Valves
Our offer includes manual valves, nano-micro and analytical injection and switching valves. We also supply accessories as well as spare parts for these injection valves / switching valves.
>> PDF Injection & Switching Valves
Under the link you will find the product PDF. You can download the PDF and save it with a "right-click".
>> PDF Injection & Switching Valves
Under the link you will find the product PDF. You can download the PDF and save it with a "right-click".
Sample injection valves
Types and Performance RHEODYNE models ending in -25 are dual mode injectors. Dual mode injectors can be filled by two different methods: partial loop filling and full loop filling. They are injectors for variable volumes, as they allow the filling of the sample loop with different sample volumes. These Dual Mode Injectors, also called Frontloading Injectors, have a built-in grip needle port for sample loading. The unique RHEODYNE injection port design allows direct connection between the needle tip and sample loop without sample loss during sample loading. RHEODYNE models ending in -10 are single mode injectors. Here the sample loop is completely filled. These injection valves are referred to as fixed loop injectors because the sample loop determines the sample volume. These injectors require a loop filler port because they do not have a built-in needle port. There is thus no direct connection between the syringe and the sample loop. Therefore, a significant excess of sample must be used to completely fill the loop filler port and sample loop. RHEODYNE models with the suffix "i" are identical to the models with the same model number, but additionally have a built-in position switch. This switch provides the chromatograph with a reproducible start signal for marking the injection time in the data system. The reproducibility of manual sample dispensing valves depends on the skill of the operator, the accuracy of the syringe and the method of filling. The partial blending method has a typical reproducibility of 1.0% relative standard deviation (RSD). The complete blending method yields a reproducibility of 0.1% RSD for sample loops ≥ 5μl.
"MX" automation modules
The handy size and easy installation make "MX" modules the preferred solution for all high pressure liquid circuit and sample injection applications. Many micro-applications can use nano-modules. Nano Modules With a 10 nl sample loop and, more importantly, excellent dispersion characteristics, the Rheodyne "MX" Nano-Injector is the perfect solution for nanoproduction or micro-applications. All three Nano "MX" modules take advantage of Rheodyne's proprietary biocompatible DuraLife ™ III technology for significantly extended switching cycles. "MX" Nano-dispersion 6- and 10-port switching modules are ideal for on-line sample preparation and LC / MS column switching with minimal band broadening. Analytical Modules The "MX" Semiautomatic Injector combines the ease of use of the Rheodyne 7725i with the precision circuitry of an electrically operated valve. A specially developed needle channel is used to enter the sample directly into the valve. At the touch of a button, the sample is injected. By connecting the injector to a make contact, a sample can be dispensed during system equilibration and injected as soon as the system is ready. Outstanding Performance "MX" modules are also available in analytical 6-port and 10-port low dispersion valves. All Rheodyne "MX" modules include the miniature "Mighty Valve", which has been tested for continuous operation and is used by many instrument manufacturers worldwide. Versatile "MX" modules are designed to increase productivity, increase lab productivity and make work easier.
The handy size and easy installation make "MX" modules the preferred solution for all high pressure liquid circuit and sample injection applications. Many micro-applications can use nano-modules. Nano Modules With a 10 nl sample loop and, more importantly, excellent dispersion characteristics, the Rheodyne "MX" Nano-Injector is the perfect solution for nanoproduction or micro-applications. All three Nano "MX" modules take advantage of Rheodyne's proprietary biocompatible DuraLife ™ III technology for significantly extended switching cycles. "MX" Nano-dispersion 6- and 10-port switching modules are ideal for on-line sample preparation and LC / MS column switching with minimal band broadening. Analytical Modules The "MX" Semiautomatic Injector combines the ease of use of the Rheodyne 7725i with the precision circuitry of an electrically operated valve. A specially developed needle channel is used to enter the sample directly into the valve. At the touch of a button, the sample is injected. By connecting the injector to a make contact, a sample can be dispensed during system equilibration and injected as soon as the system is ready. Outstanding Performance "MX" modules are also available in analytical 6-port and 10-port low dispersion valves. All Rheodyne "MX" modules include the miniature "Mighty Valve", which has been tested for continuous operation and is used by many instrument manufacturers worldwide. Versatile "MX" modules are designed to increase productivity, increase lab productivity and make work easier.
