JP4825466B2 - Constant flow valve - Google Patents

Description

  The present invention relates to a constant flow valve that is provided in the middle of a supply path that supplies gas from a storage tank that stores liquefied petroleum gas, and that supplies the gas downstream at a constant flow rate or less.

  Conventionally, when liquefied petroleum gas is supplied, a gas phase line for supplying naturally vaporized gas as it is to the combustion device, and a liquid phase line for supplying liquefied petroleum gas (liquid) by forcibly evaporating it with an evaporator, Are used in parallel (for example, Patent Document 1). And the constant flow valve is provided in the liquid phase line, It is the structure which supplies gas from a liquid phase line, restrict | limiting to the gas flow volume according to the capability of the evaporator.

In the conventional constant flow valve, an orifice is provided in the gas flow path inside the valve body, and the needle urged by the spring moves forward and backward with respect to the orifice according to the gas flow rate. While the needle moves backward from the orifice to enlarge the gas flow path, when the gas flow rate is high, the needle approaches the orifice and the gas flow path is made small, so that the gas flow rate in the liquid phase line has the rated evaporation capacity of the evaporator. It is restricted so as not to exceed.

JP 2000-121036 A

By the way, in the conventional constant flow valve, the flow rate to be limited varies due to variations in processing of each member such as an orifice, a needle, and a spring. Therefore, when designing a constant flow valve, the rated evaporation capacity of the evaporator must be constant so as not to exceed the rated evaporation capacity of the evaporator even if the restricted flow rate increases due to variations during processing. It was designed with a limited flow rate with a margin of. However, in this case, if the restricted flow rate is reduced due to variations during processing, there has been a problem that only the performance substantially lower than the rated evaporation capacity of the evaporator can be exhibited. Conventionally, in order to solve this problem, the flow rate is actually measured after the constant flow valve is assembled, and the restriction flow rate is adjusted by performing additional processing on each member such as an orifice and a spring based on the measurement result. It was. Such additional work is very laborious and costly, and has been a major problem.

The present invention has been made for the purpose of solving the above-mentioned conventional problems, and does not require any additional processing of each member constituting the constant flow valve, and is a limited flow rate that substantially matches the rated evaporation capacity of the evaporator. The present invention provides a constant flow valve capable of easily realizing the above.

In order to achieve the above object, the present invention adopts as a solution means that an orifice is provided in the main flow path of the gas inside the valve body, and is attached in a direction retreating from the orifice by a spring that acts an elastic force in the contraction direction . The urged needle is provided so as to move by a predetermined amount toward the orifice, and when the gas flow rate is small, the needle retracts from the orifice by the urging force of the spring to enlarge the gas flow path, while when the gas flow rate is large, the spring A constant flow valve that is in a fixed orifice state when the needle approaches the orifice to reduce the gas flow path against the urging force of the nozzle and the needle is positioned at the uppermost position where the needle is movable. A bypass flow path for guiding gas from the upstream side to the downstream side is formed, and a flow rate adjusting valve is provided in the bypass flow path. It lies in the fact digits.

  In this case, the flow rate adjusting valve includes a bypass valve body that advances and retreats with respect to a valve seat provided in the bypass flow path, and closes the bypass flow path when the bypass valve body contacts the valve seat. It is preferable that the valve opening gradually increases as the bypass valve element moves backward from the valve seat.

  In addition, the flow rate adjusting valve includes a rotation operation unit that advances and retracts the bypass valve body with respect to the valve seat, and changes the valve opening degree of the bypass valve body according to the rotation of the rotation operation unit. Is preferred.

  Further, it is preferable that the rotation range of the rotation operation unit is configured to be within one rotation. Furthermore, it is more preferable to attach a scale plate to the rotation operation unit.

