Patent Application
20160047479
The present application claims the benefit of and priority to Japanese Patent Application No. 2014-164392, filed on Aug. 12, 2014, the entire contents of which is incorporated herein by reference.
The present invention pertains to a governor provided between a primary side channel and a secondary side channel to circulate fluid from the primary side channel to the secondary side channel while adjusting the pressure in the secondary side channel.
To circulate fluid while adjusting the fluid pressure, a diaphragm governor is installed at the connection between the primary side piping (primary side channel) and the secondary side piping (secondary side channel). See, for example, Patent Document 1. A diaphragm governor is configured such that a valve is interlocked with a diaphragm that is displaced according to the pressure in the secondary side channel, which is detected by a pressure detector, and when the detector detects a drop in the pressure in the secondary side channel, the valve opens, and when the detector detects a rise in the pressure in the secondary side channel, the valve shuts. The pressure detector is connected to the secondary side channel through an adjusting tube, and pressure can be conducted from the secondary side channel to the pressure detector.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. H11-212655 A.
With a governor configured as described above, when the pressure in the primary side channel rapidly rises with the valve in an open state, the high-pressure fluid flows through the secondary side channel and the adjusting tube to the pressure detector. Then, because the pressure in the pressure detector rapidly rises, the valve shuts, but because time passes until the high-pressure fluid passes through the secondary side channel and the adjusting tube and reaches the pressure detector, time also passes between the rapid rise of the pressure in the primary side channel and the shutting of the valve, and the response of the governor is therefore inferior. In addition, because time passes until the valve shuts, a considerable amount of high-pressure fluid flows through the secondary side channel and adjusting tube to the pressure detector, and the pressure in the pressure detector sharply rises all at once. As a result, when the pressure in the primary side channel rapidly rises, a large force impacts the parts involved in the valve shutting operation, thereby damaging said parts, and the pressure fluctuation in the primary side channel is accompanied by significant fluctuation also in the secondary side channel.
An object of the present invention is to solve the above problems by providing a governor capable of preventing damage to parts when the pressure in the primary side channel rapidly rises, and of alleviating pressure fluctuation in the secondary side channel.
The governor according to the present invention is provided with a pressure detection chamber, which connects to the secondary side channel through the adjusting tube; a diaphragm, which divides the inside and outside of the pressure detection chamber and is displaced according to the pressure in the pressure detection chamber; a valve stem provided at one end of a valve body and which moves in proportion to the displacement of the diaphragm; a connecting part, which connects the diaphragm and the valve stem and transmits the diaphragm displacement to the valve stem; and a non-return valve provided further upstream than the connection between the secondary side channel and the adjusting tube and which sends the fluid inside the secondary side channel to the pressure detection chamber.
According to the present invention, a non-return valve is provided further upstream than the connection between the secondary side channel and the adjusting tube, and because the non-return valve is capable of passing fluid from the primary side channel, which is further upstream than the adjusting tube, to the pressure detection chamber, when the pressure in the primary side channel rapidly rises, the governor switches to a closed state within a short amount of time, and as a result, damage to connected parts and other such parts can be prevented, and pressure fluctuation in the secondary side channel can be alleviated.
A connecting part 15, which connects the diaphragm 11 and the valve stem 14, and transmits the displacement of the diaphragm 11 to the valve stem 14, is provided in the pressure detection chamber 13. The valve stem 14 is connected to the connecting part 15 at one end (right side on the page), and penetrates through a shield plate 16, which partitions the pressure detection chamber 13 and the secondary side channel 3, and at the other end (left side on the page), a valve 17 is provided to open and close a port 4, touching and separating from a valve seat 41 provided at the port 4.
A non-return valve 19 is provided at the shield plate 16 to prevent the passage of fluid from the pressure detection chamber 13 to the secondary side channel 3 while allowing the passage of fluid from the secondary side channel 3 toward the pressure detection chamber 13.
