CN202066257U - Thermostatic expansion valve - Google Patents

Abstract

The utility model discloses a thermostatic expansion valve which comprises an air box head and a valve body. The air box head comprises a temperature sensing tube, a capillary tube, an air box cover, an air box base, a transmission plate and a diaphragm. The air box cover is communicated with the temperature sensing tube through the capillary tube; the diaphragm is arranged between the air box cover and the air box base; the transmission plate is arranged in the air box base below the diaphragm; the lower end of the air box base is connected with the valve body; and when the valve body is closed, the diaphragm bulges to the air box cover. The thermostatic expansion valve has the advantages that as diaphragm reverse motion is adopted, the operation effect of the elastic force of the diaphragm is changed into promoting the opening of the expansion valve from affecting the opening of the expansion valve in a low-temperature zone, so that the influence of the elastic force of the diaphragm, which can not be ignored, is eliminated fundamentally, and as the motion of the diaphragm is changed into reversed upward motion, the volume of the air box head is correspondingly reduced, the phenomenon of reversing control caused by a working medium in a temperature sensing bulb, which is possible to be coagulated on the air box head, is reduced, and reducing the volume of the air box head can improve the control sensibility of the temperature sensing tube under the situation that the volume of the temperature sensing tube is not changed.

Description

Heating power expansion valve

Technical field

The utility model relates to heating power expansion valve.

Background technology

Heating power expansion valve is one of indispensable four big parts (compressor, condenser, expansion valve, evaporimeter) in the freon refrigeration device (freezer, refrigerator, air-conditioning etc.), is mainly used to regulate refrigerant flow.It is the control valve of control flow, is again simultaneously the choke valve in the refrigerating plant.It is installed between liquid reservoir and the evaporimeter, and its temperature-sensitive pipe is that wrapping is at the evaporator outlet end.

The main effect of heating power expansion valve has following 3 points:

1. throttling step-down when making the refrigerant liquid of normal temperature high voltage flow through expansion valve, the cold-producing medium moist steam that becomes low-temp low-pressure enters evaporimeter, evaporation heat absorption in evaporimeter, thus reach the purpose of refrigeration cool-down.

2. the variation of the evaporator outlet refrigerant vapour degree of superheat of experiencing according to sense temperature-sensitive pipe changes the open degree of expansion valve, regulates the refrigerant flow of inflow evaporator automatically, and refrigerant flow is complementary with the thermic load of evaporimeter all the time.

3. by the control of expansion valve, make the refrigerant vapour of evaporator outlet keep certain degree of superheat, can guarantee the making full use of of heat transfer area of evaporimeter, can prevent that again compressor from liquid hammer occurring towards the cylinder phenomenon.

Heating power expansion valve is mainly by air tank head parts 1, valve body 2, spool 3, drive link 4, regulating spring 5 parts such as grade are formed, its structure diagram as shown in Figure 1, and the air tank head parts mainly play temperature-sensitive, transfer function, it is by temperature-sensitive pipe 6, capillary 7, gas tank lid 8, diaphragm 9, gas tank seat 10, driver blade 11 parts such as grade are formed, wherein diaphragm is divided into two chambeies up and down with whole air tank head parts, epicoele is a closed container, filling an amount of refrigeration working medium in the temperature-sensitive pipe (is many to fill with worker quality liquid generally, other has the liquid cross charge, gas charge, mix and fill, absorptive charge etc., mainly require to decide according to systematic function), its pressure inside P _FullChange with temperature-sensitive pipe variation of temperature; Cavity of resorption communicates with the evaporimeter of system, pressure and evaporating pressure P _OConsistent.Its structure diagram such as Fig. 2, shown in Figure 3.

