CN2400605Y - Damped suction valve for displacement pump - Google Patents

Abstract

The utility model relates to a damped suction valve for a displacement pump, which is characterized in that a valve cover 1 provided with a solid body extends to the position of a guide housing 4 and is in contact with the guide housing 4. A cavity 3 is formed between the inner surface of a valve core, the valve cover and the guide housing. An orifice, which can make the liquid circulate, is arranged on part of the valve cover where the cavity is in contact with the solid body. Because the throttling effect can generate hydraulic loss, the pressure in the cavity and the suction pressure of primary liquid is unequal when the liquid flows across the orifice with high speed in the process of opening and closing of the valve core. Consequently, a force opposite to the direction of motion of the valve core is generated, and the force is the damping force. The utility model reduces the impact force of the valve core and alleviates the abrasion of the valve core to a valve seat, the valve cover, etc. So the valve has the advantages of less abrasion, low noise and long service life.

Description

Reciprocating pump damped type suction valve

The utility model relates to a kind of valve, the suction valve of using on especially a kind of reciprocating pump.

Suction valve is the easily worn part of reciprocating pump.Existing reciprocating pump opens and closes suction valve with the motion of spool between valve gap and valve seat of suction valve in a short period of time, its moving element spool produces very big striking velocity and impact force, parts such as bump valve seat, valve gap and it is caused than galling, and near the noise the pump housing is higher usually, reaches more than 85 decibels.So the working life of ordinary circumstance low suction valve is all lower.For working life that prolongs suction valve and the using scope of expanding reciprocating machine, the general now method that adopts the mechanical property of materials (pile-up welding hard alloy, spraying wear-resistant materials are heat-treated etc.) of contact components (friction pair) such as improving valve seat, valve gap.Obviously, these methods are passive.

The purpose of this utility model is to overcome above-mentioned deficiency, and provide a kind of wear and tear little, noise is low, the reciprocating pump of long service life damped type suction valve.

The purpose of this utility model realizes by following technical solution: a kind of reciprocating pump damped type suction valve, comprise valve gap, spring, guide housing, spool, valve seat, the valve gap that it is characterized in that the tool solid body extends to the guide housing place, and contact with guide housing, between the internal surface of spool and described valve gap, guide housing, forming a cavity, and with that part of valve gap of the contacted solid body of described cavity in a throttle orifice that can make liquid communication is arranged.

The utility model utilizes fluid mechanics principle, when spool is opening or closing in the process, when liquid at high speed is flowed through throttle orifice, because throttle effect will produce hydraulic loss, making described cavity internal pressure and primary liquid suction pressure unequal, is damping force thereby produce a power opposite with the valve core movement direction.This damping force can make spool produce negative acceleration in the second half that opens or closes, and has reduced striking velocity and impact force when spool opens or closes, has alleviated the wearing and tearing to parts such as valve seat, valve gaps.Therefore, this suction valve have wearing and tearing little, noise is low, the advantage of long service life.And this damping force can disappear after valve wide open or full cut-off automatically, does not influence the normal operation of this valve and reciprocating pump.

Below in conjunction with drawings and Examples the utility model is described in further detail.

Fig. 1 is structural representation of the present utility model and opening procedure working principle schematic representation.

Fig. 2 is structural representation of the present utility model and closes closed procedure working principle schematic representation.

Fig. 3 is structural representation and the opening procedure working principle schematic representation of known reciprocating pump with suction valve.

With reference to Fig. 1 as can be known: the utility model reciprocating pump damped type suction valve is made of valve gap 1, spring 2, guide housing 4, spool 5, valve seat 6.Known reciprocating pump is with having an opening 8 between the valve gap 1 of suction valve and the guide housing 4, makes a part of liquid circulate from this opening 8 (referring to Fig. 3).The utility model is that the valve gap 1 with the tool solid body extends to guide housing 4 places, and contact with guide housing 4 and (perhaps the valve gap 1 of guide housing 4 to the tool solid body to be extended, and contact) with it, seal above-mentioned opening 8, between the internal surface of spool 5 and described valve gap, guide housing, forming a cavity 3, and with that part of valve gap of described cavity 3 contacted solid bodys in a throttle orifice 7 (shape of throttle orifice is arbitrarily) that can make liquid communication is arranged.Like this, a part of liquid will circulate from throttle orifice 7.Certainly, also can with that part of guide housing of described cavity 3 contacted solid bodys in offer a throttle orifice that can make liquid communication, electric energy reaches same effect.