In the non-return valve 19 configured in this manner, if the pressure on the secondary side channel 3 side as viewed from the non-return valve 19 increases by a prescribed amount or more above the pressure on the pressure detection chamber 13 side, this pressure difference opposes the biasing force of the spring 19c and causes the valve body 19b to move away from the inner wall 16b, and fluid is passed from the secondary side channel 3 toward the pressure detection chamber 13. In addition, the prescribed amount thereof, which is used as a standard for opening the non-return valve 19, is set in accordance with the biasing force of the spring 19c, or in other words, with the specifications of the spring 19c. If the pressure on the secondary side channel 3 side as viewed from the non-return valve 19 does not rise to the prescribed amount above the pressure on the pressure detection chamber 13 side, because the biasing force of the spring 19c causes the valve body 19b to push against the inner wall 16b, fluid is not passed from the secondary side channel 3 toward the pressure detection chamber 13. If the pressure on the pressure detection chamber 13 side as viewed from the non-return valve 19 rises above the pressure on the secondary side channel 3 side, this pressure difference and the biasing force of the spring 19c cause the valve body 19b to push against the inner wall 16b, and therefore fluid is not passed from the pressure detection chamber 13 toward the secondary side channel 3.
Next, the operation of the governor 1 is explained. When a demand for fluid arises downstream from the secondary side channel 3 and the pressure in the secondary side channel 3 drops, the pressure in the pressure detection chamber 13, which is connected to the secondary side channel 3 through the adjusting tube 6 also drops, and as a result, the diaphragm 11 is biased by the spring 12 and is displaced in the downward direction of the page. When the diaphragm 11 is displaced downward, the connecting part 15 acts so as to move the valve stem 14 in a direction to the right on the page, and to move the valve body 17 away from the valve seat 41. Thus, the port 4 is opened and a valve opened state is achieved.
If further demand for fluid arises and the pressure in the secondary side channel 3 drops even more, the diaphragm 11 is further displaced downward, the valve body 17 moves further away from the valve seat 41 and the opening grows bigger, and as a result, the pressure in the secondary side channel 3 is increased. If the demand for fluid decreases and the pressure in the secondary side channel 3 rises, the diaphragm 11 receives the rise in pressure in the pressure detection chamber 13 and is displaced upwards, the valve body 17 moves towards the valve seat 41, and the opening becomes smaller, and as a result, the pressure in the secondary side channel 3 is reduced. In such a way, the governor 1 adjusts the pressure in the secondary side channel 3. Furthermore, because during this operation there is almost no pressure difference before and after the non-return valve 19, the fluid in the secondary side channel does not flow into the pressure detection chamber 13 through the non-return valve 19.
Incidentally, with the governor 1, in addition to the pressure fluctuation within the secondary side channel 3 caused by the demand for fluid, which arises downstream of the secondary side channel as described above, pressure fluctuation also occurs within the primary side channel 2. Pressure fluctuation in the primary side channel 2 originates in the opening and closing of a valve (not illustrated) provided upstream of the primary side channel 2, and especially if the opening of this valve suddenly grows, the pressure in the primary side channel 2 abruptly rises. When the pressure in the primary side channel 2 abruptly rises and high-pressure fluid starts to pass through the port 4, the pressure of the port 4 within the secondary side channel 3 and of the portion surrounding the shield plate 16 (hereinafter, these parts are referred to as “space R”) abruptly rises. In other words, if the pressure on the secondary side channel 3 as viewed from the non-return valve 19 rises above the pressure in the pressure detection chamber 13 by more than a prescribed amount, the fluid that passes port 4 and reaches the space R flows into the pressure detection chamber 13 through the non-return valve 19. As a result, the pressure in the pressure detection chamber 13 rises and the diaphragm 11 is pushed in the upward direction of the page, the valve body 17 moves toward the valve seat 41, and the governor 1 enters a state of a closed valve.
Thus, because the fluid from the primary side channel 2, which has passed through the port 4, immediately enters the pressure detection chamber 13 through the non-return valve 19 provided at the shield plate 16, the valve body 17 is seated and the governor 1 enters a state of a closed valve shortly after the beginning of the high-pressure fluid passage through the port 4, and the responsiveness of the governor 1 to pressure fluctuation in the primary side channel 2 is therefore improved. Furthermore, because the governor 1 enters a closed valve state within such a short time, the amount of high-pressure fluid that passes through the port 4 is decreased, and because this high-pressure fluid, which passed through the port 4, flows into the pressure detection chamber 13 through the non-return valve 19, the pressure in the pressure detection chamber 13 can be prevented from sharply rising. Through these measures, when the pressure in the primary side channel 2 rapidly rises, the diaphragm 11 is rapidly pushed up, preventing a large force from suddenly impacting the connecting part 15 and damaging the connecting part 15, while the pressure fluctuation in the secondary side channel 3 can be alleviated.