  According to the constant flow valve of the present invention, a bypass flow path for guiding gas from the upstream side to the downstream side of the orifice is formed inside the valve body, and the flow rate adjusting valve is provided in the bypass flow path. Therefore, even if there are variations in the processing state of each member constituting the constant flow valve, when the gas flow rate passing through the orifice is insufficient, the bypass flow channel is opened and the flow rate adjustment of the gas flow flowing through the bypass flow channel is performed. By performing the above, the shortage of the gas flow rate can be compensated. Therefore, no additional processing or the like for correcting the variation in processing is required, and the necessary restricted flow rate can be easily realized.

  Further, if a rotation operation unit is provided to operate the flow rate adjustment valve and the valve opening degree of the bypass valve body changes according to the rotation of the rotation operation unit, the flow rate adjustment operation is facilitated. In particular, when the rotation range of the rotation operation unit is set to be within one rotation, the operation becomes easier. Further, by attaching a scale plate to the rotation operation unit, it becomes easy to grasp the valve opening degree, and the flow rate adjustment of the bypass flow path becomes extremely simple.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing the structure of a constant flow valve according to the present invention. In the figure, the gas flow flows from the bottom to the top. The constant flow valve is provided with a gas inlet 2 at the lower part of the valve body 1 and a gas outlet 3 at the upper part, and a gas main flow path 4 is formed therebetween. An orifice 5 is formed in the middle of the main flow path 4 so as to narrow the flow path, and a needle 6 is provided on the upstream side of the orifice 5.

  The needle 6 has a structure that becomes gradually narrower toward the tip (that is, the orifice side), and a spring holder 7 is provided at the lower end thereof. A spring 8 is connected to the spring holder 7. The spring 8 is provided to apply an elastic force in the contraction direction, and biases the needle 6 in a direction in which the needle 6 is retracted from the orifice 5 (that is, upstream of the gas flow). The needle 6 is provided so as to move a predetermined amount toward the orifice 5 against the urging force of the spring 8. The needle 6, the spring holder 7 and the spring 8 are attached to a predetermined position upstream of the orifice inside the valve body by the needle holder 9.

  The gas flow flowing through the main flow path 4 flows from the upstream side of the orifice provided with the needle 6 through the gap 10 between the tip of the needle 6 and the orifice 5 to the downstream side of the orifice, and then flows out from the constant flow valve.

  In addition, in the valve body 1, a bypass flow path 11 that leads gas from the upstream side to the downstream side of the orifice 5 is formed separately from the main flow path 4 of the gas passing through the orifice 5. The bypass flow path 11 is a path for introducing gas from a valve seat opening 12 provided on the side of the main flow path on the upstream side of the orifice, and leading the gas again to the main flow path 4 from the opening 13 on the downstream side of the orifice. In the present embodiment, the bypass body 11 is formed by perforating the valve body 1 from the outside, and a sinking plug 30 is embedded in order to block gas leakage from an opening formed by perforation.

  The bypass flow path 11 is provided with a flow rate adjusting valve 20 facing the valve seat opening 12. The flow regulating valve 20 has a configuration in which a valve body holder 21 fixed to the valve body 1 holds a bypass valve body 22. The bypass valve body 22 is screwed with the valve body holder 21 while maintaining the airtightness of the bypass flow path 11, and moves forward and backward with respect to the valve seat opening 12. Further, the flow rate adjusting valve 20 includes a rotation operation unit 23 for moving the bypass valve body 22 forward and backward with respect to the valve seat opening 12. By rotating the rotation operation unit 23 in the R direction, the bypass valve body is provided. 22 is configured to advance and retract with respect to the valve seat opening 12. When the bypass valve body 22 comes into contact with the edge of the valve seat opening 12, the bypass flow path 11 is closed, while the bypass valve body 22 moves backward from the valve seat opening 12, thereby bypassing the bypass valve body 22 and the valve seat opening 12. The valve opening gradually increases and the gas flow rate through the bypass passage 11 increases. Therefore, adjustment of the flow rate of the gas flowing through the bypass passage 11 is performed by changing the valve opening degree of the bypass valve body 22 by rotating the rotation operation unit 23.

