JPH01167559A - Air conditioner - Google Patents

Abstract

PURPOSE:To drive an electrically driving expansion valve with smaller power when opening the electrically driving expansion valve by setting the electrically driving expansion valve at prescribed opening in which refrigerant is not leaked from a fully closed lock point. CONSTITUTION:Since electrically driving expansion valves 4a, 4b are fully closed and pulse number is increased more than P2 in the time of pulse number P2 of a pulse motor 11, the opening of the valves 4a, 4b are enlarged gradually and the flow of the refrigerant is increased. Further, when the fully closed lock point of the valves 4a, 4b is made 0 and the valves 4a, 4b are opened therefrom, valve opening point lag is produced up to the pulse number P2. This is caused by screw friction of a screw part of a rod 17 for supporting a needle 13 and thermal deformation of the screw part caused by refrigerant of high temperature and high pressure. Thus, whenever the valves 4a, 4b are opened, unnecessary drive power is needed for some pulse and a time lag is produced. The valves 4a, 4b are set at prescribed opening in which the refrigerant is not leaked from the fully closed lock point 0, namely, set at pulse number P1 (P1<P2). Therefore, the startup of the valves 4a, 4b can be made rapid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner equipped with a refrigeration cycle having an electrically operated expansion valve.

[Conventional technology]

Conventionally, in this type of air conditioner, a control device incorporating a microcomputer adjusts the opening degree of an electric expansion valve according to the refrigerant temperature or refrigerant pressure in the refrigeration cycle, thereby controlling the refrigerant flow rate control Kl. ? : We are trying to save energy during cooling and heating operations.

Incidentally, related devices of this type include, for example, Utility Model Application Publication No. 60-39873, Utility Model Application Publication No. 59-65332, and the like.

[Problem that the invention seeks to solve]

However, in the prior art, when the electrically operated expansion valve opens from the zero opening state, that is, from fully open to a predetermined opening,
No consideration was given to the fact that, due to thread friction in the valve drive unit, a larger driving force is required to open the electric expansion valve than to close it, and this has led to problems with on/off operations.
When the off interval was short, there was a problem that the start-up was slow.

It is an object of the present invention to provide an air conditioner which solves the problems of the prior art, which can be driven with a relatively small force when opening an electric expansion valve, and which can prevent the valve opening from becoming clogged due to the thermal influence of high temperature and high pressure liquid refrigerant. The goal is to provide equipment.

[Means for solving problems]

The above object is achieved by setting the electric expansion valve to a predetermined opening degree that prevents refrigerant from leaking beyond the fully closed lock point.

[Effect]

When opening an electric expansion valve from fully closed to the required opening,
Due to screw friction in the valve drive unit, a larger driving force is required than when closing.

Therefore, in the present invention, the opening degree is set to a predetermined opening degree that prevents refrigerant from leaking from the fully closed lock point. Therefore, in the present invention, the driving force needed to open the electric expansion valve is relatively small, so even if the interval between operation on and off is short, startup can be made faster.

Furthermore, the present invention can also prevent valve openings from becoming clogged due to thermal effects from high-temperature, high-pressure liquid refrigerant.

〔Example〕

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

FIG. 1 is a refrigeration cycle system diagram of an air conditioner according to the present invention, FIG. 2 is a sectional view of an electric expansion valve incorporated in the present invention, and FIG. 3 is a diagram showing the refrigerant flow rate of the electric expansion valve and pulses generated by the pulse motor. It is a graph showing the relationship with numbers.

The air conditioner shown in FIG.
An indoor unit having indoor heat exchangers 5a and 5b is connected to the outdoor unit of the stand via a liquid side branch pipe and a gas side branch pipe, and the liquid side branch pipe is provided with electric expansion valves 4a and 4b. A heat pump refrigeration cycle is constructed in which these are connected in sequence. In this case, during cooling operation, the refrigerant flows in the direction of the solid arrow in the diagram, and during heating operation, the refrigerant flows through the four-way valve 2.
By switching, the refrigerant flows in the direction of the wavy line arrow in the figure.

