OW Series, Rev. 04.01.27 OW Series Objective Warmers 1125 Dixwell Avenue, Hamden, CT 06514 (800) 599-4203 / (203) 776-0664 (203) 776-1278 - fax
OW Series, Rev. 04.01.27 Table of Contents DESCRIPTION...3 INTRODUCTION...4 Heating approaches...4 Specimen heating...4 Environment heating... 4 Objective heating...4 SETUP...5 General Comments...5 Assembly...5 OPERATION...6 APPENDIX...7 Specifications...7 Cleaning/Maintenance...7 Warranty and Service...7 Warranty...7 Service...7
OW Series, Rev. 04.01.27 3 The OW-37 Objective Warmer from Warner Instruments provides a simple and effective method for maintaining a stable temperature within a microscope objective. This, in turn, permits the reduction of the thermal gradient between the lens and specimen experienced with immersion optic microscopy. A thermally controlled heated collar attaches to the microscope nosepiece below the objective. The collar incorporates a resistor block and thermistor which allows the included electronic controls to maintain the OW-37at a well maintained and constant temperature. Heat generated by the collar is not directly communicated to the microscope objective, but is instead distributed around the objective body by a conducting sleeve. The conducting sleeve warms the surrounding air which then gently warms the objective. This approach allows the apparatus to take full advantage of the thermal heat characteristics of the surrounding air. Collars and sleeves are available to fit microscope objectives from most manufacturers and custom designs are available from Warner Instruments. THIS EQUIPMENT IS NOT DESIGNED NOR INTENDED FOR USE ON HUMAN SUBJECTS
OW Series, Rev. 04.01.27 4 INTRODUCTION A common problem experienced by researchers using immersion optics is the loss of thermal control of the bathing solution directly above the microscope objective. The need to keep a specimen at a temperature different from ambient during observation is directly compromised by the heat-sink character of the objective/microscope. While this can be a difficult problem in general, it is particularly nasty when using an inverted microscope with very short working distance objectives. Clearly, the change in temperature at the objective is highly dependent on several factors, including the temperature of the perfusing solution, the temperature of the objective, the conductance of the objective and the solution flow rate. However, it has been observed that the solution temperature directly above an immersion objective can change as much as 10 C for a 37 C solution perfusing at 5 ml/min in an apparatus maintained at ambient temperature. Heating approaches Several approaches have been taken to address the issue outlined above. These include directly heating the specimen, heating the environment, and heating the microscope objective. Specimen heating Specimen heating is the most direct way to manipulate the temperature of a sample. Examples of this approach are heated cover slides and platforms, in-line solution heaters, and various Peltier driven devices. However, specimen heating is also the least effective method when used with immersion objectives and is usually used in conjunction with of one of the other strategies described below Environment heating Another approach is to place the entire microscope (or at least the stage, lens and sample chamber) within a specially designed thermal enclosure. An advantage to this strategy is that the microscope and its components are brought to a uniform temperature. Disadvantages are that the system changes state very slowly and users must access the stage area through possibly restrictive doors and openings. Objective heating The most common microscope objective heaters, called objective-lens heaters, use a heated collar or resistive wire placed in direct contact with the body of the objective, often near the lens. Objective-lens heaters can be combined with specimen heaters to control the thermal gradient between the specimen and the objective. This allows a specimen heating system, such as an in-line solution warmer, to become more effective and efficient. One drawback to objective heating is that heat energy is applied directly to the objective which can result in an observable thermal cycling of the objective. The direct application of heat energy can alter the focus of the lens (when in use), and can also shorten the working life of the objective. While the OW-37 is also designed as an objective-lens warmer, it achieves its task without exposing the microscope objective to significant stresses.
