Patent GB-809455-A (GB)
Title: Mechanical energy transducers particularly for converting a pressure change into a linear movement
IPC: B60H1/00
Filed: 1955-03-04
Abstract: 809,455. Temperature-responsive actuat ing-elements; fluid-circulating systems deriving heat from I.C. engines. STANDARDTHOMSON CORPORATION. March 4, 1955 [March 31, 1954; Dec. 24, 1954], No. 6530/55. Class 64(2) [Also in Group XXIX] By means of a metal diaphragm 214, Fig. 5, and a body 217 of deformable, incompressible material such as a moulded body of rubber to which lubricants have been added before moulding, a pressure change transmitted by a liquid, e.g. due to thermal expansion of the liquid, is converted to lineas movement of a spring-loaded pin 200 sliding in an opening of an enclosure 210 containing the diaphragm 214 and the body 217, the liquid being contained in a tube 130 communicating with another opening in the enclosure 210. A loop of the tube 130, Fig. 4 (not shown), is exposed to hot air leaving a car heater through which engine coolant is by-passed by a duct 114. The coolant passes through a valve seat 162 and ports 170, the valve 172 being operated by the pin 200 to close on an excessive temperature rise. The valve body 160 and duct 114 extend through an end wall 129 of the air heater into a header space 168. The end of the tube 130 is sealed into a disc 212 to which the diaphragm 214 is secured, e.g. by soldering at 216, to cover the disc's concave face, and this sealed end of the thermallyresponsive system is then secured in the mouth of a funnel-shaped member by spinning of the edges of the member, to form the top of the enclosure 210. The bottom of the body 217 is covered by a thin flexible insert 230 of tetrafluoroethylene polymer and is supported by a sleeve 218 in which the pin slides, and which completes the enclosure. An over-travel spring 204, for taking up any movement of the sleeve 218 when the pin 200 is held 'from further movement by closure of the valve 172, supports the sleeve by means of a washer 220. A metal or nylon disc 232 embedded in the body 217 protects the diaphragm 214. Expansion of the liquid in tube 130 causes compression of the body 217 so that the pin 200 is forced out of the enclosure 210 and pushes down the valve 172, in an upper stem of which it fits loosely, against the action of a spring 198 surrounding a lower valve-stem. The end of this lower stem is necked for securement by a locking ring 196 in a rubber diaphragm sealing the bottom of the valve body 160. The sleeve 218 normally stays in fixed relation to the enclosure 210 but if ambient conditions affect the volume of the body 217 a device containing a similar body 227 is also affected and compensates 'for any change in the volume. The compensating body 227 is contained in a shell 224 having a sleeve 222 surrounding a cylindrical extension of the enclosure 210 and supported by the washer 220 so that the whole compensating device is held in position by the spring 204. Expansion of the body 227 moves the sleeve 222 and washer 220 downwards to permit expansion of the body 217, without movement of the pin 200, by allowing downward movement of the inner sleeve 218. For manual setting of the device from the car dashboard, the other end of the tube 130 terminates in a disc similar to disc 212 adjacent to a diaphragm and incompressible body similar to those described but which are subjected to pressure from a hand-operated lever by way of a plunger so that operation of the lever exerts pressure on the thermally expansive liquid. In another embodiment, Fig. 7 (not shown), an enclosure similar to that 210 described is secured to a fixed plate while a shell containing an incompressible compensating body is adjustably secured by screwthread around the cylindrical extension of the enclosure. The compensating body acts directly on a shoulder of the inner sleeve to push the sleeve down and out of the enclosure upon expansion. The sleeve is supported directly by the overtravel spring which in turn is supported on a second fixed plate or, so that the pressure limit for over-travel remains constant for different adjustment positions of the shell, on an extension from the shell. The pin in this embodiment actuates through a member fitted on the end of the pin and protruding through the second fixed plate from which it is supported by another spring. In still another embodiment, Fig. 2 (not shown), for use in a car-heating system such as shown in Fig. 1, the valve 18 is operated acording to expansion of liquid in a tube 24 due to temperatures of loops 26, 28 outside and inside the vehicle. There is no compensation for ambient conditions in this embodiment and adjustment is by means of manually-controlled electric heating of a bulb 30 in the tube 24 or by screwing up or down a thimble 92 acting on the liquid, Fig. 3 (not shown), through a spring, a plunger, incompressible body and diaphragm. The spring can also take up excess pressure in the system. Specification 724,920 is referred to.