JPS5999016A - Impulse valve for steam engine - Google Patents

Abstract

PURPOSE:To reduce an irreversible loss and increase effective work of a steam engine by delaying the closing timing of an inpulse valve relative to its opening timing so that its opening and closing timings may be asymetric relative to the top dead center, that is, the time span up to the top dead center is shortened. CONSTITUTION:When a piston 12 moves upward and approaches to the top dead center, its projection 23 pushes an impulse valve 20 upward. Because of this, an intake port 17 is opened to allow the steam having a pressure P1 flows from a space 18 in a cylinder head 10 to a cylinder 11. Also, a vent hole 19 is closed, and a check valve 25 is opened due to a rise in the pressure P2 in a cylinder section 15 to communicate the cylinder section 15 and the space 18. When the impulse valve 20 moves downward and the pressure P2 is lowered, the check valve 22 is closed, and a negative pressure is generated in the cylinder section 15 due to the adiabatic expansion to delay the downward movement of the valve 20. By this arrangement, the impulse valve 20 moves downward separately from the piston 12 so that the closing timing can be delayed compared to the opening timing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam artificial valve in a reciprocating type expander of a steam engine, and relates to an impulse valve for a steam engine that is opened and closed by a gust provided at the top of a piston.

A conventional impulse valve of this type is shown in FIG.

The operating principle of this is that the steam filling the cylinder head 1 reaches the top dead center (T, D, C) during the upward stroke of the piston 2.
), the protrusion 3 provided on the top of the piston pushes up the impulse valve 4 to reach the maximum opening area at top dead center, and steam enters the cylinder 6 through the ventilation port 5. After that, the piston 2 moves to a downward stroke, and the impulse valve 4 descends together with the piston 2 due to the urging force of the spring 7 of the valve part, and eventually comes into close contact with the valve seat 1g, and the steam in the cylinder 6 is trapped in a high temperature and high pressure state. , the piston 2 is pushed down by that energy, and ideally it expands adiabatically.

In this conventional mechanism, the following problems have become apparent.

That is, 1. Irreversible loss and mechanical loss when the impulse valve 4 is opened increases.

If the piston is pushed up and the valve hole is opened, the opening and closing timing of the impulse valve 4 will be at the top dead center, and the valve opening timing and valve closing timing will be evenly distributed (see Figure 2). , high-pressure steam flows into the cylinder, and the pressure inside the cylinder rises to the supply steam pressure.

The piston 2 performs work against the supplied steam pressure until the top dead center, and then performs work in the opposite direction until it closes.As a result, the work generated in the cylinder during the impulse valve opening period is There isn't.

Figure 3: Ideal P-V of impulse valve type expander
A diagram is shown.

From the above, (1) irreversible loss amount shown by the shaded area in FIG. 3 occurs. As shown in Figure 3, there is no work generated in the process of 6-+C→d, but during this period, steam supply pressure is constantly applied to the top of the piston, and only mechanical friction force is applied. The mechanical loss ratio increases with respect to the effective work done in the cylinder during one cycle, and the efficiency of the expander deteriorates.

The present invention has been made in consideration of the above-mentioned problems, and is designed to reduce the amount of irreversible loss and increase the effective work by the amount of the reduction in the amount of irreversible loss.

It is an object of the present invention to provide an impulse valve for a steam engine that can reduce the ratio of mechanical loss to effective work and reduce the decrease in expander efficiency due to mechanical loss.

The above object is achieved by making the valve lift curve asymmetrical, that is, by shortening the valve lift period up to the top dead center.

Embodiments of the present invention will be described below with reference to FIG.

In the figure, 10 is the cylinder head and +1 is the cylinder.

12 is a piston. An impulse valve device 13 is provided within the cylinder head 10 . A cylinder portion 15 is formed in a valve housing 14 of this impulse valve device 13, and a valve seat 16 facing upward is provided at a lower portion of this cylinder portion 15. Further, the upper side of the valve seat 16 of the cylinder portion 15 communicates with the ρ space 18 in the cylinder head 10 through an intake boat 17. Further, the upper part of the cylinder part 15 communicates with the space part 1g through a ventilation hole 19. In the cylinder portion 15, an impulse valve 20 facing the valve seat 6) is fitted and biased by a spring 21. A check valve 22 is provided at the top of the cylinder part 15 to allow flow only from the top of the cylinder part 15 to the space 1g in the cylinder head IO.The vent hole 19 provided in the cylinder part 15 is an impulse valve. When the impulse valve 20 is raised, the impulse valve 20 is opened at the closed position. A projection 23 is provided at the top of the piston 12 and comes into contact with the lower end surface of the impulse valve 20.

The operation of the above configuration will be explained below.

