WO2001062059A1

WO2001062059A1 - Arrangement in connection with an activator

Info

Publication number: WO2001062059A1
Application number: PCT/FI2001/000144
Authority: WO
Inventors: Juha Aimo
Original assignee: Tasowheel Oy
Current assignee: Tasowheel Oy
Priority date: 2000-02-15
Filing date: 2001-02-15
Publication date: 2001-08-23
Anticipated expiration: 2002-08-15
Also published as: FI120481B; FI20000318L; FI20000318A0

Abstract

An arrangement in connection with an electromechanical actuator, which actuator includes electrical components in a housing (1), such as a power unit (3) and control electronics (15), further a transmission mechanism (7), (14) of motion from said power unit to the movable member (13) of the actuator, and in which arrangement a major part of the actuator is placed in a space with a temperature over 120 C. For the actuator a cooling flow is arranged that is conducted at least to the housing (1) and out from it, and that the arrangement includes regulating devices for control of pressure formed in the housing or of temperature.

Description

ARRANGEMENT IN CONNECTION WITH AN ACT I VATOR

The invention relates to an arrangement in connection with an electromechanical actuator, which actuator includes electrical components in a housing, such as a power unit and control electronics, further the transmission mechanism of motion from said power unit to the movable member of the actuator, and in which arrangement a major part of the actuator is placed in a space with a temperature over 120 C.

Previously known, among others from the Finnish application publication No. 954712, are air blowing arrangements for electric housings in dirty environment, where compressed air flow of low pressure level from a compressed air driven device is conducted into a housing of electric equipment, which is in connection with the device. It is not intention to use the air flow for cooling but the aim is to keep with it clean air in the housing all the time and, possibly, also overpressure, so that air from dirty environment would have no access into the housing.

The actuator as per publication FI 954712, is placed with regard to its temperature to quite a normal environment, whereat no cooling is needed. Neither does the actuator produce any heat. The arrangement is suited only for an actuator using compressed air.

The arrangement as per this invention solves problems arising when actuators are mounted into hot locations. The invention is characterized in what is presented in the characterizing parts of the patent claims.

By means of this invention cooling problems in connection with actuators used in a hot location are solved. For instance, the construction of the steam distributing valve can be made short, though a major part of the valve is in a hot steam space and conducts heat out of there to the electric components and bearing members of the valve. By means of the housing the cooling flow can be controllably conducted to the most important, cooling requiring components, e.g. the electric power unit, the motor for instance. When the pressure of flow to be conveyed to the housing is regulated and, likewise, the quantity of flow at least by one regulating element that is placed either in the inlet or outlet, the produced cooling effect remains uniform enough.

In the following the invention is disclosed with reference to the enclosed drawing, where

Fig. 1 shows the actuator end with housing and a part of the components in profile. Fig. 2 shows the embodiment of figure 1 viewed from another direction and in profile. Fig. 3 shows a steam valve actuator without housing in profile.

In figure 1 there is mounted by means of flange 8 on the steam distribution tube surface a steam valve actuator comprised of body parts 9 and 6. On the surface of body part 6 housing 1 is fastened by means of fixing component 2. In the housing there is an electric motor 3 rotating by means of gearing 7 the axle leading to the valve spindle. In addition to motor 3 there can also be regulating electronics in the housing to control the valve and an electronic or mechanical thermostat element to adjust the air flow or the pressure. It is also possible to place into the housing a temperature sensor to measure the temperature or, for instance, a bimetal element for direct adjustment of the flow of cooling air. From the enlarged figure the conduction of the cooling flow through inlet 4 along channels 10 and 11 to the housing can be seen. The flow is let out, for instance, through inlet 5 from the housing,

Figure 2 shows the figure 1 embodiment seen from another direction. There is between housing 1 bottom and body part 6 a packing, advantageously of heat insulating material, as cork.

Figure 3 shows, also included in the housing, a steam valve member, an axle 14 and a valve spindle 13, which is a regu lating and closing member, the motion of which is upward.

About the valve spindle there is a cylinder body, partly open, placed in the steam distributing tube and through the openings of which steam can enter the cylinder and the closing mernber regulate the outlet of steam through the hole in the cylinder bottom.

The quantity of flow is determined and the pressure regulated by means of at least one regulating element in connection with the inlet 4 or outlet 5. Regulation is carried out by means of the temperature sensor or the thermostat element in the housing. Most suitably the pressure of the cooling flow is regulated a little higher than the steam pressure in the valve, so that no steam would leak alongside the valve spindle and axle towards the housing. For instance, if the steam pressure is 1 bar, a pressure of 1,5 bar, for instance, is chosen for the cooling flow. As flow medium water or inert shielding gases are used. For instance, in connection with assemblies 4 and 5 the housing can have a pressure relief valve, a shut-off valve, a safety valve and a valve regulating the quantity of flow. By means of the actuator gas or liquid flows, for instance, are regulated.

Claims

PATENT CLAIMS

1. An arrangement in connection with an electromechanical actuator, which actuator includes electrical components in a housing (1), such as a power unit (3) and control electronics (15), further a transmission mechanism (7),(14) of motion from said power unit to the movable member (13) of the actuator, and in which arrangement a major part of the actuator is placed in a space with a temperature over 120 C, characterized in that for the actuator a cooling flow is arranged that is conducted at least to housing (1) and out from it, and that the arrangement includes regulating devices for control of pressure formed in the housing or of temperature .

2. An arrangement according to patent claim 1 characterized in that the cooling medium is compressed air and in order to regulate pressure there is a regulating element either in connection with inlet (4) or outlet (5) or both of them.

3. An arrangement according to patent claim 1 and 2 characterized in that as pressure, active inside the housing, a higher pressure has been chosen than that of the gas or liquid flow regulated by means of the actuator.

4. An arrangement according to patent claim 1 characterized in that the quantity of cooling flow steered into the actuator housing is regulated by means of information received from the temperature sensor.

5. An arrangement according to patent claim 1 characterized in that the quantity of cooling flow steered into the actuator housing is regulated by means of the thermostat element, e.g. a bimetal eleneήt.