Fluid preheating

Abstract

A heating system for preheating a fluid. The heating system comprises a heating unit with a heating flow path; wherein the heating unit is adapted to be operated at a first temperature and to provide a heat transfer between the heating unit and the fluid passing through the heating flow path, with the heat transfer not being sufficient for heating up the fluid passing through the heating flow path to the first temperature.

1 . A heating system for preheating a fluid, comprising: 
 a heating unit with a heating flow path;    wherein the heating unit is adapted to be operated at a first temperature and to provide a heat transfer between the heating unit and the fluid passing through the heating flow path, with the heat transfer not being sufficient for heating up the fluid passing through the heating flow path to the first temperature.    
   
   
       2 . The heating system of  claim 1 , wherein the heating flow path's outlet is fluidically coupled with a separation system, the separation system being adapted for separating compounds of a fluid sample.  
   
   
       3 . The heating system of  claim 1 , further comprising at least one feature selected from the group consisting of: 
 the heating unit is implemented such that the fluid's temperature after passing through the heating unit's heating flow path is lower than the first temperature;    the heating power of the heating unit is not sufficiently large and/or the heating unit's heating flow path is not sufficiently long for bringing the temperature of the fluid passing through the heating flow path to the first temperature;    the temperature of the fluid at the heating flow path's outlet depends on the thermal properties of the fluid passing through the heating unit's heating flow path; and    a variation of the fluid's composition gives rise to a variation of the fluid's thermal properties and to a corresponding variation of the fluid's temperature at the heating flow path's outlet.    
   
   
       4 . The heating system of  claim 1 , wherein the heating unit is an auxiliary heating unit with an auxiliary heating flow path, 
 wherein the heating system further comprises a main heating unit with a main heating flow path;    the main heating flow path's outlet being fluidically coupled with the auxiliary heating flow path's inlet, and    wherein the main heating unit is adapted to be operated at a second temperature being lower than the first temperature and to provide a heat transfer between the main heating unit and a fluid passing through the main heating flow path, with the heat transfer being sufficient for heating up the fluid passing through the main heating flow path to the second temperature.    
   
   
       5 . The heating system of  claim 4 , further comprising at least one feature selected from the group consisting of: 
 the main heating unit is located upstream of the auxiliary heating unit;    the main heating unit is implemented such that the fluid's temperature attains the second temperature when passing through the main heating unit's main heating flow path;    the heating power of the main heating unit is sufficiently large, and the main heating unit's main heating flow path is sufficiently long for bringing the temperature of the fluid passing through the main heating flow path to the second temperature;    the heating system comprises a sample injection unit located between the main heating unit and the auxiliary heating unit, with the sample injection unit being adapted for injecting a fluid sample into the fluid passing through the heating system; and    the heating system comprises a sample heating unit adapted for preheating the fluid sample before the fluid sample is provided to the sample injection unit.    
   
   
       6 . The heating system of  claim 1 , further comprising at least one feature selected from the group consisting of: 
 the main heating flow path is implemented as a first heat transfer capillary;    the auxiliary heating flow path is implemented as a second heat transfer capillary;    the capillaries' inner diameter lies in the range between 0.05 mm and 0.30 mm;    the heating unit is made of at least one of: cast iron, copper, aluminium, bronze; and    the heating unit comprises a plurality of switchable heater modules.    
   
   
       7 . A separation system comprising: 
 a heating unit for preheating a fluid, the heating unit comprising a heating flow path, wherein the heating unit is adapted to be operated at a first temperature and to provide a heat transfer between the heating unit and the fluid passing through the heating flow path, with the heat transfer not being sufficient for heating up the fluid passing through the heating flow path to the first temperature; and    a separation column adapted for separating compounds of a fluid sample, with the heating flow path's outlet being fluidically coupled with the separation column's inlet.    
   