OW Series, Rev. 04.01.27 5 SETUP General Comments The parts described are shown in the figure to the right and are numbered according to the image. The OW-37 Objective Warmer is comprised of a heated collar (1) which is mounted underneath your microscope objective, an aluminum conducting sleeve (2) inserts within the collar and a plastic thermal shield (3) surrounds the collar-sleeve assembly. A power distribution module (4) routes power to the temperature controller (6), and a wall mounted adapter (5) provides overall power. The heated collar (1) has a short cable with the temperature controller (6) attached to its end. The power distribution module (4) connects to the temperature controller (6) via a supplied connecting cable (7). Assembly 1. Remove the cover of your microscope stage to reveal the objective-nosepiece assembly. 2. Unscrew the objective to be warmed from the nosepiece. 3. Position the collar (1) under the objective and reattach the objective to the microscope nosepiece. Note: Before tightening the objective into place, position the collar so that the power cable routes smoothly away from the nosepiece. (See figure to the right.) 4. Place the conducting sleeve (2) within the collar by aligning the pin within the slot. 5. Place the plastic thermal shield (3) over the completed assembly. Note: Make sure that the plastic shield does not extend above the top of the objective. (See figure to the right.) 6. Connect the temperature controller (6) to the power distribution module (4) using the connecting cable (7). 7. Connect the power supply (5) to the power distribution module (4) and plug it in.
OW Series, Rev. 04.01.27 6 8. Optionally, a battery or similar device can be used to power the OW-37. Connect the positive lead from the battery to the to the red banana connector on the power distribution module. Likewise, connect the negative lead from the battery to the black banana connector. The external source (battery, etc.) must be between 9-16 VDC and capable of delivering currents up to 1 A. OPERATION 1. Make all connections as described. Powering the distribution module (4) energizes the apparatus. 2. The temperature controller (6) has a small trim screw used to adjust the temperature of the heated collar (1). The controller is factory set to 37 C. Note: Since the microscope objective is warmed through the buffering heat capacity of the surrounding air, allow sufficient time for the system to stabilizes before changing the setting on the temperature controller. 3. Turning the trim screw clockwise raises the temperature setting of the heated collar, which in turn warms the microscope objective. Maximum temperature is 60 C. The temperature of the objective should be monitored near the lens with a separate measuring device to determine the proper setting of the heated collar. Ideally, the temperature of the microscope objective should be set within 5 C of, but lower than, the temperature of the specimen. In practice, this temperature may be difficult to achieve or unadvisable for the objective. In this case, the system should be adjusted to the highest temperature permitted that will minimize the temperature gradient between the lens and the specimen. Once a proper trim setting is found, subsequent adjustments are usually unnecessary. Note: Lens manufacturers recommend keeping microscope objective temperatures below a specific limit. Adjust the temperature controller to account for the objective manufacturers specifications.
OW Series, Rev. 04.01.27 7 APPENDIX Specifications Temperature Range: 37-60 C AC Power (supplied adapter): 12 VDC; 1.2A Battery (optional): 9-16 VDC; 1A Materials: Anodized aluminum Cleaning/Maintenance The OW-37 is constructed of anodized aluminum. It can be easily cleaned with common laboratory detergents or ethyl alcohol (EtOH). Do not autoclave. NOTE: Remove from microscope before cleaning. Warranty and Service Warranty The OW-37 is covered by our Warranty to be free from defects in materials and workmanship for a period of one year from the date of shipment. If a failure occurs within this period, we will either repair or replace the faulty component(s). This warranty does not cover failure or damage caused by physical abuse. In the event that repairs are necessary, shipping charges to the factory are the customer's responsibility. Return charges will be paid by Warner Instruments. Service We recommend that all questions regarding service be referred to our Technical Support Department. Normal business hours are 8:30 AM to 5:00 PM (EST), Monday through Friday. We are located at 1125 Dixwell Avenue, Hamden, CT 06514. We can be reached by phone at (800) 599-4203 or (203) 776-0664. Our fax number is (203) 776-1278. E-mail us at support@warneronline.com or through the contact section of our website at http://www.warneronline.com.