Tips for using injectors
On models 7125, 7725 and other front-loading models, the sample loops can be partially or completely filled. Below is a summary of the possibilities. 1) Steps to inject a sample a) In the LOAD position, insert the syringe into the needle port as far as it will go. b) Push the sample into the injector, quickly turn the handle to the INJECT position. c) Remove the syringe. d) Wait until you want to analyze the next sample and then turn the handle back to the LOAD position. 2) Rinse in the INJECT position, not in LOAD After turning the handle to the INJECT position, you can remove the syringe. Stay in the INJECT position to allow the sample loop to flow continuously through the mobile phase. Manual flushing of the needle port is rarely necessary to prevent cross-contamination. A patented direct connection port connects the tip of the syringe needle directly to the end of the sample loop. There is no connection channel that holds sample back into the sample loop when the next sample is to be loaded. It is advisable to rinse the needle port after 10 or 20 injections. This keeps it filled with liquid and wets the syringe needle or dilutes any sample that contaminates this area during insertion or removal of the syringe. It also keeps the needle port and the drain capillary filled with liquid or prevents inadvertent gas bubbles in the sample loop. For rinsing use 0.1 to 1 ml of mobile phase. Rinse at the INJECT position to allow the fluid to exit directly from the outlet capillary and bypass the loop that is simultaneously flushed by the pump.
On models 7125, 7725 and other front-loading models, the sample loops can be partially or completely filled. Below is a summary of the possibilities. 1) Steps to inject a sample a) In the LOAD position, insert the syringe into the needle port as far as it will go. b) Push the sample into the injector, quickly turn the handle to the INJECT position. c) Remove the syringe. d) Wait until you want to analyze the next sample and then turn the handle back to the LOAD position. 2) Rinse in the INJECT position, not in LOAD After turning the handle to the INJECT position, you can remove the syringe. Stay in the INJECT position to allow the sample loop to flow continuously through the mobile phase. Manual flushing of the needle port is rarely necessary to prevent cross-contamination. A patented direct connection port connects the tip of the syringe needle directly to the end of the sample loop. There is no connection channel that holds sample back into the sample loop when the next sample is to be loaded. It is advisable to rinse the needle port after 10 or 20 injections. This keeps it filled with liquid and wets the syringe needle or dilutes any sample that contaminates this area during insertion or removal of the syringe. It also keeps the needle port and the drain capillary filled with liquid or prevents inadvertent gas bubbles in the sample loop. For rinsing use 0.1 to 1 ml of mobile phase. Rinse at the INJECT position to allow the fluid to exit directly from the outlet capillary and bypass the loop that is simultaneously flushed by the pump.
Tips for using injectors
a) Partial Filling Range If the volume of the injected sample is less than half the loop volume, the curve is linear. The sample does not reach the end of the loop. Within this range, the performance depends on the syringe and the operator.
b) Nonlinear area If the volume of the injected sample is between half and double loop volume, the curve is non-linear. Sample from the loop is lost, so the reproducibility is poor. If the volume of the injected sample is equal to the loop volume, you are in this range of poor performance.
c) Complete-Filling area If the volume of the injected sample is a multiple of the loop volume, the loop contains only pure sample that is not diluted by mobile phase residues. Within this range, the reproducibility is highest. In single-mode injectors, the sample must pass through a connection channel before it reaches the loop. Because some of the sample injected with the syringe remains in the connecting channel, only an unknown amount reaches the sample loop. High reproducibility is therefore achieved with single mode injectors only with the "complete-filling method".
a) Partial Filling Range If the volume of the injected sample is less than half the loop volume, the curve is linear. The sample does not reach the end of the loop. Within this range, the performance depends on the syringe and the operator.
b) Nonlinear area If the volume of the injected sample is between half and double loop volume, the curve is non-linear. Sample from the loop is lost, so the reproducibility is poor. If the volume of the injected sample is equal to the loop volume, you are in this range of poor performance.
c) Complete-Filling area If the volume of the injected sample is a multiple of the loop volume, the loop contains only pure sample that is not diluted by mobile phase residues. Within this range, the reproducibility is highest. In single-mode injectors, the sample must pass through a connection channel before it reaches the loop. Because some of the sample injected with the syringe remains in the connecting channel, only an unknown amount reaches the sample loop. High reproducibility is therefore achieved with single mode injectors only with the "complete-filling method".