   
       8 . The separation system of  claim 8 , further comprising at least feature selected from the group consisting of: 
 a fluid delivery unit, preferably a pump, located upstream of the heating unit and being adapted for moving the fluid in the separation system;    a sample injection unit located upstream of the heating unit and being adapted for injecting the fluid sample into a mobile phase of the separation system;    a detector located downstream of the separation column and being adapted for detecting separated compounds of the fluid sample; and    a controller adapted for controlling operation of the separation system.    
   
   
       9 . The separation system of  claim 8 , further comprising at least one feature selected from the group consisting of: 
 the fluid conveyed through the heating unit is a solvent, and the solvent's composition is kept constant during sample analysis;    the fluid conveyed through the heating unit is a composite solvent, and the solvent's composition is varied according to a gradient during sample analysis;    the fluid conveyed through the heating unit is a composite solvent, and a variation of the composite solvent's composition gives rise to a corresponding temperature variation of the composite solvent supplied to the separation system;    the temperature of the fluid further increases when passing through the separation column;    the separation system is one of: a liquid chromatography system, an electrophoresis system, an electrochromatography system;    the separation system comprises a thermostated column compartment adapted for keeping the separation column at a predefined temperature;    the temperature the thermostated column compartment is kept at is approximately equal to the first temperature; and    the thermostated column compartment is thermally coupled with the heating unit.    
   
   
       10 . The separation system of  claim 8 , further comprising at least one feature selected from the group consisting of: 
 the heating unit's heating power is varied in dependence on a feedback signal;    the heating unit comprises a plurality of switchable heater modules that may be activated in dependence on a feedback signal;    the feedback signal indicates the temperature of the fluid at the outlet of the heating unit;    the feedback signal indicates a quality of peak patterns acquired with the separation system; and    the heating unit's heating power is controlled in a closed-loop control operation.    
   
   
       11 . The separation system of  claim 8 , wherein the heating unit is auxiliary heating unit with an auxiliary heating flow path, 
 wherein the heating system further comprises a main heating unit with a main heating flow path;    the main heating flow path's outlet being fluidically coupled with the auxiliary heating flow path's inlet, and    wherein the main heating unit is adapted to be operated at a second temperature being lower than the first temperature and to provide a heat transfer between the main heating unit and a fluid passing through the main heating flow path, with the heat transfer being sufficient for heating up the fluid passing through the main heating flow path to the second temperature.    
   
   
       12 . The separation system of  claim 13 , further comprising at least one feature selected from the group consisting of: 
 a sample injection unit located between the main heating unit and the auxiliary heating unit, the sample injection unit being adapted for injecting the fluid sample into a mobile phase of the separation system; and    a sample heating unit adapted for preheating the fluid sample before the fluid sample is provided to the sample injection unit.    
   
   
       13 . A method for preheating a fluid, the method comprising: 
 conveying the fluid through a heating unit, the heating unit being kept at a first temperature, with the heat transfer during the fluid's passage through the heating unit not being sufficient for bringing the fluid's temperature to the first temperature; and    supplying the fluid to a separation system.    
   
   
       14 . The method of  claim 15 , wherein composition of the fluid conveyed through the heating unit is varied according to a gradient.  
   
   
       15 . The method of  claim 15 , wherein composition of the fluid conveyed through the heating unit is kept constant.  
   
   
       16 . The method of  claim 15 , wherein the heating unit is an auxiliary heating unit with an auxiliary heating flow path, 
 the method further comprising:    conveying the fluid through a main heating unit before supplying the fluid to the auxiliary heating unit, the main heating unit being kept at a second temperature, the second temperature being lower than the first temperature, with the heat transfer during the fluid's passage through the main heating unit being sufficient for bringing the fluid's temperature to the second temperature.    
   
   
       17 . The method of  claim 15 , further comprising: 
 adjusting the heating unit's heating power in dependence on at least one of: a type of separation system, a type of solvent, a slope of a solvent gradient, a flow rate of the fluid.