With the governor 100 configured as described above, when the pressure in the primary side channel 2 rapidly rises and high-pressure fluid passes through the port 4, the high-pressure fluid passes through the secondary side channel 3 and the adjusting tube 6 and eventually flows into the pressure detection chamber 13, and the governor 100 enters a closed valve state. In other words, time passes from the startup of high-pressure fluid passage through the port 4 until the governor 100 enters a closed valve state by only the extent of the high-pressure fluid passing through the secondary side channel 3 and the adjusting tube 6, and therefore the responsiveness of the governor 100 to pressure fluctuation in the primary side channel 2 deteriorates. Moreover, since time passes until the governor 100 enters a closed valve state, a large amount of high-pressure fluid passes through the port 4, and because the configuration is not such that the same degree of resistance to the fluid flow as the non-return valve 19 is provided, by the time that the large amount of high-pressure fluid that has passed through the port 4 passes through the secondary side channel 3 and the adjusting tube 6 and reaches the pressure detection chamber 13, the pressure in the pressure detection chamber 13 sharply rises all at once. As a result, when the pressure in the primary side channel 2 rapidly rises, the diaphragm 11 is suddenly pushed upward, and a large force abruptly acts on the connecting part 15 and damages the connecting part 15, and the pressure fluctuation in the primary side channel 2 is accompanied by significant fluctuation within the secondary side channel 3 as well.
In contrast, the governor 1 according to Embodiment 1 of the present invention is provided with a non-return valve 19 at the shield plate 16. Because the fluid from the primary side channel 2 flows into the pressure detection chamber 13 through this non-return valve 19 faster than through the secondary side channel 3 and the adjusting tube 6, the governor 1 enters a closed valve state within a short amount of time. Therefore, when the pressure in the primary side channel 2 rapidly rises, the diaphragm 11 is not suddenly pushed upward, a large force does not abruptly impact the connecting part 15 and damage the connecting part 15, and the pressure fluctuation in the primary side channel 2 is not accompanied by significant fluctuation in the secondary side channel 3.
Note that with the above-described governor 1, a case was described for which the non-return valve 19 is provided at the shield plate 16, but the position at which the non-return valve 19 is provided is not limited thereto. For example, the pressure detection chamber 13 and the secondary side channel 3 can be connected by a branch pipe 7 (shown by the dotted line in
Furthermore, although two non-return valves 19 were illustrated and described above, the number of the non-return valves installed may be appropriately designed according to the properties of the non-return valve 19, such as the minimum differential pressure necessary to open the valve. Moreover, although a spring-type non-return valve was used as the non-return valve 19 in the example above, other non-return valves, such as a ball-type non-return valve, may also be used.
As described above, according to the governor 1 of the Embodiment 1 of the present invention, the non-return valve 19 is provided further at the primary side channel 2 side than the connection 5, and the non-return valve 19 is capable of passing fluid from the primary side channel 2 further upstream than the adjusting tube 6 to the pressure detection chamber 13. As a result, when the pressure in the primary side channel 2 rapidly rises, the governor 1 enters a closed valve state within a short amount of time, and the diaphragm 11 is rapidly pushed upward, thereby preventing a large force from suddenly acting on the connecting part 15 and damaging the connecting part 15, while the pressure fluctuation within the secondary side channel 3 can be alleviated.
In addition, a shield plate 16, which partitions the pressure detection chamber 13 and the secondary side channel 3, is provided, the valve stem 14 penetrates the shield plate 16 with the valve body 17 in a state of being arranged in the secondary side channel 3, and the non-return valve 19 is provided in the shield plate 16. Therefore, when pressure fluctuation is generated in the primary side channel 2, because a non-return valve 19 is provided in the shield plate 16 near the port 4, which is readily impacted by pressure fluctuation, when the pressure in the primary side channel 2 rapidly rises, the governor 1 enters a closed valve state within a particularly short amount of time.
In addition, within the scope of the invention of the present application, any structural component of the embodiment can be changed and any structural component of the embodiment can be omitted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-164392 | Aug 2014 | JP | national |