According to the operation principle of heating power expansion valve, the diaphragm of air tank head is carried out force analysis, as Fig. 4, P _O-evaporating pressure.Its size is determined by evaporating temperature.P _BulletThe pressure that-spring force is converted to.Its size is determined by spring controlled degree of tightness.P _Full-charge into the saturation pressure of working medium in the temperature-sensitive bag.Its size is by the height decision of the character of working medium in the temperature-sensitive bag and the evaporator outlet place refrigerant temperature experienced.P _KThe inlet and outlet pressure difference of-expansion valve the power on the spool of acting on is converted to the pressure to diaphragm.It is relevant with the valve port size, and pressure is generally minimum, and it is also minimum to the work influence of expansion valve, almost can ignore.P _FilmThe pressure that-diaphragm elastic force is converted to.The pressure loss of diaphragm itself just, it increases the work influence of the expansion valve reduction with evaporating temperature.It acts on the diaphragm below.Act on the diaphragm below 3 pressure: P are arranged _O, P _BulletAnd P _Film, these three power are closed valve; And above acting on diaphragm 2 saturated P of pressure: P are arranged _K, these two power are opened valve; Work as P _Full+ P _K=P _O+ P _Bullet+ P _FilmThe time, valve is in the poised state of a certain aperture.

When the thermic load of evaporimeter increases, cause that the degree of superheat of evaporator outlet place cold-producing medium increases, the temperature experienced of temperature-sensitive bag raises so, its corresponding saturation pressure P _FullAlso increase, form P _Full+ P _K＞P _O+ P _Bullet+ P _FilmSo just cause diaphragm to promote drive link and move down, the aperture of valve is increased, refrigerant flow increases, and refrigerating capacity increases, thereby is complementary with the thermic load of evaporimeter.At this moment valve is in a new poised state again.

On the contrary, when the thermic load of evaporimeter reduces, cause that the degree of superheat of evaporator outlet place cold-producing medium reduces, the temperature experienced of temperature-sensitive bag reduces so, its corresponding saturation pressure P _FullAlso reduce, form P _Full+ P _K＜P _O+ P _Bullet+ P _FilmSo just cause spring to promote to move on the drive link, the aperture of valve is reduced, refrigerant flow reduces, and refrigerating capacity reduces, thereby is complementary with the thermic load of evaporimeter.At this moment valve is in another new poised state again.

So heating power expansion valve is an aperture of adjusting valve according to the variation of the refrigerant superheat degree of evaporator outlet, the cold that reaches automatic adjusting refrigerating plant is to satisfy the demand that extraneous thermic load constantly changes.

Heating power expansion valve in the market mainly has the following disadvantages:

1. along with the reduction of evaporating temperature, the degree of superheat of opening expansion valve increases, and makes that the temperature controlling range of expansion valve is less, is not suitable for working at low temperatures;

2. the actual effective area of diaphragm less (be generally design area 40%～60%), the unlatching sensitivity of expansion valve is lower, causes the corresponding increase of the unlatching degree of superheat of expansion valve, causes the action of expansion valve to lag behind, cause the fluctuation of evaporimeter thermic load, influence refrigeration.

The utility model content

The purpose of this utility model is to provide heating power expansion valve, can effectively solve existing heating power expansion valve temperature controlling range little, be not suitable for low-temperature working, open the lower problem of sensitivity.

In order to solve the problems of the technologies described above, the utility model is achieved through the following technical solutions: heating power expansion valve, comprise air tank head and valve body, described air tank head comprises temperature-sensitive pipe, capillary, gas tank lid, gas tank seat, driver blade, diaphragm, described gas tank lid communicates with the temperature-sensitive pipe by capillary, described diaphragm arrangement is between gas tank lid and gas tank seat, described driver blade is arranged in the gas tank seat of diaphragm below, the lower end of described gas tank seat links to each other with valve body, when valve body was closed, diaphragm was to gas tank lid projection.

Preferably, when valve body was opened to maximum position, diaphragm was in level; Guarantee the indeformable stroke that presses down that obtains maximum simultaneously of diaphragm.

Preferably, described gas tank tops has through hole, and described capillary one end is connected with through hole, and the described other end capillaceous is connected with the temperature-sensitive pipe; Guarantee that the pressure in the temperature-sensitive pipe in time conducts.