When the piston 12 rises and approaches the top dead center, its protrusion 23 comes into contact with the impulse valve 2o, and the impulse valve 20 is pushed up and raised, thereby filling the space 18 of the cylinder head 10.
Steam at pressure P1 flows into the cylinder 11 through the intake boat 17. At this time, when the impulse valve 2o rises, the communication hole 19 is closed, the pressure P inside the cylinder section 15 increases, the check valve 22 opens, and the cylinder section 15 and the space 18 of the cylinder head 10 communicate with each other. However, the pressure P of the cylinder portion and the pressure P of the cylinder head 10 are in equilibrium, and p,=pt.

After that, when the piston 12 passes the top dead center and enters the downward stroke, the impulse valve 20 is lowered by the biasing force F1 of the spring 21, and the intake boat 17 is throttled. In this way, due to this throttling effect, the lower side of the impulse valve 20 (cylinder name 1
(inside) pressure Ps of cylinder 1 of vine pulse valve device 13
5 becomes lower than the pressure P2, and becomes p,>p. Therefore, the impulse valve 20 has its differential pressure Cp2-ps) and the spring 2
It descends with a biasing force F of 1.

At this time, the impulse valve 20 descends and the cylinder portion 15
When the internal pressure P2 decreases, the check valve 22 is closed, and when the impulse valve 20 further descends in this state, negative pressure is generated in the cylinder part 15 of the impulse valve device 13 due to adiabatic expansion, and this causes the impulse valve 20 to acts upward,
The balance equation of the impulse valve 20 in the downward stroke of the impulse valve 20 that attempts to delay the downward movement of the impulse valve 20 is m a = (II Pm>/(l+ ji' + ”
V4 t・12・・・・・・(1) However, l, pressure receiving area l of coin pulse valve 20, cross-sectional area m of Niji cylinder part 15: mass α of impulse valve 20: acceleration of impulse valve 20 Note that the speed "p2/cLt-i!" is a negative value.

From the above balance equation, the addition m Kα of the impulse valve 20 is:

α”'m ((7'Ps) 7t + pm+p
2/d,,・Δ,)...(2) Therefore, the upward movement due to adiabatic expansion within the cylinder portion +5 is made so that the acceleration α of the impulse valve 20 determined by the above equation (2) is smaller than the acceleration β of the piston 12. If it is set up so that (negative) force acts on it.

The impulse valve 20 moves downward away from the piston 12, so that the closing timing of the impulse valve 20 can be delayed from the opening timing, and the opening and closing timing of the impulse valve 20 becomes asymmetrical with respect to the top dead center of the piston 12.

FIG. 5 is a diagram showing the above state, and the impulse valve 20
The lift curve is the top dead center of the piston 12 (T, D, C
), and as a result, as shown in the PV diagram, the irreversible loss shown by diagonal lines is reduced compared to the case shown in FIG. 3, and the effective work increases accordingly.

Since the present invention is as described above, the lift curve of the impulse valve 20 during steam intake can be shifted to the side beyond the top dead center of the piston 12, and therefore irreversible loss in the steam engine can be reduced. 0, and since the effective work increases, the mechanical loss ratio to the effective work decreases, and the efficiency is improved compared to a normal impulse valve type expander, and moreover, the output per revolution is increased.

Further, according to the present invention, since the check valve 22 is provided above the cylinder portion 15 as a means for exerting an adiabatic expansion force within the impulse valve device, the above-mentioned operation for each cycle is reliably performed, and the steamy engine is Stable performance can be obtained during operation.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional impulse valve device of a steam engine, Fig. 2 is a diagram showing the relationship between the lift curve of the impulse valve and cylinder pressure in the conventional example, and Fig. 3 is a PV line in the conventional example. 4 is a sectional view showing an embodiment of the present invention, and FIG. 5 is a PV diagram of the embodiment of the present invention. 10 is a cylinder head, 11 is a cylinder, 12 is a piston, 14 is a housing, 15 is a cylinder part, Ilj: valve seat % 17 is an intake boat, 20 is an impulse valve,
22 is a check valve, 23 is a top protrusion 0 Applicant: Komatsu Ltd. Representative Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto 91 No. 1 Fig. 2 Mouth No. 3 Fig. 4 Fig.-92=

Claims (1)

[Claims] A valve housing 14 provided in the upper part of the cylinder 11 and inside the cylinder head 10 has an opening in the cylinder 11;
In addition, a cylinder part I5 having a valve seat 16 at the opening part is provided, and an intake port 17 communicating with the steam supply side is provided in this cylinder part 15. The impulse valve 20, which is pushed up by the protrusion 23 and communicates the intake port 17 and the cylinder 11, is fitted into the valve seat 16 with a spring bias, and the top of the cylinder part I5 and the steam supply side are connected. An impulse valve for a steam engine, characterized in that it communicates through a check valve 22 that allows flow only in the side direction of a cylinder portion 15.