  By the way, in order to change the valve opening degree of the bypass valve body 22 from the minimum opening degree (closed state) to the maximum opening degree, it is difficult to operate the rotation operation part 23 and it is difficult to operate the rotation operation part 23. There is an inconvenience that it is difficult to grasp how much the valve opening is at a glance. Therefore, in the constant flow valve of the present embodiment, the rotation range of the rotation operation unit 23 required to change the valve opening degree of the bypass valve element 22 from the minimum opening degree to the maximum opening degree is set to one rotation or less, and the valve element holder A scale plate 24 for the rotation operation unit 23 is attached to 21. Since the rotation range of the rotation operation unit 23 is within one rotation, the rotation operation unit 23 can be operated more easily, and the scale plate 24 is attached. It will be easy.

  Next, the operation of the constant flow valve having the above configuration will be described. As described above, the needle 6 is urged away from the orifice 5. At this time, when the gas flow rate flowing through the constant flow valve increases, the needle 6 approaches the orifice 5 against the biasing force of the spring 8, and the gas flow path in the gap 10 between the orifice 5 and the needle 6 becomes narrower, and the main flow path. 4 is limited to a constant flow rate. Conversely, when the gas flow rate decreases, the force that pulls the needle 6 toward the orifice 5 decreases, the needle 6 moves away from the orifice 5 by the biasing force of the spring 8, and the gas flow path between the orifice 5 and the needle 6 increases. . Therefore, in this constant flow valve, the function of restricting the gas flow rate to a constant value works by the operation of the needle 6 according to the flow rate of the gas flowing through the main flow path 4.

  In this way, when the gas flow rate limited to a constant flow rate is lower than the rated evaporation capacity of the evaporator, the flow rate adjusting valve 20 is adjusted to flow the gas to the bypass flow path 11, and the shortage of the limited gas flow rate Can be supplemented by bypass flow. An example of the procedure is as follows. First, the bypass valve element 22 of the flow rate adjusting valve 20 is brought into contact with the edge of the valve seat opening 12 to close the bypass flow path 11, and the gas flow rate flowing through the constant flow valve is measured in this state. When the measured gas flow rate is less than a desired flow rate such as the rated evaporation capacity of the evaporator, the rotation operation unit 23 is rotated to gradually increase the valve opening degree of the bypass valve body 22 and to determine the constant flow rate. The rotation operation unit 23 is fixed when the gas flow rate flowing through the flow rate valve reaches a desired flow rate. By using the constant flow valve in this fixed state, the gas flow rate flowing through the constant flow valve substantially matches the rated evaporation capacity of the evaporator. Therefore, this constant flow valve does not require additional processing of each member such as an orifice and a spring, and can realize an appropriate restricted flow rate by an extremely simple adjustment operation.

  By the way, when the gas flow rate in the main flow path 4 increases and the needle 6 approaches the orifice 5 and reaches the uppermost position (position closest to the orifice 5) where the needle 6 can move, Thereafter, even if the gas flow rate is further increased, the positional relationship between the needle 6 and the orifice 5 does not change, and a fixed orifice state is obtained. For this reason, the flow restriction as a constant flow valve does not function under such usage conditions. Therefore, in order to avoid this state, it is preferable to design and use the pressure difference between the upstream side and the downstream side of the constant flow valve within a certain range according to the use conditions. Hereinafter, an example of such usage will be described.

  FIG. 2 is a view showing a configuration example of a gas supply device using the above-described constant flow valve, and this gas supply device is configured to supply gas from a storage tank 40 storing liquefied petroleum gas to the combustion device. Is done. Since the liquefied petroleum gas has a low boiling point and is vaporized in a normal temperature and normal pressure atmosphere, a two-phase is formed in the storage tank 40, that is, a liquid phase composed of a liquefied petroleum gas and a gaseous gas phase from which the liquid is evaporated. . When the outside air temperature is high and the pressure in the storage tank 40 is high, such as in summer, the gas phase line 41 for taking out the gas from the gas phase and supplying it directly to the combustion device, and the consumption of the natural vapor gas in winter and There is provided a liquid phase line 42 that extracts liquid from the liquid phase when the pressure in the storage tank 40 is lowered and supplies gas to the combustion device via an evaporator.