The electric expansion valves 4a*4b, as shown in FIG.
A valve seat 14 provided in the valve body 12 and a needle 13 in contact with the valve seat 14 are provided, and the high temperature and high pressure liquid refrigerant entering from the inlet opening 15 is throttled between the needle 13 and the valve seat 14. It is brought to low temperature and pressure, and is discharged to the outlet opening g16 and supplied to the indoor heat exchanger 5a+5b or the outdoor heat exchanger 3. The electric expansion valves 4a and 4b have a reversible structure in which liquid refrigerant flows into the outlet opening 16 and is discharged to the inlet opening 15.

The rod 17 supporting the needle 13 is connected to the gear mechanism 1
The needle 13 is moved up and down by the rotational force of a pulse motor 11 through an 8ft shaft, and the distance between the needle 13 and the valve seat 14 is changed by the up and down movement of the rod 17, so that the aperture can be adjusted.

In FIG. 3, when the number of pulses of the pulse motor 11 is P2, the electric expansion valves 4a and 4b are fully closed, and when the number of pulses increases more than the number of pulses P2, the electric expansion valves 4a and 4b
a14b gradually becomes larger as the flow rate of the refrigerant increases.

Also, if the fully closed lock point of the electric expansion valves 4a+4b is set to 0 and the valves are opened from there, as can be seen from FIG.
Until the pulse number P2, a delay in the valve opening point occurs. this is,
This is due to thread friction of the threaded portion of the rod 17 that supports the needle 13, thermal deformation of the threaded portion due to high-temperature, high-pressure refrigerant, and the like. Therefore, each time the electric expansion valves 4a and 4b1 are opened, an additional driving force corresponding to a certain pulse is required, resulting in a time delay. Therefore, in this embodiment, the electric expansion valve 4a
, 4b is a predetermined opening at which no refrigerant leaks from the fully closed lock point 0,
In other words, in Fig. 3, the number of pulses P1 (tatashi, P□<P
2) is set.

As a result, even if the on-off interval during operation of the electric expansion valves 4a and 4b is short, startup can be made faster, and valve openings can be prevented from becoming clogged due to heat effects from high-temperature, high-pressure liquid refrigerant. be able to. In the actual example, the valve opening point delay was 90 pulses, so by setting it in the opening direction 40 pulses from the fully closed lock point 0, we prevented refrigerant from leaking and at the same time increased the driving force to open the electric expansion valve. I was able to make it smaller.

〔Effect of the invention〕

According to the present invention described above, since the electric expansion valve is set to a predetermined opening degree that prevents refrigerant from leaking from the fully closed lock point, the driving force required to open the valve from the conventional fully closed lock point is smaller than that required for opening the valve from the fully closed lock point. Even if the on/off interval is short, there is an effect of speeding up the start-up 9, and there is also an effect of preventing the valve opening from being clogged due to the influence of the liquid refrigerant at low temperature and high pressure.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a refrigeration cycle system diagram, FIG. 2 is a sectional view of an electric expansion valve, and FIG. 3 is a graph showing the relationship between the refrigerant flow rate of the electric expansion valve and the number of pulses generated by the pulse motor. 1...Compressor 2...Four-way valve 3...Outdoor heat exchanger 4a, 4b...Electric expansion valve 5a, 5
b... Indoor heat exchanger 8... Control device 11.
... Pulse motor 12 ... Valve body of electric expansion valve 13 ... Needle 14 ... Valve seat 1
5... Refrigerant inlet 16... Refrigerant outlet
17... Same robed. Fig. 1 1 Pressure transfer Mekari meeting, b electric ψh type eyelid root appetizer 2t [I7 valve 5a, b indoor storage tank alley 3 pin outside @ role ↑
Riharu 8 Place 1 plate

Claims (1)

[Claims] 1. One outdoor unit equipped with a frequency controllable compressor, outdoor heat exchanger, four-way valve, etc., and an indoor unit equipped with at least one indoor heat exchanger are connected to a liquid side branch pipe and a gas side branch pipe. An air conditioner comprising an electric expansion valve connected to the liquid side branch pipe through a liquid side branch pipe, characterized in that the electric expansion valve is set to a predetermined opening degree from a fully closed lock point to prevent refrigerant from leaking. Air conditioner.