Compared with prior art, the utility model has the advantages that: the principle that has changed the diaphragm positive action of traditional heating power expansion valve, adopted the principle of diaphragm counteragent, make diaphragm elastic force change the unlatching that promotes expansion valve into from the unlatching that influences expansion valve in the work effect of low-temperature space, fundamentally eliminated the elastic force influence that diaphragm self be can not ignore, because the action of diaphragm changes oppositely upwards design into, correspondingly reduced the volume of air tank head, reduced working medium in the temperature-sensitive bag may condense in too much on the air tank head and caused that " control reverses " phenomenon, under the situation of the constancy of volume of temperature-sensitive pipe, reduce the sensitivity that the volume of air tank head can improve temperature-sensitive management and control system.

Description of drawings

Fig. 1 is the structural representation of existing heating power expansion valve;

Fig. 2 is the structural representation of air tank head in the existing heating power expansion valve;

Fig. 3 is the structural representation of diaphragm arrangement in the existing heating power expansion valve;

Fig. 4 is the stressed schematic diagram of diaphragm in the existing heating power expansion valve;

Fig. 5 is the structural representation of diaphragm arrangement in the utility model heating power expansion valve;

Fig. 6 is the stressed schematic diagram of diaphragm in the utility model heating power expansion valve;

Fig. 7 is the pressure-temperature curve of the utility model heating power expansion valve and existing heating power expansion valve, cold-producing medium R22.

The specific embodiment

Consult the embodiment of Fig. 5 for the utility model heating power expansion valve, heating power expansion valve, comprise air tank head and valve body, described air tank head comprises temperature-sensitive pipe 6, capillary 7, gas tank lid 8, gas tank seat 10, driver blade 11, diaphragm 9, described gas tank covers 8 tops and has through hole, described capillary 7 one ends are connected with through hole, the other end of described capillary 7 is connected with temperature-sensitive pipe 6, described diaphragm 9 is arranged between gas tank lid 8 and the gas tank seat 10, and described driver blade 11 is arranged in the gas tank seat 10 of diaphragm 9 belows, and the lower end of described gas tank seat 10 links to each other with valve body, when valve body is closed, diaphragm 9 covers 8 projectioies to gas tank, and when valve body was opened to maximum position, diaphragm 9 was in level.

Consult Fig. 6, the air tank head diaphragm operating principle after the change is just preceding opposite with change, force analysis: acting on the diaphragm below has 2 pressure: P _OAnd P _Bullet, these two power are closed valve; And above acting on diaphragm 3 pressure: P are arranged _Full, P _FilmAnd P _K, these three power are opened valve; Work as P _Full+ P _Film+ P _K=P _O+ P _Bullet, i.e. P _Full+ P _K=P _O+ P _Bullet-P _FilmThe time, valve is in the poised state of a certain aperture.With comparing before the change (is P _Full+ P _K=P _O+ P _Bullet+ P _Film), be not difficult to find out that under same operating mode, opening the required degree of superheat of expansion valve equally (is corresponding bulb pressure P _Full), after the change than the change before little 2 times P _Film, this just greatly reduces the degree of superheat that expansion valve is opened at low temperatures, even under limiting temperature, expansion valve also can normally be opened.

Here, P _FilmThe pressure that-diaphragm elastic force is converted to, the pressure loss of diaphragm itself just, it acts on the diaphragm below before the change, and the unlatching of expansion valve is played inhibition, and this inhibition increases with the reduction of evaporating temperature; It acts on the diaphragm top change back, and the unlatching of expansion valve is played a driving role, and this facilitation also increases with the reduction of evaporating temperature.