  In the middle of the gas phase line 41, manual valves 43 and 44 and a pressure adjusting valve 45 are provided. On the other hand, the liquid phase line 42 has parallel lines 42a and 42b branched into two in the middle, and evaporators 51 and 61 are provided in the parallel lines 42a and 42b, respectively. The parallel lines 42a and 42b join again at the downstream side to form one line. Note that the liquefied petroleum gas is in a gaseous state downstream of the evaporators 51 and 61. In such a liquid phase line 42, a manual valve 46 and a pressure gauge 71 are provided on the upstream side of the branch part, and a pressure gauge 76 and a manual valve 47 are provided on the downstream side of the junction part. The parallel line 42a is provided with a pressure gauge 72, a pressure adjustment valve 52, a pressure gauge 73, a constant flow valve 53, and a manual valve 54 in this order on the downstream side of the evaporator 51, and the other parallel line 42b has A pressure gauge 74, a pressure adjustment valve 62, a pressure gauge 75, a constant flow valve 63, and a manual valve 64 are provided in this order on the downstream side of the evaporator 61. The constant flow valves 53 and 63 are constant flow valves configured as described above. The downstream side of the manual valve 44 in the gas phase line 41 and the downstream side of the manual valve 47 in the liquid phase line 42 merge to form one pipe, and then to the combustion device via the final pressure adjustment valve 48. Gas supply is performed.

  In this way, in a gas supply apparatus having a configuration in which a plurality of evaporators are installed in parallel in a liquid phase line, for example, if a drift occurs such that the gas flow rate of one parallel line increases and the other parallel line decreases, The evaporator with a large flow rate becomes overloaded, and the liquefied petroleum gas spill prevention function is activated, making it impossible to supply gas stably. Therefore, the gas flow rate flowing through each parallel line is preferably within the rated evaporation capacity of the evaporator of each line, and the constant flow valves 53 and 63 should limit the gas flow rate flowing through each parallel line 42a and 42b to an appropriate state. Is provided. In addition, pressure adjusting valves 52 and 62 are provided in each parallel line so that the flow restriction function of the constant flow valves 53 and 63 is always effectively exhibited in each parallel line 42a and 42b. That is, by operating the pressure regulating valves 52 and 62, the pressure difference between the upstream side and the downstream side of the constant flow valves 53 and 63 can be adjusted to be within a certain range.

  As the liquefied petroleum gas, for example, liquefied propane gas or liquefied butane gas may be used alone, or a mixed gas obtained by mixing them at an arbitrary ratio may be used. In order for the constant flow valves 53 and 63 to always function effectively as described above, it is necessary to adjust the pressure regulating valves 52 and 62 according to the use conditions of the liquefied petroleum gas.

For example, when it is desired to always maintain the restricted flow rate by the constant flow valves 53, 63 regardless of the composition of the liquefied petroleum gas used in the gas supply device, the pressure gauges 52, 62 are operated to operate the pressure gauges. The pressure values indicated by 73 and 75 are adjusted as indicated by the adjustment line P1 in FIG. That is, when 100% liquefied butane gas is used, the pressure control valves 52 and 62 are adjusted so that the pressure gauges 73 and 75 indicate 0.07 (MPa), and the mixing ratio of liquefied propane gas increases. The pressure is adjusted so that the upstream pressure of the constant flow valves 53 and 63 increases in proportion. When 100% liquefied propane gas is used, the pressure control valves 52 and 62 are adjusted so that the pressure gauges 73 and 75 indicate 0.09 (MPa). At this time, the pressure gauge 76 after the parallel lines 42a and 42b join together is a pressure lower by about 0.02 (MPa) than the pressure value indicated by the pressure gauges 73 and 75, or the pressure value indicated by the pressure gauges 73 and 75. The same pressure is shown, and the pressure difference between the upstream side and the downstream side of the constant flow valves 53 and 63 is a pressure difference that can sufficiently exhibit the flow rate limiting function in this embodiment. Therefore, by performing the pressure adjustment according to the adjustment line P1 of FIG. 3, the gas flow rate flowing through each parallel line 42a, 42b can always be maintained in a constant state regardless of the gas composition.