In the process that spool is opened, the flow direction of liquid is shown in Fig. 1 arrow X, and the moving element spool carries out the straight line motion of direction shown in Fig. 1 arrow Y.Its suffered power has: (A) lift; Because liquid is when flowing through the slit of spool and valve seat, change has taken place in the size and Orientation of speed, and having theorem of momentum to know will produce a lift to spool; (B) spring force; (C) gravity; (D) inertial force.Under the effect of these four power, spool will move to the valve gap direction with bigger acceleration.By continuous motion equation and Bernoulli's equation, when the liquid at high speed in the described cavity 3 is flowed through throttle orifice,, make the pressure P 3 of cavity 3 be higher than suction pressure P because throttle effect will produce hydraulic loss _s, producing a power opposite with the valve core movement direction thus is damping force.Below analyze by mathematical expression.Because the loss that throttle effect produces (comprise the local hydraulic loss and, wherein be directly proportional with the length L of throttle orifice) along the journey hydraulic loss along the journey hydraulic loss, the pressure P 3 and the suction pressure P of cavity 3 _sPressure differential deltap P and spool speed have following relationship:

Δ P=P ₃-P _s=(∑ ξ) V ², ξ is resistance coefficient (relevant with the length L of throttle orifice), V is the speed of flow of liquid when throttle orifice.

Can obtain by the continuous-flow equation:

, V _pBe the movement velocity of spool, d _kBe the equivalent hydraulic diameter of throttle orifice, D _pBe the diameter of stress surface, n is the number of throttle orifice.

Have thus: $\mathrm{\ΔP}=\mathrm{\Σ}\left(\mathrm{\ξ}\right){\left(\frac{D_p}{d_k}\right)}^4{\left(\frac{1}{n}\right)}^2{V}_p^2-------\left(1\right)$

Formula (1) shows, the pressure P 3 and the suction pressure P of cavity 3 _sThe pressure differential deltap P and equivalent hydraulic diameter, the number of throttle orifice, the throttle orifice length of throttle orifice relevant, and and square being directly proportional of valve core movement speed.Work as d _kValue more hour, the pressure P 3 of cavity is big more, with suction pressure P _sPressure differential deltap P big more, the damping force of generation is also just big more.Work as V _p, D _pWhen remaining unchanged, can be fully possible by adjusting diameter, number and the length of throttle orifice, producing suitable damping force.When spool arrived fully open position, its movement velocity was 0, and pressure differential deltap P also just is 0, so damping force disappears, did not influence the normal operation of this valve and reciprocating pump.

Close (spool is to the motion of valve seat direction) in the closed procedure at spool, the form of its working principle and various power and opening procedure all fours, and the pressure in the cavity is less than suction pressure, the direction of its damping force and lift is opposite with opening procedure, concrete condition can just illustrate here no longer one by one referring to Fig. 2.Again according to Newton's laws of motion: $m_p\frac{{\mathrm{dV}}_p}{\mathrm{dt}}=F_h-\mathrm{\Δ}{\mathrm{PA}}_{\mathrm{pv}}-F_s-m_{p}g-----\left(2\right)$

F in the formula (2) _hBe the lift that fluid flows and produces, F _sBe spring force, m _pBe the quality of spool, A _PvBe compression area.

Choose various geometric combination, can find the solution equation (2), try to achieve the speed of maximum displacement of spool arrival valve gap and the closing velocity when falling back to valve seat, control impact force and noise with quadravalence Rounge-Kutta numerical method.

In sum, adopt the utility model can alleviate the wearing and tearing of spool, thereby reduced noise, prolonged the working life of this suction valve, improved the reliability of reciprocating machine parts such as valve seat, valve gaps.Can also improve the volumetric efficiency of pump by the time that Regulation spring power shortens valve closing.

Claims (1)

1, a kind of reciprocating pump damped type suction valve, comprise valve gap (1), spring (2), guide housing (4), spool (5), valve seat (6), it is characterized in that: the valve gap of tool solid body (1) extends to guide housing (4) and locates, and contact with guide housing (4), between the internal surface of spool (5) and described valve gap (1), guide housing (4), forming a cavity (3), and with that part of valve gap of the contacted solid body of described cavity (3) in a throttle orifice (7) that can make liquid communication is arranged.

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