Consult Fig. 7, example R22 be the unlatching curve of actual test of the heating power expansion valve of cold-producing medium, the A line is for adopting the needed temperature-sensitive pipe pressure-temperature curve of thermal expansion opening of valves of the present invention among the figure, the B line is the intrinsic saturation pressure-temperature curve of cold-producing medium R22, the C line is the required temperature-sensitive pipe pressure-temperature curve of the thermal expansion opening of valves of prior art, when evaporating temperature is 0 ℃, the unlatching degree of superheat of conventional expanded valve is: 3.9 ℃-0 ℃=3.9 ℃, and the unlatching degree of superheat of expansion valve of the present invention is :-1.5 ℃-0 ℃=-1.5 ℃, just begin to open when being lower than 1.5 ℃ of evaporating temperatures; When evaporating temperature is reduced to-30 ℃, the unlatching degree of superheat of conventional expanded valve is :-23 ℃-(30 ℃)=7 ℃, and the unlatching degree of superheat of expansion valve of the present invention is :-34.9 ℃-(30 ℃)=-4.9 ℃, just begin to open when being lower than evaporating temperature-4.9 ℃.This has just improved the unlatching performance of valve greatly, and particularly during low temperature, the conventional expanded valve is when-33 ℃ of temperature, and its opening pressure is almost 0, and valve is because of cutting out cisco unity malfunction; And the opening pressure of expansion valve of the present invention still has about 0.08MPa, makes the valve at low temperatures still can operate as normal.

Analyze the pressure x diaphragm area on the opening force of expansion valve=diaphragm top, i.e. F=P from effective diaphragm area _FullXS, and the opening force of expansion valve is exactly to overcome the required power of regulating spring, therefore, F=F bullet=P _FullXS releases and is: S=F bullet/P _Full, the F bullet is invariable under certain operating mode in the formula, and the full front of the pressure P on diaphragm top has been analyzed, when-33 ℃ of evaporating temperatures, than about the preceding little 0.08MPa of change, just increases so the effective area S of diaphragm is corresponding after the change.By the reality test relatively, with RF22-Φ 3 type heating power expansion valves is example, its diaphragm intended diameter is Φ 3.9cm, design area is 11.94cm2, real area when recording initial open be 6.00cm2 (for design area 47.4%), and the real area when recording initial the unlatching after improving be 14.57cm2 (for design area 122%), more more than increasing before improving, and exceeded design area, therefore the unlatching sensitivity of expansion valve improves bigger, the action of eliminating expansion valve lags behind, and reduces the fluctuation of evaporimeter thermic load, has greatly improved refrigeration.

In addition,, correspondingly reduced the volume of air tank head, reduced working medium in the temperature-sensitive bag and may condense in too much on the air tank head and cause that " control reverses " phenomenon because the action of diaphragm changes oppositely upwards design into.That is to say that when the temperature of air tank head was lower than the temperature-sensitive bag, the liquid working substance in the temperature-sensitive bag will be migrated on the air tank head, if the volume of air tank head surpasses temperature-sensitive and contained long-pending 1/3～1/2 o'clock, the temperature-sensitive bag is with regard to effect out of hand, and " " phenomenon, expansion valve just can't operate as normal in the control reverse in generation.Therefore, under the situation of the constancy of volume of temperature-sensitive pipe, reduce the sensitivity that the volume of air tank head can improve temperature-sensitive management and control system.This effect is being played in this design virtually.

The above only is a specific embodiment of the utility model, but technical characterictic of the present utility model is not limited thereto, any those skilled in the art is in field of the present utility model, and variation of being done or modification all are encompassed among the claim of the present utility model.

Claims (3)

1. heating power expansion valve, comprise air tank head and valve body, described air tank head comprises temperature-sensitive pipe (6), capillary (7), gas tank lid (8), gas tank seat (10), driver blade (11), diaphragm (9), described gas tank lid (8) communicates with temperature-sensitive pipe (6) by capillary (7), described diaphragm (9) is arranged between gas tank lid (8) and the gas tank seat (10), described driver blade (11) is arranged in the gas tank seat (10) of diaphragm (9) below, the lower end of described gas tank seat (10) links to each other with valve body, it is characterized in that: when valve body was closed, diaphragm (9) was to gas tank lid (8) projection.

2. heating power expansion valve as claimed in claim 1 is characterized in that: when valve body was opened to maximum position, diaphragm (9) was in level.

3. heating power expansion valve as claimed in claim 1 is characterized in that: described gas tank lid (8) top has through hole, and described capillary (7) one ends are connected with through hole, and the other end of described capillary (7) is connected with temperature-sensitive pipe (6).

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