Further, there is a case where the pressure value indicated by the pressure gauges 73 and 75 is always desired to be 0.07 MPa (0.7 kg / cm 2) regardless of the composition of the liquefied petroleum gas used in the gas supply device. For example, when the gas composition is changed throughout the year, and when the gas composition is changed, the pressure value indicated by the pressure gauges 73 and 75 is not changed, and the gas gauge is always used in a fixed state of 0.07 MPa. is there. In this case, even if the gas composition changes, the pressure difference between the upstream side and the downstream side of the constant flow valves 53 and 63 becomes a value within a certain range that can sufficiently exhibit the flow rate limiting function. It will not disappear. However, in this case, the limited flow rates of the constant flow valves 53 and 63 change according to the gas composition. FIG. 4 is a diagram showing changes in the restricted flow rate according to the gas composition. As shown in FIG. 4, when 100% liquefied butane gas is used, if the constant flow rate of the constant flow valve is 100%, the constant flow valve restriction is proportional to the increase in the mixing ratio of the liquefied propane gas. The flow rate gradually decreases, and the limit flow rate is reduced to 92% when 100% liquefied propane gas is used. Therefore, in this case, the gas supply device is used such that the gas consumption in the combustion device does not exceed the sum of the limited flow rates of the constant flow valves 53 and 63.

It is a figure which shows the structure of the constant flow valve which concerns on this invention. It is a figure which shows the example of 1 structure of the gas supply apparatus which uses the constant flow valve of this invention. It is a figure which shows the one aspect | mode of the pressure adjustment according to a gas composition. It is a figure which shows the one aspect | mode of the restriction | limiting flow volume change according to a gas composition.

Explanation of symbols

1 Valve body 4 Main flow path 5 Orifice 6 Needle 8 Spring (elastic means)
11 Bypass passage 12 Valve seat opening (valve seat)
20 Flow control valve 22 Bypass valve body 23 Rotation operation part 24 Scale plate

Claims (5)

An orifice is provided in the main flow path of gas inside the valve body, and a needle urged in a direction retreating from the orifice by a spring that applies an elastic force in a contracting direction is provided so as to be movable by a predetermined amount toward the orifice. When the flow rate is small, the needle retreats from the orifice due to the biasing force of the spring to enlarge the gas flow path, while when the gas flow rate is large , the needle approaches the orifice against the biasing force of the spring and opens the gas flow path. A constant flow valve that is small and is in a fixed orifice state when the needle is located at the highest movable position ,
A constant flow valve characterized in that a bypass flow path for guiding gas from the upstream side to the downstream side of the orifice is formed inside the valve body, and a flow rate adjusting valve is provided in the bypass flow path. The flow regulating valve includes a bypass valve body that moves forward and backward with respect to a valve seat provided in the bypass flow path, and closes the bypass flow path when the bypass valve body contacts the valve seat. 2. The constant flow valve according to claim 1, wherein the valve opening gradually increases as the body moves backward from the valve seat. The flow rate adjusting valve includes a rotation operation unit that advances and retracts the bypass valve body with respect to the valve seat, and changes a valve opening degree of the bypass valve body according to rotation of the rotation operation unit. The constant flow valve according to claim 2. The constant flow valve according to claim 3, wherein a rotation range of the rotation operation unit is within one rotation. The constant flow valve according to claim 3 or 4, wherein a scale plate is attached to the rotation operation portion.

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