dépannage est décrite à l'aide d'un schéma de mini-pelle 1.6T....

    55,00€ inc. tax 52,13€ excl. tax

1- Role

 

The role of the main pressure limiter is to protect the pump from overpressure.

The pump generates a flow that must be directed at all times:

  • To the hydraulic receivers.
  • To the tank using a directional valve.
  • To the tank using a pressure relief valve.

2-Composition

There are two types of pressure relief valve:

The pressure relief valve with pilot operated is composed of a pilot stage in which there is a poppet valve (item 6) with a spring of high stiffness (item 7) adjustable by the screw (item 8) and a power stage in which is found a poppet valve (item 3) provided with a jet (item 5) with a low stiffness spring (item 4) which is not adjustable.

 

3- Operation (cylinder output phase)

Limiteur de pression a ation pilotee 1

The detailed symbol (figure B) is representative of the mechanism (figure A).

The simplified symbol (figure D) makes it easier to read the diagram, but does not show the jet (item 5) to be taken into account during troubleshooting.La figure C représente le développement des surfaces A & B du clapet (rep 3).

The fixed displacement pump (item 1) driven by the engine (item 2) provides a flow rate of 50l / min at idle and 100 l / min at the working speed.

The pressure relief valve is set at 200 bar. This pressure is the addition of the hardness of the spring (item 7) 195 bar and the spring (item 3) 5 bar.

The oil from the pump moves the piston (item12) of the cylinder (item 11).

The pressure required to move the cylinder is 100 bar on the pressure gauge (item 13).

The pressure (100 bar) is established under the poppet valve (item 3), through the jet (item 5) a back pressure is returned to the poppet valve (item 3). The spring (item 4) closes the pressure relief valve.

A pressure of 100 bar also applies to the poppet valve (item 6) but the mechanical stress of the calibration spring (item 7) is greater than that of the pressure exerted on the poppet valve (item 6).

The pressure relief valve remains closed and all the flow of the pump (item 1) is directed towards the cylinder (item 12).

 

 

4- Operation (cylinder phase in mechanical stop)

Limiteur de pression a action pilotee 3

  • 55,00€ inc. tax 52,13€ excl. tax

    Details
  • Promo

    550,00€ 467,50€ inc. tax
    521,33€  443,13€ excl. tax

    Details

  • Formation hydraulique: Explication simple comprise de tous. Retrouver les cours associés aux...

    55,00€ inc. tax 52,13€ excl. tax

    Details

  • La procédure de contrôle, réglage et dépannage est décrite à l'aide d'un schéma de mini-pelle 1.6T....

    55,00€ inc. tax 52,13€ excl. tax

    Details
  • Promo

    55,00€ 49,50€ inc. tax
    52,13€  46,92€ excl. tax

    Details

The cylinder (item 12) is in mechanical stop and the pump (item 1) is driven by the motor (item 2) to the working regime.

The oil instantly accumulates in the cylinder (item 12) and the pressure rises in the circuit.

The pressure exerted under the poppet valve (item 3) is brought back against the pressure on the same poppet valve via the jet (item 5). This back pressure is limited by the opening of the poppet valve (item 6) to 195 bar. A leak calibrated by the jet (item 5) returns to the tank by the poppet valve (item 6). At this moment, the flow of the pump lifts the poppet valve (item 3) under a pressure of 200 bar (195 + 5) and returns to the tank (item 10).

It should be noted that there is a large pressure difference (ΔP) across the pressure relief valve, which causes a rapid heating of the oil.

5- Pressure relief valve adjustment with fixed displacement pump

  • Decrease the pressure relief valve.
  • Start the pump, engine working speed (max).
  • Operate a directional valve to put a cylinder in abutment.
  • Tighten the pressure relief valve by checking the setting on the pressure gauge installed at the pump outlet. If the cylinder moves, stop the adjustment and wait for the stop.

6- Adjustment range

It is imperative to make the adjustment of the pressure relief valve with engine full speed for the pump provide the maximum flow of the installation.

Pressure valves have adjustment ranges. The opening pressure varies depending on the flow through them (Figure E). These pressure differences are due to the springs of the valves and vary according to the manufacturers.

Note: The pilot operated pressure relief valve reduces the setting range compared to the direct acting pressure relief valve.

                                                                                                       

  • 55,00€ inc. tax 52,13€ excl. tax

    Details
Plage de reglage limiteur de pression a action pilotee 1

  • 55,00€ inc. tax 52,13€ excl. tax

    Details

7- Direct action or pilot operated ?

Direct acting pressure relief valve:

  • For low flows.
  • Important adjustment range.
  • Cheap.
  • Not very sensitive to oil pollution.
  • Speed of opening.

Pressure relief valve with pilot operated:

  • Decrease the size of springs for large flows.
  • Low adjustment range.
  • Sensitive to pollution.

 

  • Expertise: contrôle et réglage des pompes hydrauliquesExpertise pompe La pompe est un élément...

    0,00€ inc. tax 0,00€ excl. tax

    Details
  • Promo

    550,00€ 467,50€ inc. tax
    521,33€  443,13€ excl. tax

    Details

  • 55,00€ inc. tax 52,13€ excl. tax

    Details

Comments

  • Larquier

    1 Larquier On 08/03/2021

    Bonjour !!
    Super travail !!
    Je suis en présence sur mon schéma d'un électro distributeur 4/2 sur la branche numéro 9 pour le reste le schéma est identique au votre . En sortie de mon distributeur j'ai 2 possibilités soit un retour au tank soit un bouchon selon la commande.
    Lors que je suis sur le circuit bouchon me confirmez vous que mon limiteur de pression piloté ne fonctionnera pas.
    Merci de votre aide,
    Cordialement,
    sebhydro

    sebhydro On 08/03/2021

    Bonjour,
    Merci pour votre intérêt.
    Vous parlez certainement du distributeur de by-pass ou de "mise sous pression" souvent installé en complément du limiteur de pression à action pilotée.
    Grâce à ce distributeur, l'étage puissance (ressort de faible raideur)est décomprimé au réservoir lorsque le distributeur n'est pas actionné. Lorsque le distributeur est activé, il bouche cette fuite et rend opérationnel le limiteur de pression.
    À l'occasion, j'écrirai une fiche à ce sujet.
    sebhydro

    sebhydro On 08/03/2021

    Ici le limiteur de pression à action pillotée avec distributeur de by-pass
    https://www.sebhydro.com/pages/documentation/fiche/fiche-n-7-reglage-pompe-cylindree-variable-pression-constante-expertise-hydraulique.html

Add a comment

Anti-spam