Loading patent…
AssigneeUnited Kingdom Atomic Energy Authority
InventorsJames Francis Pollock, Peter Douglas Dunn, Graham Rice, Basil Dixon Power
Estimating the term…
Fluid heating arrangements and methods are provided wherein liquid is caused to flow through a fluid permeable electrical resistance heater body. Prior to the heater body, the liquid passes through a fluid permeable flow control member which offers a uniform resistance to the entire flow of the liquid. Static pressure head of the fluid varies over the entry surface of the flow control member, and the permeability of the combination of the heater body and the flow control member are such as to cause a pressure drop in the fluid greater than the variations in static pressure head of the fluid at the entry surface of the flow control member. This promotes a uniform flow of the fluid through the heater body even in the presence of significant differences in static pressure head over the fluid entry surface of the flow control member. The permeability of the flow control member may be such that the pressure drop across the flow control member alone is greater than the variation in the static pressure head of the fluid over the entry surface of the flow control member.
In a fluid heating arrangement, a device for heating a fluid comprising a fluid permeable, porous, electrical resistance heater body having electrical input and output ends and a fluid entry surface, a fluid permeable, porous flow control member which covers the fluid entry surface of said heater body, said flow control member having a fluid entry surface, a fluid supply communicating with the entry surface of said flow control member, said flow control member being oriented such that the static pressure head of the fluid varies over the entry surface of the flow control member, the flow control member being made of a material which has a higher electrical resistance than the heater body, a lower thermal conductivity than the heater body, and a uniform distribution of interconnected pores throughout its entirety, the permeability of the combination of the heater body and the flow control member being such that the impedance of the heater body and the flow control member to flow of said fluid causes a drop in pressure in the fulid as it passes through the flow control member and the heater body, the total pressure drop in the fluid across the combination of the flow control member and the heater body in the general direction of fluid flow being greater than said variations in static pressure head of the fluid at the entry surface of the flow control member so as to promote a uniform flow of the fluid through the heater body even in the presence of significant differences in static pressure head over the fluid entry surface of the flow control member, said flow control member acting as a thermal impedance barrier such that heat generated by a heater body is transferred to the fluid permeating through the device but does not, by thermal or electrical conduction, or thermal radiation, heat the fluid at the entry surface of the flow control member to a temperature high enough to cause boiling in the fluid before it enters the flow control member.
A method of heating a liquid to vaporize it by causing the liquid to flow through a fluid permeable electrical resistance heater body which is heated to a temperature high enough to vaporize the liquid by electrical current therethrough, the method including the step, prior to passing the liquid through the heater body, of causing the liquid to flow through a fluid permeable flow control member in contact with and covering the fluid entry surface of the heater body, the flow control member offering a uniform resistance to the entire flow of the liquid and having a higher electrical resistivity than the heater body and a lower thermal conductivity than the heater body for subjecting fluid passing therethrough to a temperature gradient increasing from a temperature, at the entry surface of the flow control member, which is below that at which any liquid vapor bubbles form, up to the temperature generated in the heater body, the flow control member being oriented such that the static pressure head of the fluid varies over the entry surface of the flow control member, the permeability of the combination of the heater body and the flow control member being such that the impedance to fluid flow of the heater body and the flow control member causes a drop in pressure in the fluid as it passes through the control member and the heater body, the total pressure drop in the fluid across the combination of the flow control member and the heater body in the general direction of fluid flow being greater than said variations in the static pressure head of the fluid at the entry surface of the flow control member.
Dependencies are inferred from the claim text.