Tips for using injection valves
Q: "Which method should I use and which Rheodyne sample injectors are used for this method?" A: There are 2 types of injectors: Dual Mode Injectors and Single Mode Injectors. Dual mode injectors allow both partial and complete filling of the sample loop, while single mode injectors allow only complete filling. See Sample Injection Valves. If you create test series, sample material is scarce or you want to use different sample volumes, then a dual-mode injector with a large-volume sample loop is suitable. Only Dual Mode Injectors allow for the "Partial Filling Method", where you can easily change your sample volumes by setting the syringe volume (up to half of your loop volume). Once you start routine analysis or have plenty of sample available, both are dual Mode as well as a single mode injector suitable. Both types of injectors allow the "complete-filling" method, in which the sample loop is filled with an excess of sample. Complete filling of the sample loop maximizes the reproducibility of your results.
Q: "Which method should I use and which Rheodyne sample injectors are used for this method?" A: There are 2 types of injectors: Dual Mode Injectors and Single Mode Injectors. Dual mode injectors allow both partial and complete filling of the sample loop, while single mode injectors allow only complete filling. See Sample Injection Valves. If you create test series, sample material is scarce or you want to use different sample volumes, then a dual-mode injector with a large-volume sample loop is suitable. Only Dual Mode Injectors allow for the "Partial Filling Method", where you can easily change your sample volumes by setting the syringe volume (up to half of your loop volume). Once you start routine analysis or have plenty of sample available, both are dual Mode as well as a single mode injector suitable. Both types of injectors allow the "complete-filling" method, in which the sample loop is filled with an excess of sample. Complete filling of the sample loop maximizes the reproducibility of your results.
• Bursting pressure of PEEK capillaries For most applications, PEEK capillaries can be used instead of stainless steel capillaries. PEEK is inert to almost all organic solvents and is biocompatible. Unlike metal, plastic is viscoelastic and therefore its yield strength is not well defined. The bursting pressure of PEEK capillaries is influenced by many factors. PEEK capillaries burst at lower pressures when: • Increasing the inside diameter
• increase the temperature
• increase the cycle time
• increase the concentration of organic solvents
• expose the capillaries to certain solvents. DMSO, THF and methylene chloride cause swelling of the PEEK capillaries. Concentrated nitric acid and sulfuric acid soften the PEEK capillaries.
• increase the temperature
• increase the cycle time
• increase the concentration of organic solvents
• expose the capillaries to certain solvents. DMSO, THF and methylene chloride cause swelling of the PEEK capillaries. Concentrated nitric acid and sulfuric acid soften the PEEK capillaries.
High pressure switching valves
Rheodyne offers manual high-pressure switching valves to simplify process operations and improve the speed, resolution and sensitivity of HPLC analysis. The switching valves are available in 316 stainless steel and PEEK, with either 1.6 mm (1/16 ") or 3.2 mm (1/8") ports. Column Selection The six-position valves are used for column selection. With these valves, you can switch from one column to the other without having to manually disconnect the connections. In this way, it is easy for each analytical method to define a separate column. Such fixed columns eliminate delays in equilibration, reduce noise and extend the life of the column. Turn the valve handle to select the column for the previously defined method. The off-line switched columns are automatically closed at both ends. Column Switching Two-position valves are used to divert the mobile phase during analysis without changing the separation method, or to perform sequential separations with different columns or mobile phases. Although Model 7000 is the most widely used and versatile switching valve, other models have specific uses, such as: for the three-or four-way circuit. Many models have both standard and large holes. They carry the suffix "L". L models use 1/16 "fittings and capillaries, but have larger diameter holes than non-L models, L models can handle higher flow rates, and large holes can be used when pressure drops need to be limited Large bore valves have lower pressure drops than standard bore valves.
Rheodyne offers manual high-pressure switching valves to simplify process operations and improve the speed, resolution and sensitivity of HPLC analysis. The switching valves are available in 316 stainless steel and PEEK, with either 1.6 mm (1/16 ") or 3.2 mm (1/8") ports. Column Selection The six-position valves are used for column selection. With these valves, you can switch from one column to the other without having to manually disconnect the connections. In this way, it is easy for each analytical method to define a separate column. Such fixed columns eliminate delays in equilibration, reduce noise and extend the life of the column. Turn the valve handle to select the column for the previously defined method. The off-line switched columns are automatically closed at both ends. Column Switching Two-position valves are used to divert the mobile phase during analysis without changing the separation method, or to perform sequential separations with different columns or mobile phases. Although Model 7000 is the most widely used and versatile switching valve, other models have specific uses, such as: for the three-or four-way circuit. Many models have both standard and large holes. They carry the suffix "L". L models use 1/16 "fittings and capillaries, but have larger diameter holes than non-L models, L models can handle higher flow rates, and large holes can be used when pressure drops need to be limited Large bore valves have lower pressure drops than standard bore valves.
